SYNTHESIS, CHARACTERIZATION AND PROPERTIES OF COORDINATION-
AND LOW BAND GAP POLYMERS FOR POTENTIAL CATALYTIC AND
PHOTOVOLTAIC APPLICATIONS
BY
CHRISTOPHER M. MACNEILL
A Dissertation Submitted to the Graduate Faculty of
WAKE FOREST UNIVERSITY GRADUATE SCHOOL OF ARTS AND SCIENCES
in Partial Fulfillment of the Requirements
for the Degree of
DOCTOR OF PHILOSOPHY
Chemistry
May 2011
Winston-Salem, North Carolina
Approved by:
Ronald E. Noftle, Ph. D., Advisor
David L. Carroll, Ph. D., Chair
Christa L. Colyer, Ph.D.
Stephen B. King, Ph. D.
Abdessadek Lachgar, Ph. D.
ACKNOWLEDGEMENTS
I would first like to acknowledge and extend my warmest regards and thanks to my advisor, Dr. Ronald E. Noftle, who has supported and guided me through my research over the past five years.
I would like to give a special thanks to Dr. Cynthia S. Day for her patience and kindness while collecting my crystal structure data for the coordination polymers project.
I was not the best crystal grower, but with her skills and help, I didn’t have to be.
I also want to thank my committee members Dr. David L. Carroll, Dr.
Abdessadek Lachgar and Dr. S. Bruce King for excellent discussions in all phases of my research, especially Dr. David L. Carroll and Dr. Robert C. Coffin for their mentoring with the organic solar cell project. I’d like to thank my fellow group members at the
Wake Forest Center for Nanotechnology and Molecular Materials, especially Eric
Peterson, Wanyi Nie, Gregory Smith and Chanitpa Khantha.
I would like to acknowledge my current and former group members, Melissa
Donaldson, Amy Marts, Alex MacIntosh, Eric Tainsh and Kasha Patel. Dr. Jianjun Zhang, and Sergio A. Gamboa for help with the coordination polymers project. I would also like to thank my fellow graduate students in the department of chemistry for making the past five years fun and enjoyable.
For my parents, Michael and Karen MacNeill, and my sisters, Kerri and Molly, for supporting me always in whatever I endeavor. Without them, I wouldn’t be the person
I am today. The utmost thanks to my beautiful fiancée, Samantha Miller, who has stuck with me through thick and thin. She is the most generous and kind-hearted person I’ve had the chance to know and I love her with all my heart.
ii TABLE OF CONTENTS
Page
Acknowledgements ii
Table of Contents iii
List of Figures ix
List of Schemes xiii
List of Equations xiii
List of Tables xiv
Abbreviations xv
Abstract xvii
Chapter
1. Introduction to 1
1.1. Coordination Polymers 1
1.1.1. Coordination Chemistry 1
1.1.2. Coordination Polymers 2
1.2. Tuning Pore Size and Functionality 3
1.3. Gas Adsorption Properties of Coordination Polymers 6
1.3.1. Carbon Dioxide Gas 6
1.3.2. Hydrogen Gas 7
1.4. Luminescent Properties of Coordination Polymers 8
1.4.1. Luminescence 8
1.4.2. Luminescence of Coordination Polymers 9
1.4.3. Luminescence of Lanthanide-based Coordination Polymers 9
iii
1.5. Catalytic Properties of Coordination Polymers 10
1.5.1. Zeolites vs. Coordination Polymers 10
1.5.2. Catalytic Sites in Coordination Polymers 11
1.5.3. Catalytic Reactions using Coordination Polymers 12
1.5.3.1. Cyanosilylation of Aldehydes 12
1.5.3.2. The Biginelli Reaction 14
1.5.3.3. Knoevenagel Condensation 15
1.6. Research Goal 17
2. Experimental 18
2.1. Materials 18
2.2. Methods 19
2.2.1. Analytical Methods 19
2.2.2. X-ray Diffraction Methods 19
2.3. Synthesis 20
2.3.1. Solvothermal Method 20
2.3.2. Reflux Method 22
2.3.3. Vapor Diffusion Method 23
2.3.4. Catalytic Experiments 25
2.3.4.1. Heterogeneous Catalysts 25
2.3.4.2. Homogeneous Catalysts 27
3. Synthesis, Crystal Structure and Properties of Coordination Polymers 1-4 28
3.1. Synthesis of Coordination Polymers 1-4 29
iv 3.2. Single Crystal X-ray Diffraction 29
3.2.1. Crystal structure of La2(2,5-TDC)3(DMF)2H2O . DMF (1) 29
3.2.2. Crystal structure of Gd2(2,5-TDC)3(DMF)2H2O (2) 32
3.2.3. Crystal structure of Eu4(C6H2O4S)6(H2O)2(DMF)3 (H2O/n-prOH) (3) 35
3.2.4. Crystal structure of Y(2,5-TDC)(DMF)2(NO3) (4) 37
3.3. Thermogravimetric Analysis 38
3.4. Infrared Spectroscopy 39
3.5. Solid State Photoluminescence 42
3.6. Catalytic Properties 43
3.7. Conclusion 46
4. Synthesis, Crystal Structure and Properties of Coordination Polymers 5-9 48
4.1. Synthesis of Coordination Polymers 5-9 49
4.2. Single Crystal X-ray Diffraction 50
4.2.1. Crystal Structure of Tb2(F4BDC)3(DEF)2EtOH2 . 2(DEF) (5) 50
4.2.2. Crystal Structure of Gd2(F4BDC)3(DEF)2EtOH2
. 2(DEF) (6), Eu2(F4BDC)3-(DEF)2EtOH2
. 2(DEF) (7), La2(F4BDC)3-(DEF)2EtOH2
. 2(DEF) (8) and Nd2(F4BDC)3-(DEF)2EtOH2
. 2(DEF) (9) 53
4.3. Thermogravimetric Analysis 53
4.4. Infrared Spectroscopy 54
v 4.5. Solid State Photoluminescence 55
4.6. Catalytic Properties 57
4.7. Conclusion 59
5. Introduction to 61
5.1. The Environment 61
5.2. History of Photovoltaics 62
5.2.1. The Photoelectric Effect 62
5.2.2. Inorganic Photovoltaics 62
5.2.3. Organic Photovoltaics 64
5.3. Theory and Device Physics of Organic Solar Cells 65
5.3.1. Open Circuit Voltage 66
5.3.2. Short Circuit Current 67
5.3.3. Fill Factor 67
5.4. Device Architectures of Organic Solar Cells 69
5.5. Critical Parameters of Organic Solar Cells 70
5.6. Research Goal 73
6. Experimental 75
6.1 Materials 75
6.2. Methods 75
6.2.1. Analytical Methods 75
6.2.2. Electrochemical Methods 76
6.2.3. X-ray Diffraction Methods 76
6.2.4. Photovoltaic Methods 77
vi 6.3. Synthesis 78
7. Synthesis, Characterization and Photovoltaic Properties of P1-P3 87
7.1. Synthesis of Polymers P1-P3 88
7.2. Thermogravimetric Analysis of P1-P3 91
7.3. UV-Visible Spectroscopy of P1-P3 92
7.4. Electrochemistry of P1-P3 92
7.5. X-ray Powder Diffraction of P1-P3 94
7.6. Photovoltaic Properties of P1-P3 95
7.7. Conclusion 97
8. Synthesis, Characterization and Photovoltaic Properties of P4-P11 99
8.1. Synthesis of Polymers P4-P11 100
8.2. Thermogravimetric Analysis of P7-P11 103
8.3. UV-Visible Spectroscopy of P7-P11 104
8.4. Electrochemistry of P7-P11 105
8.5. X-ray Powder Diffraction of P7-P11 106
8.6. Photovoltaic Properties of P7-P11 108
8.7. Solvent Additive Processing of Polymer P11 110
8.8. Conclusion 113
9. Synthesis, Characterization and Photovoltaic Properties of P12-P14 115
9.1. Synthesis of Polymers P12-P14 116
9.2. Thermogravimetric Analysis of P12-P14 117
9.3. UV-Visible Spectroscopy of P12-P14 118
vii
9.4. Electrochemistry of P12-P14 119
9.5. X-ray Powder Diffraction of P12-P14 120
9.6. Photovoltaic Properties of P12-P13 122
9.7. Conclusion 124
Conclusions 126
Future Work 129
References 131
Appendix A 154
Appendix B 221
Publishing Permission and License 231
Scholastic Vitae 256
viii
List of Figures Page
Figure 1: Examples of coordination polymers with different dimensionalities. 2
Figure 2: The molecular building block (MBB) approach to coordination polymers. Adapted from James.51 4
Figure 3: Organic linkers based on geometry for use in the synthesis of coordination polymers. 5
Figure 4: Coordination environment around (a) La3+(1) and (b) La3+(2) ion. 30
Figure 5: (a) The La(1)-La(2) dimer formed by four bridging TDC2- linkages. (b) A chain formed through linking of dimers from coordination polymer 1 shown down the a-axis. The La environment is shown as teal polyhedra, O (red), C (grey), S (yellow). 31
Figure 6: A perspective view of coordination polymer 1 along the a-axis with solvent molecules omitted for clarity. 32
Figure 7: The coordination environments around (a) Gd3+(1) and (b) Gd3+(2) ion. 33
Figure 8: (a) The Gd(1)-Gd(1) dimer formed by four bridging TDC2- linkages. b) The Gd(2)-Gd(2) dimer formed by four bridging TDC2- linkages. c) A chain formed through the linking of dimers 1 and 2 down the a-axis for coordination polymer 2. The Gd environment is shown as blue polyhedra. 34
Figure 9: The coordination environments around the (a) Eu3+(1) ion and (b) Eu3+(2) ion. 35
Figure 10: (a) The asymmetric unit of Eu(1) and Eu(2) (pink) linked by two TDC2- (bridging) linkages along with eight TDC2- linkages (all monodentate), two DMF molecules and one H2O molecule (bridging) forming Eu4(2,5-TDC)6(DMF)3(H2O)2(H2O/n-prOH) (3). (b) A chain formed through the linking of dimers in (a) of coordination polymer 3 down the a-axis. Carboxylates are shown in red. 36
ix
Figure 11: (a) A representation of the environment around the yttrium ion in coordination polymer 4 along the crystallographic ab-plane. b) A view of coordination polymer 4 along the crystallographic a-axis. 37
Figure 12: The TGA curves of coordination polymers 1-4. 38
Figure 13: The infrared spectra of coordination polymer 1 at room temperature (RT) and after heating to 380oC (compound 1a). 40
Figure 14: X-ray powder diffraction spectra comparing the room temperature pattern to the patterns at 380oC and 900oC of coordination polymer 1. 41
Figure 15: (a) Excitation (inset) and emission spectra of coordination polymer 3 excited at 390 nm. (b) Coordination polymer 3 under visible light (c) Coordination polymer 3 under UV light (long wavelength). 43
Figure 16: (a) A view of the contents of the asymmetric unit for Tb2(F4BDC)3(DEF)2(EtOH)2 · 2(DEF) (5). Hydrogen atoms have been omitted for clarity. (b) A view of the formula unit of 5 with two identical terbium atoms. (c) A view of the formula unit of 5, where the contents of the polyhedra represent the terbium atoms. 51
Figure 17: (a) A view of the dimer of 5 connected to other dimers through 2- six F4BDC linkages. (b) A view of (a) forming an overall 2D sheet with solvent molecules and hydrogen atoms omitted for clarity. 52
Figure 18: (a) A view of the 2D sheet of coordination polymer 5 along the b-axis. (b) The formation of a 3D layered topology from stacking of the infinite 2D sheets from (a). Lattice DEFs were omitted for clarity. 52
Figure 19: The TGA curves of coordination polymers 5-9. 54
Figure 20: The infrared spectra of coordination polymer 7 (as synthesized) and coordination polymer 7a (after evacuation to remove solvent from the lattice.) 55
Figure 21: (a) A picture of Tb 5, Eu 7 and La 8 coordination polymers under visible light. (b) A picture of Tb 5, Eu 7 and La 8 coordination polymers under UV light. (c) The solid state photoluminescence
x spectrum of Eu 7 excited at 392 nm. (d) The solid state photoluminescence spectrum of Tb 5 excited at 300 nm. 56
Figure 22: A schematic representation of the steps involved in generating photocurrent in a donor-acceptor polymer solar cell device. 66
Figure 23: The J-V curve (black) of a BHJ solar cell device under illumination. Characteristic open circuit voltage (Voc), short circuit current (Jsc) and FF (Area A/Area B), as well as the calculation of power conversion efficiency (PCE) are indicated on the figure. 68
Figure 24: A representation of (a) a bi-layer solar cell device, (b) a BHJ solar cell device and (c) a tandem solar cell device. 69
Figure 25: The TGA curve of P1 (black), P2 (blue) and P3 (red) under argon at 5oC/min. 91
Figure 26: The UV-vis absorption spectra of P1 (black), P2 (blue) and P3 (red) in DCB. 92
Figure 27: The cyclic voltammograms of P1 (black), P2 (blue) and P3 (red) films drop-cast from chloroform solution. 93
Figure 28: (a) The integrated powder diffraction patterns for P1 (black), P2 (blue) and P3 (red). Inset: 10 frames added together for P3. (b) A model of packing for P3. 95
Figure 29: Current-voltage characteristics of BHJ solar cells based on P1 (black), P2 (blue) and P3 (red) with PC61BM. 96
Figure 30: External quantum efficiency spectra of BHJ solar cells based on P1 (black), P2 (blue) and P3 (red) with PC61BM. 97
Figure 31: The UV-vis absorption spectra of P3 (red), P4 (black), P5 (green) and P6 (pink) in DCB. 102
Figure 32: The TGA curve of P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) under argon at 5oC/min. 103
Figure 33: The UV-vis absorption spectra of P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) in DCB. 104
Figure 34: The cyclic voltammograms of P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) films drop-cast from chloroform solution. 105
xi
Figure 35: The powder diffraction patterns for P7 (black), P8 (blue) and P9 (orange), P10 (green) and P11 (red). 107 Figure 36: Current-voltage characteristics of BHJ solar cells based on P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) with PC71BM. 109
Figure 37: External quantum efficiency spectra of BHJ solar cells based on P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) with PC71BM. 110
Figure 38: Summary of chlorobenzene ratio on device performance. (a) Summary of open circuit voltage and short circuit current density. (b) Summary of fill factor and power conversion efficiency. Points represent the average of at least eight devices with standard deviation. (c) The best current-voltage curves, and (d) the best external quantum efficiency curves for each condition. This figure is reproduced with permission from Wanyi Nie. 112
Figure 39: The TGA curve of P12 (blue), P13 (black) and P14 (red) under argon at 10oC/min. 118
Figure 40: The UV-vis absorption spectra of P12 (blue), P13 (black) and P14 (red) in chloroform solution. 119
Figure 41: The cyclic voltammograms of P12 (blue), P13 (black) and P14 (red) films drop-cast from chloroform solution. 120
Figure 42: The powder diffraction patterns for P12 (blue), P13 (black) and P14 (red) on loop. 121
Figure 43: Current-voltage characteristics of BHJ solar cells based on 1:1.5 (w:w) P12:PC61BM (blue) and 1:2.5 (w:w) P13:PC61BM (black) with 2 % DIO additive. 122
Figure 44: External quantum efficiency spectra of BHJ solar cells based on 1:1.5 (w:w) P12:PC61BM (blue) and 1:2.5 (w:w) P13:PC61BM with 2 % DIO additive (black). 123
xii List of Schemes Page
Scheme 1: The cyanosilylation of aldehydes using a coordination polymer (CP) as a heterogeneous catalyst. 12
Scheme 2: The Biginelli reaction using a CP as a heterogeneous catalyst. 14
Scheme 3: The Knoevenagel condensation reaction using a CP as a heterogeneous catalyst. 16
Scheme 4: The Biginelli reaction using CP 1a as a heterogeneous catalyst. 44
Scheme 5: The proposed mechanism for the Biginelli reaction using an activated coordination polymer as a heterogeneous catalyst. 46
Scheme 6: The synthesis of 4,8-dihydrobenzo[1,2-b;4,5-b’]dithiophene- 4,8-dione 28. 88
Scheme 7: The synthesis of the bis-stannylated monomers 34-37. 88
Scheme 8: The synthesis of polymers P1-P3. 89
Scheme 9: The synthesis of polymers P4-P6. 100
Scheme 10: The synthesis of polymers P7-P11. 101
Scheme 11: The synthesis of polymer P12. 116
Scheme 12. The synthesis of polymers P13-P14. 117
List of Equations
Equation 1. An equation relating the band gap (Eg) of a polymer to the 200 open circuit voltage (Voc) by Baruch and co-workers. 67
xiii List of Tables Page
Table 1: Catalytic syntheses of dihydropyrimidinones using CP 1a and 2a under different reaction conditions.a 45
Table 2: Catalytic syntheses of dihydropyrimidinones using CP 7, 7a, 8 and 9 under different reaction conditions.a 58
Table 3: Table of results from electrochemical and UV-visible spectroscopy measurements of polymers P1-P3. 93
Table 4: Photovoltaic characteristics of best devices prepared from P1-P3 and PC61BM. 96
Table 5: Table of results from electrochemical and UV-visible spectroscopy measurements of polymers P7-P11. 106
Table 6: Photovoltaic characteristics of best devices prepared from P7-P11 and PC71BM. 110
Table 7: Table of results from electrochemical and UV-visible spectroscopy measurements of polymers P12-P14. 120
Table 8: Photovoltaic characteristics of best devices prepared from P12-P13 and PC61BM. 124
Table 9: A comparison of the photovoltaic characteristics of P13 at different (w:w) ratios PC61BM and using additive processing. The highest PCE for the devices can be seen in parenthesis. 124
xiv ABBREVIATIONS
PSe 1,2,5-selenadiazolo[3,4-c]pyridine
PT 1,2,5-thiadiazolo[3,4-c]pyridine
BTC 1,3,5-benzenetricarboxylate
DIO 1,8-diiodooctane
BSe 2,1,3-benzoselenadiazole
BT 2,1,3-benzothiadiazole
F4BDC 2,3,5,6-tetrafluoro-1,4-terephthalic acid
2,5-TDC 2,5-thiophenedicarboxylate
BDT Benzodithiophene
CN Chloronapthalene
CP Coordination Polymer
CPDT Cylcopentadithiophene
DCB Dichlorobenzene
EQE External Quantum Efficiency
FF Fill Factor
HOMO Highest Occupied Molecular Orbital
HIOM Hybrid Inorganic-Organic Material
ITO Indium-Tin Oxide
LUMO Lowest Unoccupied Molecular Orbital
MOF Metal-Organic Framework
DMF N,N-dimethylformamide
Mn Number Average Molecular Weight
xv Voc Open Circuit Voltage
OPV Organic Photovoltaic
PCE Power Conversion Efficiency
Jsc Short Circuit Current
TGA Thermogravimetric Analysis
TPD Thienopyrroledione
Mw Weight Average Molecular Weight
xvi ABSTRACT
Organic/Inorganic Polymeric Materials:
Four three dimensional-coordination polymers built of lanthanide ions and 2,5-
TDC2- linkers along with five isostructural two-dimensional lanthanide-based
coordination polymers with F4BDC linkers have been synthesized. The coordination polymers were characterized by single-crystal and powder X-ray diffraction. For
Compounds 1-4, the Ln3+ metal ions are eight-coordinate, linked to other Ln3+ metal ions
by six 2,5-TDC2- units and varying amounts of coordinating solvent molecules. The metal ions form a distorted sinusoidal chain which is bridged to other chains through 2,5-TDC2- linkers to form a 3D framework. The solvent molecules occupy the rhombic channels of the frameworks. For compounds 5-9, the Ln3+ metal ions are linked to an adjacent Ln3+
2- metal ions through the oxygen atoms of two bridging μ2-F4BDC ligands and two μ3-
2- F4BDC bridging ligands to form a Ln2O18 dimer. The Ln2O18 dimers are linked to each-
2- other through four F4BDC ligands to form 2D sheets. Compounds 1-9 were further
characterized using thermogravimetric analysis and infrared spectroscopy. Studies of the
photoluminescence properties of compounds 3, 5 and 7 as well as the catalytic activity of
compounds 1, 7, 8 and 9 in the Biginelli reaction, are presented.
Organic Polymeric Materials:
Through subtle manipulation of a solubilizing side chains on the backbone of 4,8-
dialkoxybenzo[1,2-b:4,5-b’]dithiophene (BDT)/2,1,3-benzothiadiazole (BT) copolymers,
the molecular weight and the solution processability of the polymers can be dramatically
improved. When 2-ethylhexyl side chains are attached to the 4- and 8-positions of the
xvii BDT unit, a chloroform-soluble copolymer fraction with a weight-average molecular
weight (Mw) of 3.4 kg/mol is obtained (P2). By moving the ethyl branch from the 2- to
the 1- position on the hexyl chain, we obtain a chloroform soluble fraction with an Mw of
68.8 kg/mol (P3). As a result of this side chain alteration, the shape of the absorption profile is dramatically altered, λmax is shifted from 575 to 637 nm, the hole mobility as determined by thin film transistor (TFT) measurements is improved from 9 x 10-7 to 7 x
10-4 cm2/Vs, and the solar cell power conversion efficiency (PCE) of the bulk
heterojunction (BHJ) device is enhanced from 0.31 % to 2.91 %.
By further increasing the branch on the BDT backbone from a six carbon branched chain to an eleven carbon branched chain (P7-P11), soluble high molecular weight copolymers were achieved. Varying the co-monomer from 2,1,3-benzothiadiazole, to other electron withdrawing monomers (P8-P10), allowed us to lower the band gap and
achieve decent efficiencies. High efficiency organic photovoltaic (OPV) devices
comprised of P11 and phenyl-C71-butyric acid methyl ester (PC71BM) were fabricated by
additive processing with 1-chloronapthalene (CN). When the active layer is cast from
pristine chlorobenzene, the average PCE is 1.41 %. Our best condition, using 2 %
chloronapthalene as a solvent additive in chlorobenzene, results in an average PCE of
5.65 %, with a champion efficiency of 6.05 %.
The donor monomer was varied from BDT to another donor monomer with a
lower band gap (cyclopentadithophene, CPDT) and compared to a known BDT-based
copolymer (P12) using the same thienopyrroledione acceptor monomer (P13). The polymer showed excellent solubility at room temperature in chlorinated solvents. The absorption onset for P1 is close to 740 nm as compared with ~685 nm for PBDTTPD,
xviii corresponding to an optical band gap of 1.67 eV, which is 0.15 eV lower than PBDTTPD.
The photovoltaic characteristics of the polymer were determined under AM 1.5g illumination. The P13:PCBM BHJ device showed a high Voc (0.92 V) and Jsc (8.02 mA/cm2) as well as a good PCE (2.43 %), while the best device with 2% solvent additive
gave a PCE of 3.47 %.
xix CHAPTER 1: INTRODUCTION
1.1. Coordination Polymers
1.1.1. Coordination Chemistry
A coordination compound is a material that contains a central metal ion surrounded by ligands that are coordinated to the metal center through coordination bonds. Three features will determine how a coordination compound assembles: 1.) the structure of the binding site; 2.) the spacer separating the binding sites and 3.) the coordination environment around the metal center. 3 All three features have great bearing
on whether a certain ligand can coordinate to a metal ion. One can anticipate a certain
dimensionality to these motifs by understanding the properties of the metal and ligands.
These compounds are generally finite zero-dimensional (0D) materials. Many
coordination compounds can form other supramolecules such as cubes, cages,4-5 knots,6 catenanes,7 rotaxanes,8 clusters9 or helicates.10 They may have the ability to hydrogen
bond or π-π stack in three dimensions; however, coordination compounds usually contain
monodentate or bidentate ligands and these ligands form discrete 0D coordination
complexes. Coordination polymers, however, contain bi-, tri-, or tetradentate ligands,
which can coordinate to other metal centers and extend in all three dimensions to create
infinite extended structures (Figure 1). Many of the same rules outlined above for 0D
coordination compounds can be applied to multi-dimensional coordination polymers.
1 1.1.2. Coordination Polymers
The term “coordination polymer” dates back to the 1960s when Balair compared organic compounds to inorganic compounds that can be polymeric.11-12 Coordination
polymers are not polymeric in the sense that organic polymers are because they do not
have extended covalent bonds. Recently, the term “coordination polymers” (CP) has been
used interchangeably with the terms “metal-organic framework (MOF),” which was
coined by Yaghi in 1995,13 and hybrid inorganic-organic material (HIOM). A
coordination polymer is defined as “a metal coordination
N N Cl Cu H2O H2O Cl N Cl Cl N N N Cu N N Cu n Cl Cl H2O H2O
0D coordination compound 1D coordination polymer
Cu N NCu Cl Cl Cu N NCu N N N N Cl N Cl N
N N Cu N NNCu N
N N N N Cu N N Cu Cl Cl Cu N N Cu N N N N Cl Cl N N N N N N
Cu N N Cu N N
N N N Cu N NCu Cl Cl Cu N NCu N N Cl Cl N N N N 2D coordination polymer Cu N NCu
3D coordination polymer
Figure 1: Examples of coordination polymers with different dimensionalities.
2 compound in which a ligand bridges between metal centers, and in which each metal
center binds to more than one ligand to create an infinite array of metal centers.”14
Inorganic chemists tend to use the term “coordination polymer,” while solid state
chemists use “metal organic framework.”15 Metal-organic frameworks tend to exhibit a
three dimensional structure with permanent porosity, while coordination polymer is a
much broader term and encompasses all one-, two- and three-dimensional materials that are polymeric. The metal acts as the node while the ligand acts as the spacer between nodes to form infinite one-, two- or three-dimensional networks. 16 A significant amount
of research focuses on the crystal engineering aspect of coordination polymers in an
effort to form novel topologies. Coordination polymers have also become an increasingly
significant field of research due to their various applications in the areas of gas
adsorption,17-18 catalysis,19-21 magnetism,22 luminescence,23 and medicine.24-25
1.2 Tuning Pore Size and Functionality
The molecular building block approach26-29 (MBB) to functional materials is a
concept used to attempt to understand the dimensionality of the ensuing material before a
synthetic protocol is ever carried out. Knowing the coordination preferences of the metal,
along with the geometry of the spacer, one can predict the topology that will ensue from
the building blocks chosen (Figure 2). This ability to formulate novel topologies based on
coordination environment and ligand flexibility has been of interest to many research
groups. Use of a rigid linker as the backbone will allow for greater prediction of the
ensuing network geometry because of less orientational freedom of the ligand (Figure 3).
3
metal coordination geometry organic linker geometry
M M M M M
M M M M M M M M M M M M M M M M M M M M 1D chain M M M M M M 2D sheet 3D framework
2D sheet
Figure 2: The molecular building block (MBB) approach to coordination polymers.
Adapted from James.51
Guest solvent molecules will fill the voids left by the metal and ligands. These
frameworks should exhibit permanent porosity upon removal of guest solvent molecules
from the structure. The pore size of a CP is dictated by cautious choice of the organic
linker. The larger the organic spacer, the greater the potential pore size can be. If a linker
is large enough, and not rigid, the framework may interpenetrate, giving a smaller pore
sizes with potentially greater surface area. Transition metal-based CPs incorporating
Zn,30-31 Cd,32-33 Cu34-35 and Mn36-37 have been greatly explored; however, lanthanide- based CPs are still in their infancy, mainly because of the lack of predictable topologies
due to their flexible coordination environments. Lanthanide ions are hard acids, and, thus,
4 organic ligands, which are hard bases, are required. Organic ligands, such as
dicarboxylates, are used for this purpose. The versatility of their coordination modes
makes them attractive linkers for bridging lanthanide centers. Recently most of the work
with lanthanide metal ions and O-donor ligands has been with rigid linkers such as 1,4-
benzenedicarboxylate, 1,2,4,5-benzenetetracarboxylate, 1,3,5-benzenetricarboxylate, and
biphenyl-3,3’,5,5’-tetracarboxylate.38-41 Coordination polymers based on 2,5- thiophenedicarboxylic acid (2,5-TDC) are used in combination with another linker,
usually N-donor ligands such as pyridine, imidazole, bipyridine and 1,10-
phenanthroline.42-47 Only a few groups have engineered 2,5-TDC frameworks with
strictly 2,5-TDC as the O-donor48-50 Thiophene-based molecules have been known to
conduct charge extremely well. This is due to the lone pair of electrons on the sulfur atom,
which are easily delocalized around the ring.51
organic linker geometry
N CO2H
HO 2C CO2H CO2H
CO2H HO2C CO2H N HO2C CO2H
HO2C CO2H
CO2H CO H 2 HO2C CO 2H
CO2H HO2C CO2H HO C CO H HO2C 2 2 O CO2H O O O N CO2H CO2H HO2C CO2H S N N HO 2C S HO C CO H N 2 2 N N CO2H
Figure 3: Organic linkers based on geometry for use in the synthesis of coordination polymers
5 Other thiophene-based linkers such as 2,2’-bithiophene-5,5’-dicarboxylic acid52-53 and
thieno[3,2-b]thiophene-2,5-dicarboxylate,54-55 have been used as building blocks for the
synthesis of porous CPs.
1.3. Gas Adsorption Properties of Coordination Polymers
1.3.1. Carbon Dioxide Gas Adsorption
The increased amount of carbon dioxide (CO2) gas in the atmosphere, and its
impact on global warming has become a valid concern in our society. There are a few
ways to diminish the amount of CO2 entering the atmosphere, such as replacing fossil
fuels with nuclear power, using fuel cell technologies or trying to capture CO2 exhaust
from power plants before it is released into the atmosphere. Coordination polymers allow
us to address the latter. The ability to sequester and store CO2 will address the environmental concerns raised by the emission of too much carbon dioxide. Currently, fossil fuel plants are capturing CO2 by treating the gas with an amine solution. However,
this process is neither cost-, nor energy-efficient.56-57 Using these techniques, many
carbon-based materials58-60 and metal oxides61-62 have been tried, but these systems need
high reaction temperatures to adsorb CO2. Some coordination polymers offer a more efficient way to capture CO2 at lower reaction temperatures and lower enthalpies of
adsorption. They also show good selectivity towards CO2 in gas mixtures with CH4, CO
63-64 and N2.
Numerous frameworks such as Zeolitic Imidazolate Framework (ZIF-69), Hong
Kong University of Science and Technology (HKUST-1), Materials Institut Lavoisier
(MIL-101), Metal-Organic Framework (MOF-5) and MOF-177 have been studied for
6 65-70 their CO2 adsorption properties in the literature. ZIF-69, a framework built on zinc
3 metal ions and imidazolate ligands, showed uptakes of 69 cm /g CO2 at 270 K and 1 bar and has a BET surface area of 1070 cm2/g at 77 K.66 HKUST-1 is a framework made up
of Cu(II) ions with 1,3,5-benzenetricarboxylic acid as a linker to form a 3D framework.
2 3 BET calculations showed a surface area of 1570 cm /g and a CO2 uptake of 239 cm /g at
298 K and 50 bar.65-67 MIL-101 is a framework built on trimeric Cr (III) ions and 1,4-
65 benzenedicarboxylic acid. This framework has the largest CO2 uptake published to date
at 896 cm3/g at 298 K and 50 bar.
1.3.2. Hydrogen Gas Adsorption
Hydrogen storage through use of hydrogen-oxygen fuel cells, has become of
interest as a way of reducing our dependence on foreign oil and also for generation of
cleaner emissions. Materials such as hydrogen in its gas, liquid, or metal hydride form,
carbon-based materials, and zeolites have been investigated for their potential “on board”
hydrogen storage capabilities;71-76 however, use of these materials has encountered many
problems. Hydrogen gas and liquid hydrogen are not the safest choices and large amounts
of hydrogen would be lost during the filling and storage process. Metal hydrides have
slow uptake and release kinetics, which means high temperatures are needed to liberate
the hydrogen from the metal and a large amount of energy must be expended for uptake of hydrogen by the metal after it has been liberated.77 Investigations of the hydrogen
storage capabilities of materials with high surface areas such as zeolites and carbon based
materials have been reported; however, the heat of adsorption is small and uptake can be
achieved only at extremely low temperatures.
7 It wasn’t until 2003 that CPs received a lot of interest for their hydrogen
adsorption capabilities due to their tunable pore sizes and high porosity. Many zeolites
have surface areas around 900 m2/g, while some CPs have achieved surface areas of
10000 m2/g.78 MOF-5 was the first metal organic framework to be used for these
investigations because it was cheap and had a large surface area.79 Since then, hundreds
of reports on the hydrogen adsorption of CPs have been published. Many of these papers
show that, the greater the surface area of the framework, the greater the gravimetric
uptake of hydrogen by weight at 77K.80
1.4 Luminescent Properties of Coordination Polymers
1.4.1 Luminescence
There are two types of luminescence: fluorescence and phosphorescence.
Fluorescence is defined as the emission of light, after absorption of a photon of light at a
different wavelength. The emitted light is usually at a longer wavelength (lower energy) than the absorbed light. This phenomenon was observed by George Stokes in 1852.89 He
was working with a material, fluorite (CaF2), at the time, which was doped with
europium and emitted blue light. The term “Stokes shift” was coined later as the shift
between the absorption maximum and emission maximum for a given electronic
transition.90 A material that absorbs ultraviolet light emits it at a longer wavelength,
typically in the visible region. Phosphorescence involves the absorption of a photon, similar to fluorescence; however, there is a delay in the emission of the photon due to a
spin-forbidden transition. These phosphorescent lifetimes can last from several seconds
to hours.
8 1.4.2. Luminescence of Coordination Polymers
Coordination polymers, as possible luminescent materials, have only been considered since the early 2000s. Coordination polymers containing lanthanide ions are mainly used as electroluminescent devices or sensors because of their photophysical properties.81-86 Unlike most organic light-emitting devices, lanthanide coordination polymers have sharp emission bands that range over the entire visible spectrum (Eu, Tb and Tm)87 to the near IR region (Nd, Er, Yb).88 Coordination polymers are interesting luminescent materials because they exist in a crystalline form and have predictable topologies. Removal of solvent molecules from the framework allows for greater luminescence intensity because the solvent molecules can quench emission. Permanent porosity, combined with the rigidity of the framework, may also lead to increased luminescence lifetimes and other features not inherent in traditional inorganic complexes.
Permanent porosity allows the framework to adsorb certain molecules into the pores with close proximity to the metal centers, which may lead to a red shift in their spectra and/or help to increase the luminescence intensity of the material. The numerous coordination modes of the metal ions, along with a variety of organic linkers to choose from, make coordination polymers useful materials for future luminescent applications.
1.4.3 Luminescence of Lanthanide-based Coordination Polymers
The luminescence of pure lanthanide elements is typically weak, due to certain selection rules. In order to circumvent this, an organic molecule is used to act as an antenna. Typically, organic molecules that have π-bonds, which can absorb the incident light and transfer it to the lanthanide metal for re-emission, are used. There are a few
9 ways luminescence can be produced in a lanthanide CP, as outlined by Houk et al.91 1.)
Through the organic linker: as outlined above, organic molecules have π-bonds which
can absorb incident light. The luminescence can come from the linker and the energy can
be transferred to the metal ion and emitted as luminescence. 2.) Through the metal ion:
transition metals tend to quench luminescence, except for some d10 elements.92-94
Lanthanide ions have weak luminescence due to parity forbidden transitions; however, by using the antenna effect95 to absorb light and transfer it to the lanthanide metal, these
restrictions can be partially circumvented. 3.) Through adsorbed materials: certain
materials can be adsorbed into the pores of the framework which can help contribute to luminescence if in close proximity to the metal ion. 4.) Through π-π interactions: if the
organic linkers within the framework are close enough to have a π-π interaction, this can
contribute to luminescence because an excited complex is formed and ligand-to-ligand
charge transfer (LLCT) can occur.
Lanthanide frameworks, bound to carboxylate linkers such as 1,4-
benzenedicarboxylic acid and 2,2-bipyridine-4,4’-dicarboxylic acid, have been studied in
terms of their photophysical properties.96-98
1.5. Catalytic Properties of Coordination Polymers
1.5.1 Zeolites vs. Coordination Polymers
Coordination polymers have been studied for their heterogeneous catalytic
properties.99-102, 107-112 Coordination polymers have the ability to function as catalysts if
one can incorporate a functionalized ligand or an active metal site into the framework
structure. These catalytically active CPs are analogous to zeolites, which have been
10 studied and utilized extensively for their heterogeneous catalytic properties. Zeolites are
materials that incorporate SiO4 and AlO4 tetrahedral centers linked together through the
oxygen atoms to other Si or Al centers. These microporous materials have channel sizes
<10 Å. Their well defined pores have allowed zeolites to be utilized in the petroleum
industry for cracking of hydrocarbons. Their high thermal stability makes them useful catalysts under forcing conditions, where a thermally stable material is needed. Many different zeolites have been synthesized; however, due to the tetrahedral coordination environment and the bond length of the oxygen spacer, it has been difficult to obtain zeolites with varied pore sizes. The usefulness of zeolites as catalytic materials is limited to small organic molecules. Unlike zeolites, CPs can be synthesized with linkers of varying sizes, linking metals of different coordination environments, to give an array of porous materials with diverse channel shapes and sizes. Due to their chemical variety,
CPs can be tailored to catalyze certain reactions under milder conditions compared to zeolites. Their channel size can be modified using different organic linkers to catalyze
reactions for substrates which are too large for zeolitic pores.
1.5.2. Catalytic Sites in Coordination Polymers
Catalytic sites in CPs can be generated in several ways. First, evacuating the
framework of coordinated solvent molecules will leave open metal sites that can act as
Lewis acid catalytic sites. Second, a functionalized organic linker, that has an attached
catalytic site, can be incorporated. Last, a material can be incorporated in the channel
(catenation) of the CP, which can act as the catalytic center for the material. In the
literature, there has been some confusion as to whether a CP is acting as the catalyst or
11 whether some homogeneous material dissolved in solution is catalyzing the reaction.
Control experiments can be run in which the catalyst is filtered off after a certain time period, and the filtrate can be monitored to see if catalysis persists. Also, there is some debate over whether catalysis is occurring in the channels of the CP or on the surface of the CP. Experiments have been conducted in which the size of the substrate was increased to a dimension greater than the size of the cavity. There should be no catalysis observed for these molecules which can not fit in the cavities of the framework.
1.5.3. Catalytic Reactions using Coordination Polymers
1.5.3.1 Cyanosilylation of Aldehydes
Fujita and co-workers found that a cadmium-based CP, [Cd(L)(H2O)2](NO3) (L =
4,4’-bipyridine), showed the ability to catalyze the cyanosilylation of aldehydes (Scheme
1).99 In particular, benzaldehyde was converted to 2-(trimethylsiloxy)phenylacetonitrile
in 77% yield. The framework was made up of an octahedral Cd (II) metal center linked
by four 4,4’-bipyridine units in the equatorial positions to form a two-dimensional 4,4-
network. The axial positions on the Cd metal center were occupied by water molecules
which were removed from the layers under vacuum. To investigate whether the CP
O OSiMe3 CN CP H H + Me3SiCN CH2Cl2
Scheme 1: The cyanosilylation of aldehydes using a coordination polymer (CP) as a
heterogeneous catalyst.
12 was acting as the catalyst, it was filtered from the reaction mixture and the filtrate was allowed to stand. No further conversion was seen, indicating the CP was acting as the catalyst for the reaction. The CP showed some selectivity to substrate. This selectivity was due to the limited cavity size of the material. The catalyst was more active towards
2-Tolualdehyde than 3-tolualdehyde, while there was no conversion shown for 9- anthraldehyde. The catalytic sites also showed preference for ortho-dihalobenzenes as opposed to the meta or para isomers. This supported the author’s conclusion that the catalytic sites can be selective towards different substrates.
Similar cyanosilylation reactions have been carried out with other coordination
100 polymers. [Cu3(BTC)2(H2O)3] (BTC: 1,3,5-benzenetricarboxylate) is a 3D coordination polymer built on copper paddlewheel building blocks linked by 1,3,5- benzenetricarboxylate ligands. Water molecules occupied the axial positions and were removed under vacuum to give the activated catalyst. The framework showed permanent porosity, which was confirmed by surface area measurements. The copper center coordinates to the aldehyde and promotes the reaction. The framework showed little conversion to the cyanosilyl product at room temperature (<5%); however, when the temperature was raised to 45oC, a 57% conversion to the product was observed.
Long and co-workers showed that a Mn(II)-based CP (Mn3[(Mn4Cl)3(BTT)8
(CH3OH)10]2 (H3BTT: 1,3,5-benzenetristetrazol-5-yl)) can efficiently catalyze the cyanosilylation of aldehydes.101 The framework catalyzed the transformation of benzaldehyde in 98% yield at RT after nine hours, which was an improvement over previous frameworks studied.99-100
13 Some limitations were seen when using CPs as heterogeneous catalysts with
transition metal-based CPs. If an electron-donating solvent was used during the reaction,
it could compete with the aldehyde for coordination to the metal center and no product
was observed. Also, some of the CPs could not be heated above a certain temperature
(50oC) or decomposition of the framework resulted.
Lanthanide-based CPs have also been used as Lewis acid catalysts in the reaction
involving the cyanosilylation of aldehydes. The Gd framework, [Gd(L-H2)(L-H3)(H2O)4]
(L = 2,2’-diethoxy-1,1’-binaphthalene-6,6’-bisphosphonic acid), built on bisphosphonate
ligands, adopted a 2D lamellar structure, which exhibits permanent porosity and can
catalyze the cyanosilylation of aldehydes in moderate yields (55-61 %).102 Results indicate that the framework swells to incorporate the substrate into its structure and promote the catalysis.
1.5.3.2 The Biginelli Reaction
Another organic reaction that uses the Lewis acid sites on the metal ion for catalysis is known as the Biginelli reaction. The Biginelli reaction involves the cyclocondensation of an aldehyde, a dicarbonyl compound and urea in the presence of a catalytic amount of a Lewis acid to give a substituted dihydropyrimidinone (Scheme 2).
H R N O O O O O CP 1 + + +H2O H N NH Toluene or MeOH O N R1 H 2 2 O H O R1 =aryl
Scheme 2: The Biginelli reaction using a CP as a heterogeneous catalyst.
14 Dihydropyrimidinones and their derivatives have long been known to have important
pharmacological properties as anti-virals103 as well as other related medicinal
applications.104-106 The Biginelli reaction has been used to assess the catalytic properties
of rare earth frameworks in several studies.107-109 Lii and co-workers108 explored
[Gd(H2O)(C2O4)0.5(HPO3)] · H2O as a potential heterogeneous catalyst in the Biginelli
reaction. The CP was mixed with benzaldehyde, ethyl acetoacetate and urea in methanol
at room temperature with stirring for 3 days. The framework showed 52% conversion to
5-ethoxycarbonyl-6-methyl-4-phenyl-3,4-dihydro-pyrimidin-2(1H)-one. This result is
107 similar to those of Bao and co-workers, who used [Gd(C9N3H2O(PO3H)2
(PO3))(H2O)]ClO4·3H2O as a catalyst and obtained 68% conversion to the Biginelli
product under similar conditions.
109 Lii and co-workers also explored a new material, (H4APPIP)[Yb3(C2O4)5.5
(H2PO4)2] ·5H2O, for use as a catalyst in the Biginelli reaction under similar conditions.
The yield was considerably lower (27%) due to the catalysis taking place on the surface
and not in the channels of the framework.
1.5.3.3 The Knoevenagel Condensation
There are many examples of CPs catalyzing organic reactions using the available
Lewis acid sites on the metal ion. A second approach is functionalizing the organic linker
and using the linker as the catalytic site, instead of the metal center. This can be useful
when the organic linkers are bulky and the substrate’s availability to the metal centers is prohibited. The synthesis can occur in one of two ways. First, one can utilize a functionalized organic linker and carry it through the framework synthesis from the
15 beginning; conversely, one can synthesize the framework and then post-synthetically
modify the linker in a subsequent reaction.
Hasegawa and co-workers110 reported a 3D CP based on octahedral Cd metal
centers coordinated by amide functionalized 1,3,5-benzenetricarboxylic acid linkers
. . {[Cd(4-btapa)2 (NO3)2] 6H2O 2DMF} (4-btapa =1,3,5-benzenetricarboxylic acid tris[N-
(4-pyrid-yl)amide]). They showed that the amide sites on the linker, which were
protruding into the channels, can catalyze a weakly basic organic reaction known as the
Knoevenagal condensation (Scheme 3).
O NC R CP H + RCH2CN H benzene
Scheme 3: The Knoevenagel condensation reaction using a CP as a heterogeneous
catalyst.
The CP contained three-dimensional pores that were 4.7 x 7.3 Å in size. Their
group showed that, if the size of the cyano substrate is changed from malononitrile (6.9 x
4.5 Å) to ethyl cyanoacetate (10.3 x 4.5 Å), and finally cyanoacetic acid tert-butyl ester
(10.3 x 5.8 Å), the catalytic activity decreased dramatically. This indicated that the
catalysis is occurring in the channels of the CP and not on the surface.
Gascon and co-workers111 synthesized an amino-functionalized CP based on 2-
aminoterephthalic acid and Zn metal ions (IRMOF-3), which was first reported by
Yaghi’s group.112 They showed that IRMOF-3 had catalytic activity in the Knoevenagel
condensation, with yields of 99% after 2 hours when ethyl cyanoacetate and
16 benzaldehyde were used as the substrates. The IRMOF-3 catalyst was stable under the reaction conditions and could be reused without loss of catalytic activity.
Research Goal
The goal of this research is to synthesize and characterize a variety of lanthanide based coordination polymers. The coordination polymers will be based on commercially available organic linkers such as 2,5-thiophenedicarboxylic acid (2,5-TDC) and 2,3,5,6- tetrafluoro-1,4-terephthalic acid (F4BDC), which vary in their acid/base properties. The
slightly basic 2,5-TDC molecules will potentially form a framework that is more basic
than a framework based on the less basic linker, F4BDC. The compounds will be
completely characterized by single crystal x-ray diffraction and x-ray powder diffraction
along with thermogravimetric analysis and infrared spectroscopy. The luminescence
properties of the CPs will be studied along with the catalytic properties of the CPs in
some common organic reactions. Addition of fluorine-based functional groups to the
organic linker may decrease the pore size of the CPs. With this reduction in pore size, a
size selective catalyst will ensue. The F4BDC linker will potentially give a framework
with greater Lewis acid catalytic activity due to the electron withdrawing fluorine atoms
pulling electron density away from the lanthanide, making it more electropositive. The
Lewis acid catalyzed reaction chosen for this study is the Biginelli reaction.
17 CHAPTER 2: EXPERIMENTAL
2.1. Materials
EuCl3 (anhyd), La(NO3)3·6H2O, Gd(NO3)3·6H2O, and Eu(NO3)3·6H2O were purchased from Johnson Matthey (Savannah, GA). 2,5-Thiophenedicarboxylic acid, N,N- dimethylformamide, Nd(NO3)3·5H2O, Tb(NO3)3·5H2O, triethylamine, n-formyl
piperidine, acetic anhydride, potassium hydroxide, sodium bicarbonate, benzaldehyde and ethyl acetoacetate, acetonitrile, chloroform-d, DMSO-d6 and n-propanol were
purchased from Sigma-Aldrich Chemical Co (Milwaukee, WI). 2,3,5,6-Tetrafluoro-1,4- benzenedicarboxylic acid and 2,3,4,5-tetrabromothiophene were obtained from Matrix
Scientific Co (Columbia, SC). Urea, hexanes, ethyl acetate, ethyl-2-mercaptoacetate, m- xylene, n-butyllithium in hexanes (1.6M), anhydrous diethyl ether and N,N- diethylformamide (DEF) were obtained from Acros Chemical Co (Pittsburgh, PA).
Ethanol was purchased from Aaper Alcohol and Chemical Co (Shelbyville, KY).
Bromine, CuCl2, Mn(OAc)2, potassium carbonate, iodine, chromium trioxide,
concentrated sulfuric acid, concentrated acetic acid, concentrated hydrochloric acid,
toluene and methanol were purchased from Fisher Chemical Co (Milwaukee, WI).
Acetone-d6 and acetonitrile-d3 were obtained from Cambridge Isotope Labs Inc (Andover,
MA). HPLC grade acetonitrile was distilled prior to use. All other solvents were used as
received without further purification.
18 2.2. Methods
2.2.1. Analytical Methods
1H and 13C-NMR spectra were recorded on Bruker Avance DPX-300 and DPX-
500 NMR sprectrometers. Thermogravimetric analysis (weight between 5 and 20 mg) was performed under air (40 mL/min) at a rate of 5oC/min from 40-900oC using a Perkin-
Elmer Pyris 1 TGA system. Infrared spectra were recorded over the 450-4000 cm-1 region
using KBr pellets on a Mattson Infinity FT-IR spectrometer or on a Perkin Elmer
Spectrum 100 spectrophotometer with an ATR sampling accessory equipped with a diamond anvil. Elemental analyses were carried out by Atlantic Microlabs, Inc (Norcross,
GA). GC-MS data were recorded on an Agilent 6850 Series GC system coupled to an
Agilent 5973 Mass Selective Detector run in electron impact mode. A 50-split method was chosen to run on an Agilent column (13 x 0.25 mm x 0.25 μm) at a ramp rate of
13oC/min from 50oC to 280oC. Solid state photoluminescence spectra were recorded on
an Alphascan fluorimeter from Photon Technologies International. The light source was a
150-W Xenon arc lamp with a Hamamatsu R666S photomultiplier tube.
2.2.2. X-Ray Diffraction Methods
Crystals suitable for single crystal x-ray diffraction were microscopically
examined, selected from solution and held on a slide cooled with dry ice to minimize loss
of solvent. Three dimensional intensity data for all compounds were measured on a
Bruker SMART APEX CCD area detector system at 193 K using Mokα radiation (λ =
0.7107Å). Data was corrected for absorption effects using the SADABS program.113 All
19 structures were determined and refined using the Bruker SHELXTL software package
(Version 6.1).114
X-Ray powder diffraction data were collected at room temperature using a
BRUKER P4 general-purpose four-circle X-ray diffractometer modified with a
GADDS/Hi-Star detector at 40 kv and 30 mA for Cukα radiation (λ = 1.5406Å). GADDS software suite was used to control the goniometer.115 The samples were mounted on tape and three frames were measured at 2θ = 5.2o, 28o and 48o with exposure time of 360 seconds/frame. The powder patterns were each merged and analyzed using the EVA program to produce a single powder diffraction pattern.116 The simulated powder patterns were calculated using Mercury Software for Windows.
2.3. Synthesis
2.3.1 Solvothermal Method
. Preparation of La2(2,5-TDC)3(DMF)2(H2O) DMF (1).
La(NO3)3 · 6H2O (66.2 mg, 0.152 mmol) and 2,5-thiophenedicarboxylic acid
(20.0 mg, 0.116 mmol) were added to a Pyrex tube containing DMF (0.75 mL) and n- propanol (1 mL). The tube was frozen in a liquid nitrogen bath, flame-sealed under vacuum, and heated to 105oC for 24 hours. The mixture was allowed to cool to room temperature slowly at a rate of 2oC/min. The mixture was decanted, vacuum filtered, and washed with DMF and ether to yield a colorless crystalline product which was allowed to dry in air. Yield (21.4 mg, 58 %, based on 2,5-TDC). FT-IR (KBr): 3463 (br), 3087 (w),
2932 (w), 1666 (s), 1565 (br), 1525 (s), 1382 (s), 1110 (m), 1036 (m), 816 (m), 776 (s),
20 672 (m), 465 (s). Anal. Calc’d for C24H22La2N2O15S3: C, 30.26; H, 2.32; N, 2.94; Found:
C, 30.45; H, 2.39 ; N, 3.28.
Preparation of Gd2(2,5-TDC)3(DMF)2H2O (2).
The procedure was similar to that used for 1 with Gd(NO3)3 ·6H2O (58.4 mg,
0.129 mmol) and 2,5-TDC (11.1 mg, 0.0640 mmol) yielding a colorless crystalline product Yield (19.4 mg, 92 %, based on 2,5-TDC). FT-IR (KBr): 3430 (br), 3118 (w),
2935 (w), 1669 (s), 1577 (br), 1531 (s), 1385 (br), 1107 (w), 801 (w), 775 (s), 677 (m),
474 (m). Anal. Calc’d for C24H22Gd2N2O15S3: C, 29.14; H, 2.24; N, 2.83; Found: C,
28.87; H, 2.14; N, 3.01.
Preparation of Eu4(2,5-TDC)6(DMF)3(H2O)2(H2O/n-prOH) (3).
The procedure was similar to that used for 1 with EuCl3 (60.0 mg, 0232 mmol) and 2,5-TDC (11.5 mg, 0.132 mmol) yielding a colorless crystalline product. Yield (34.6 mg, 81 %, based on 2,5-TDC). FT-IR (KBr): 3457 (br), 3094 (w), 2935 (w), 1669 (s),
1599 (br), 1526 (s), 1437 (s), 1372 (br), 1103 (w), 1036 (w), 819 (w), 776 (s), 682 (m),
471 (m). Anal Calc’d for C24H20Eu2N2O14S3: C, 26.27; H, 2.10; N, 2.91; Found: C, 26.38;
H, 2.19; N, 2.71;
Preparation of Y(2,5-TDC)(DMF)2NO3 (4)
The procedure was similar to that used for 1 with Y(NO3)3·6H2O (95.7 mg, 0.262 mmol) and 2,5-TDC (12.0 mg, 0.0697 mmol) yielding a crystalline product. Yield (19.4 mg, 59 %, based on 2,5-TDC). FT-IR (KBr): 3457 (br), 3099 (w), 2939 (w), 1679 (br),
1531 (st), 1398 (br), 1110 (m), 1033 (w), 800 (w), 777 (s), 680 (m), 474 (m). Anal Calc’d for C12H16N3O9SY: C, 30.85; H, 3.45; N, 2.91; Found: C, 28.67; H, 2.68;
21 2.3.2 Reflux Method
. Preparation of La2(2,5-TDC)3(DMF)2(H2O) DMF (1).
To a 10 mL 2-neck round-bottom flask equipped with a reflux condenser and a
stopper was added La(NO3)3 · 6H2O (216.4 mg, 0.520 mmol), 2,5-TDC (46.0 mg, 0.268
mmol), DMF (3 mL), and n-propanol (4 mL). After the contents dissolved, the stir bar
was removed and glass beads were added. The solution was flushed with argon and set to
reflux under argon for 15 h at 125oC. A colorless microcrystalline product appeared and was separated by decanting the solvent. The product was filtered and washed with DMF and diethyl ether. Yield (70 mg, 76 %, based on 2,5-TDC). FT-IR (KBr): 3500 (br), 3097
(w), 2935 (w), 1670 (s), 1575 (br), 1525 (s), 1394 (s), 1105 (m), 1035 (m), 817 (m), 773
o (s), 676 (m), 464 (s). La2(2,5-TDC)3(DMF)n (1a) was formed by heating at 5 C/min to
250oC and holding for 1 hour. The evacuated framework was brought back to RT at
5oC/min and stored over argon until use.
Preparation of Gd2(2,5-TDC)3(DMF)2H2O (2).
The procedure was similar to that used for 1 with Gd(NO3)3 · 6H2O (247.6 mg,
0.549 mmol) and 2,5-TDC (60.6 mg, 0.352 mmol) which gave a colorless microcrystalline product. Yield (100.9 mg, 87 %, based on 2,5-TDC). FT-IR (KBr): 3438
(br), 3119 (w), 2940 (w), 1669 (s), 1577 (s), 1531 (s), 1385 (br), 1107 (w), 794 (w), 775
o (s), 677 (m), 472 (m). Gd2(2,5-TDC)3(DMF)n (2a) was formed by heating at 5 C/min to
250oC and holding for 1 hour. The evacuated framework was brought back to RT at
5oC/min and stored over argon until use.
22 Preparation of Eu4(2,5-TDC)6(DMF)3(H2O)2(H2O/n-prOH) (3)
The procedure was similar to that used for 1 with EuCl3 (74.8 mg, 0.290 mmol)
and 2,5-TDC (22.4 mg, 0.130 mmol) yielding a colorless microcrystalline product. Yield
(35.4 mg, 84 %, based on 2,5-TDC). FT-IR (KBr): 3475 (br), 3097 (w), 2936 (w), 1671
(s), 1599 (br), 1541 (s), 1437 (s), 1386 (br), 1108 (w), 1039 (w), 818 (w), 782 (s), 678
(m), 474 (m).
Preparation of Y(2,5-TDC)(DMF)2NO3 (4).
The procedure was similar to that used for 1 with Y(NO3)3·5H2O (365.8 mg, 1.00
mmol) and 2,5-TDC (54.2 mg, 0.3148 mmol) yielding a white microcrystalline product.
Yield (72.9 mg, 49.5 %, based on 2,5-TDC). FT-IR (KBr): 3450 (br), 3113 (w), 2944 (w),
1674 (s), 1583 (br), 1529 (s), 1386 (s), 1109 (w), 774 (s), 681 (m), 475 (m).
2.3.3. Vapor Diffusion Method
. Preparation of Tb2(F4BDC)3(DEF)2(EtOH)2 2 DEF (5)
Tb(NO3)3·5H2O (54.2 mg, 0.125 mmol) and H2F4BDC acid (41.8 mg, 0.176
mmol) were added to a 10 mL vial containing N’N-diethylformamide (6 mL) and
ethanol (1 mL) and dissolved. The vial was covered with parafilm which was pierced
several times with a needle and set inside a beaker containing ethanol (5 mL) and
triethylamine (0.2 mL). The beaker was then covered with parafilm and the mixture of
ethanol and triethylamine vapor was allowed to diffuse into the solution for a period of
48 hr. A white crystalline product formed which was washed with DEF and acetone and
allowed to dry in air. Yield: (44.7 mg, 52 %, based on F4BDC). Anal. Calc’d for
Tb2(F4BDC)3(DEF)2(EtOH)2-1.5(DEF): C, 37.12; H, 3.46. Found: C, 37.06; H, 3.52. FT-
23 IR (KBr): 3450 (br), 2989 (w), 2950 (w), 1652 (s), 1614(s), 1481 (s), 1411 (br), 1268 (m),
1216(m), 1128 (m), 995 (s), 827 (w), 738 (s), 661 (m), 480 (m).
. Preparation of Gd2(F4BDC)3(DEF)2(EtOH)2 2 DEF (6)
A similar procedure to that used for 5 with Gd(NO3)3·6H2O (88.7 mg, 0.196
mmol) and F4BDC (35.4 mg, 0.149 mmol) gave a white crystalline product. Yield (47.2 mg, 61 %, based on F4BDC). Anal. Calc’d (%) for Gd2(F4BDC)3(DEF)2(EtOH)2: C,
34.61; H, 2.60. Found: C, 34.95; H, 2.61. FT-IR (KBr): 3448 (br), 2989 (w), 2952 (w),
1648 (s), 1614(s), 1481 (s), 1411 (br), 1268 (m), 1214(m), 1128 (m), 983 (s), 827 (w),
738 (s), 659 (m), 478 (m).
. Preparation of Eu2(F4BDC)3(DEF)2(EtOH)2 2 DEF (7)
A similar procedure to that used for 5 with Eu(NO3)3·5H2O (55.4 mg, 0.124
mmol) and F4BDC (40.4 mg, 0.170 mmol) gave a white crystalline product. Yield (48.5 mg, 64 %, based on F4BDC). Anal. Calc’d for Eu2(F4BDC)3(DEF)2(EtOH)2-0.4(DEF): C,
35.67 ; H, 2.87. Found: C, 35.63; H, 2.61. FT-IR (KBr): 3459 (br), 2996 (w), 2958 (w),
1648 (s), 1614(s), 1473 (s), 1413 (br), 1270 (m), 1216(m), 1128 (m), 995 (s), 827 (w),
788 (m), 750 (m), 659 (m), 480 (m). Eu2(F4BDC)3(DEF)n (7a) was formed by heating at
5oC/min to 150oC and holding for 1 hour. The evacuated framework was brought back to
RT at 5oC/min and stored over argon until use.
. Preparation of La2(F4BDC)3(DEF)2(EtOH)2 2 DEF (8)
A similar procedure to that used for 5 with La(NO3)3·6H2O (64.0 mg, 0.148
mmol) and F4BDC (50.0 mg, 0.212 mmol) gave a white crystalline product. Yield (46.0 mg, 49 %, based on F4BDC). Anal. Calc’d for La2(F4BDC)3(DEF)2(EtOH)2-0.5(DEF): C,
36.54; H, 2.99. Found: C, 36.56; H, 2.82. FT-IR (KBr): 3436 (br), 2989 (w), 2950 (w),
24 1648 (s), 1614(s), 1475 (s), 1405 (br), 1268 (m), 1214(m), 1128 (m), 995 (s), 827 (w),
748 (s), 655 (m), 474 (m).
. Preparation of Nd2(F4BDC)3(DEF)2(EtOH)2 2 DEF (9)
A similar procedure to that used for 5 with Nd(NO3)3·6H2O (78.4 mg, 0.179
mmol) and F4BDC (52.8 mg, 0.222 mmol) gave a white crystalline product. Yield (47.7 mg, 45 %, based on F4BDC). Anal. Calc’d for Nd2(F4BDC)3(DEF)2(EtOH)2-1.5(DEF): C,
37.87; H, 3.53. Found: C, 37.86; H, 3.52. FT-IR (KBr): 3446 (br), 2985 (w), 2950 (w),
1654 (s), 1616 (s), 1475 (s), 1409 (br), 1268 (m), 1214 (m), 1128 (m), 995 (s), 827 (w),
748 (s), 657 (m), 476 (m).
2.3.4. Catalytic Experiments
2.3.4.1. Heterogeneous Catalysis
Preparation of 5-(Ethoxycarbonyl)-6-methyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-
one (10a)
Benzaldehyde (30 μL, 0.29 mmol), ethyl acetoacetate (35 μL, 0.28 mmol), urea
(30.0 mg, 0.49 mmol), 7a (21.8 mg, 0.014 mmol) and toluene (0.2 mL) were added to a
10 mL round-bottom flask equipped with a reflux condenser. The mixture was heated to
80oC for 1.5 hours, then cooled to RT and diluted with ethyl acetate. The catalyst was
filtered off and the ethyl acetate solution was washed with water (2 ×15 mL). The organic
phase was dried over MgSO4, filtered, and evaporated to give the crude product. The
product was purified by trituration in an ethyl acetate/petroleum ether solution to give
10a. Yield (40.5 mg, 50 %). FT-IR (KBr): 3230, 3101, 2974, 2918, 1713, 1697, 1642,
1465, 1418, 1341, 1313, 1291, 1218, 1085, 950, 771. 1H-NMR (DMSO), δ (ppm): 9.17 (s,
25 1H, NH); 7.71 (s, 1H, NH); 7.28 (m, 5H, Ar-H); 5.14 (d, 1H, CH); 3.98 (q, 2H, OCH2);
+ 2.25 (s, 3H, CH3); 1.10 (t, 3H, OCH2). GC-MS (m/e, %): 260 [parent M ] (19); 231 (75);
214 (13); 183 (100); 155 (40); 137 (25); 110 (8); 77 (11); 40 (16).
Room temperature reactions followed the same procedure but, instead of heating,
the solution was stirred for three days at ambient temperature in toluene or MeOH (see
Table 3).
Preparation of 5-(Ethoxycarbonyl)-6-methyl-4-(3-thienyl)-3,4-dihydropyrimidin-
2(1H)-one (10b)
The procedure was similar to that used for 10a with 3-thiophenecarboxaldehyde
(60 μL, 0.29 mmol) in toluene (1 mL). The product was recrystallized from ethanol to
give 10b.Yield (29.6 mg, 13 %). FT-IR (KBr): 3220, 3096, 2968, 1720, 1697, 1645, 1457,
1419, 1369, 1319, 1291, 1228, 1086, 950, 763. 1H-NMR (DMSO), δ (ppm): 9.18 (s, 1H,
NH); 7.74 (s, 1H, NH); 7.45 (m, 1H, Ar-H); 7.15 (s, 1H, Ar-H); 6.98 (d, 1H, Ar-H); 5.21
(d, 1H, CH); 4.05 (q, 2H, OCH2); 2.22 (s, 3H, CH3); 1.15 (t, 3H, OCH2). GC-MS
(m/e, %): 266 [parent M+] (86); 237 (80); 219 (20); 193 (100); 183 (49); 155 (32); 137
(31); 110 (25); 40 (36).
Preparation of 5-(Ethoxycarbonyl)-6-methyl-4-(1-napthyl)-3,4-dihydropyrimidin-
2(1H)-one (10c)
The procedure was similar to that used for 10a with 1-napthylenecarboxaldehyde
(76 μL, 0.29 mmol) in toluene (1 mL) gave compound 10c after recrystallization from ethanol. Yield (17.5 mg, 12 %). FT-IR (KBr): 3232, 3099, 2975, 2920, 1696, 1644, 1512,
1 1430, 1376, 1318, 1279, 1267, 1219, 1086, 1025, 949, 766. H-NMR (DMSO-d6): δ =
9.24 (s, 1H, NH); 8.30 (d, 1H, Ar-H); 7.95 (d, 1H, Ar-H); 7.85 (d, 1H, Ar-H); 7.73 (s, 1H,
26 NH); 7.55 (m, 4H, Ar-H); 6.05 (s, 1H, CH); 3.80 (q, 2H, OCH2); 2.36 (s, 3H, CH3); 0.81
(t, 3H, OCH2).
2.3.4.2. Homogeneous Catalysis
Preparation of 5-(Ethoxycarbonyl)-6-methyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-
one (10a)
Benzaldehyde (50 μL, 0.49 mmol), ethyl acetoacetate (62 μL, 0.49 mmol), urea
(49.1 mg, 0.81 mmol), 7a (33.3 mg, 0.022 mmol) and water (0.5 mL) were added to a 10
mL round- bottom flask. The solution was stirred at ambient temperature for 3 days after
which the reaction mixture was diluted with ethyl acetate (10 mL) and washed with water
(2 × 15 mL). The organic phase was dried over MgSO4, filtered, and evaporated to give
the crude product. The product was purified by filtration of an ethyl acetate/petroleum
ether solution to give pure 10a. Characterization was by methods similar to that above.
27 CHAPTER 3
SYNTHESIS, CRYSTAL STRUCTURE AND PROPERTIES
OF COORDINATION POLYMERS 1-4
Christopher M. MacNeill, Cynthia S. Day, Sergio A. Gamboa, Abdessadek Lachgar and
Ronald E. Noftle
A section of this chapter was excerpted from a published manuscript in the Journal of
Chemical Crystallography, 2010, volume 40, pages 222-230, and is reprinted with permission from the journal. All of the research presented was conducted by Christopher
M. MacNeill with help from Sergio A. Gamboa. Crystal Structure Data was compiled by
Cynthia S. Day. The manuscript was prepared by Christopher M. MacNeill and edited by
Abdessadek Lachgar and Ronald E. Noftle.
28 3.1 Synthesis of Coordination Polymers 1-4
A solvothermal method was employed in the synthesis of coordination polymers
1-4. Stoichiometric ratios of 4:1 and 2:1 lanthanide metal to 2,5-TDC were employed for
1-4 and in each case the same overall three-dimensional coordination polymer resulted.
Because of this, the use of 2:1 ratios of lanthanide metal to organic linker was chosen to
conserve linker.
In the course of our work, we discovered that the coordination polymers 1-4 could also be prepared in bulk using a benchtop reflux method. In the case of the reflux method, product was visible after 15 hr at 125oC. Slow cooling in this case was defined as
dropping the temperature by 20oC over ten minutes. Prepared in this manner, the product was microcrystalline but, nevertheless, it retained the basic framework structure as shown by comparison of the powder diffraction spectra with those for the products prepared solvothermally (Appendix B4-B6).
In the case of both methods, the pH of the system was not adjusted. DMF was the preferred solvent owing to the solubility of 2,5-TDC. N-Propanol was also chosen as solvent due to enhanced crystal growth compared to that in DMF/H2O mixtures
3.2. Single Crystal X-Ray Diffraction
3.2.1. Crystal structure of La2(2,5-TDC)3(DMF)2H2O · DMF (1)
Compound 1 crystallizes in the orthorhombic space group Pna21 (no. 33). The
coordination polymer is built on lanthanum ions linked by TDC2- ligands. The asymmetric unit contains two crystallographically different lanthanum ions (La(1) and
La(2)), three TDC2- ligands, two DMF molecules, one water molecule and one lattice
29 DMF molecule. The La(1) ion is eight-coordinated by six monodentate oxygen atoms
(O(12), O(21), O(13), O(31) and O(23)) from five different TDC2- ligands, one bidentate
(O(33) and O(34)) TDC2- ligand and an oxygen atom from a DMF molecule (Figure 4a).
(a) (b)
Figure 4: Coordination environment around (a) La3+(1) and (b) La3+(2) ion.
The La-O bond lengths range from 2.392(7) Å and 2.562(9) Å, which is comparable to
other La-O bond distances.117-118 The larger bond length (2.869(6) Å) for O(34) is
2- attributed to the μ3-TDC coordination mode that is seen with other lanthanum-based
coordination polymers.119 The coordination environment around La(2) consists of six
oxygen atoms from six TDC2- (O(11), O(14), O(22), O(24),O(32), and O(34)) with bond
lengths between 2.430(6) Å and 2.569(6) Å, one oxygen (O(2)) from DMF with La(2)-
O(2) = 2.587(7) Å) and one oxygen (O(4)) from the water molecule with La(2)-O(4) =
2.674(5) Å) (Figure 4b). The two lanthanum ions are linked by the carboxylate oxygen atoms from four TDC2- ligands to form dimers with La(1)-La(2) distances of 4.2678(9) Å
(Figure 5a).
30
(a) (b)
- Figure 5: (a) The La(1)-La(2) dimer formed by four bridging TDC2- linkages. (b) A chain
formed through linking of dimers from coordination polymer 1 shown down the a-axis.
The La environment is shown as teal polyhedra, O (red), C (grey), S (yellow).
The dimers are connected by two TDC2- ligands through (O(21), O(22), O(31)
and O(32)) to form distorted chains along the crystallographic a-axis (Figure 5b). Two
planes were drawn through La(1) and La(2) atoms along the a-axis and the angle between
those planes is 124.61o. The torsion angle for (La(1)-La(2)-La(1)-La(2)) is 0.838o, which means the lanthanum ions in the chain do not lie directly on-top of each other if viewed down the a-axis. The La-O bond lengths for this linkage range from 2.400(6) Å for
La(1)-O(21) to 2.540(7) Å for La(2)-O(22).
Each chain is linked to four adjacent chains via the oxygen atoms from four
TDC2- ligands to form a neutral three-dimensional 4,4- network with large diamond
shaped channels (6.7 X 6.7 Å) along the a-axis, where the DMF and water molecules
are located (Figure 6).
31
Figure 6: A perspective view of coordination polymer 1 along the a-axis with solvent
molecules omitted for clarity.
3.2.2. Crystal structure of Gd2(2,5-TDC)3(DMF)2H2O (2)
Compound (2) crystallizes in a monoclinic P21/n space group and forms an
overall neutral 3D coordination network that is very similar to that of compound 1. The
asymmetric unit contains two gadolinium ions, three TDC2- ligands, two DMF molecules
and one water molecule. The gadolinium ion Gd(1) is eight-coordinate and attached to
five TDC2- oxygen atoms (O(3a), O(4a), O(4b) O(2a), O(1)), one bidentate TDC2- (O(3b),
O(4b)), and one oxygen atom (O(5)) from the terminal DMF molecule (Figure 7a). The
Gd(1)-O distances of the TDC2- ligand range from 2.3061 Å to 2.4399 Å, which is in
agreement with those in the literature.120-121 The bond distances for the bidentate TDC2-
(O(4b)-Gd(1)-O(3b)) are 2.5879(59) Å and 2.4399(57) Å, respectively.
32
(a) (b)
Figure 7: The coordination environments around the (a) Gd3+(1) and (b) Gd3+(2) ion.
The corresponding gadolinium ion Gd(2) is eight-coordinate with six TDC2- bridging oxygen atoms (O(1a), O(1b), O(2), O(4), O(2b), O(3)), one oxygen (O(6)) from the terminal DMF molecule and one oxygen (H2(O7)) from a terminal water molecule
(Figure 7b). The Gd(2)-O distances of TDC2- ligands range from 2.3024 Å to 2.4495 Å.
The Gd-ODMF distances for Gd(1)-O(5) and Gd(2)-O(6) are 2.3732(55) Å and 2.4495(55)
Å, respectively. The Gd(2)-H2(O7) distance is 2.6447(68) Å.
The two gadolinium ions are coordinated by four TDC2- ligands to form two different dimers (Figure 8a and 8b) along the a-axis with a distance between adjacent gadolinium ions (Gd(1)-Gd(2)) of 5.2740(5) Å. The dimers are further bridged by two
TDC2- ligands to form a distorted chain along the a-axis, similar to framework (1) (Figure
8c).
33
(a) (b)
(c)
Figure 8: (a) The Gd(1)-Gd(1) dimer formed by four bridging TDC2- linkages. (b) The
Gd(2)-Gd(2) dimer formed by four bridging TDC2- linkages. (c) A chain formed through linking of dimers 1 and 2 down the a-axis for coordination polymer 2. The Gd environment is shown as blue polyhedra.
34 3.2.3. Crystal structure of Eu4(2,5-TDC)6(DMF)3(H2O)2(H2O/n-prOH) (3)
Compound 3 is a neutral 3D coordination polymer that crystallizes in the
monoclinic Pc space group. The asymmetric unit contains four europium atoms, six
TDC2- ligands, three DMF molecules, two water molecules and one disordered
coordinated solvent molecule that is a 50:50 occupancy of water/n-propanol. The
europium atoms are both 8-coordinate and bound to six TDC2- ligands, one terminal
2- DMF molecule, and H2O molecule (Figure 9). The Eu-O bond distances for the TDC ligands range from 2.2906(8) Å to 2.5126(8) Å while the Eu-ODMF distances are
2.3713(10) Å and 2.4692(10) Å, respectively. The lone water molecule (Eu(1)-O(5)-
Eu(2); distances = 2.802(1) Å and 2.5839(9) Å) bridges the two europium atoms (Eu(1)-
Eu(2)) distance = 4.7717(21) Å). The europium atoms (Eu(1) and Eu(2)) are bridged by
two TDC2- ligands and one water molecule forming a dimer along the c-axis (Figure 10a).
These dimers are further bridged by four TDC2- to form a 1D sinusoidal chain along the
c-axis (Figure 10b).
(a) (b)
Figure 9: The coordination environments around the (a) Eu3+(1) ion and (b) Eu3+(2) ion.
35
(a) (b)
Figure 10: (a) The asymmetric unit of Eu(1) and Eu(2) (pink) linked by two TDC2-
(bridging) linkages along with eight TDC2- linkages (all monodentate), two DMF
molecules and one H2O molecule (bridging) forming Eu4(2,5-
TDC)6(DMF)3(H2O)2(H2O/n-prOH) (3). (b) A chain formed through the linking of
dimers in (a) of coordination polymer 3 down the a-axis. Carboxylates are shown in red.
The slight difference in structure between coordination polymers 1, 2, and 3 can
be seen in the environments around the Ln(1) and Ln(2) ions. Also, the bidentate TDC2- coordination mode seen in frameworks 1 and 2 is a monodentate TDC2- coordination
mode in framework 3. Finally, in frameworks 1 and 2, the lone water molecule is bonded
terminally, while in framework 3, the water molecule bridges the two europium ions. The
shorter bond distance between adjacent lanthanide ions in 3 compared to 1 and 2, allows
the water molecule to bridge the ions, instead of coordinating terminally. The overall 3D
topology of 2 and 3 are similar to that of framework 1 (Figure 4). The DMF and H2O/n- propanol molecules occupy the channels of the networks (channel size for 2 = 6.8 X 6.8
36 Å; channel size for 3 = 6.7 X 6.7 Å). The solvent accessible void space was calculated
using PLATON122 and found to be 40.6 % for 1, compared to only 37.4 % for 2.
3.2.4. Crystal structure of Y(2,5-TDC)(DMF)2(NO3) (4)
The structure of framework 4 was solved and refined in the centrosymmetric
space group monoclinic P21/n. Each asymmetric unit contains one Y(2,5-
TDC)(NO3)(DMF)2 repeating unit to form the coordination polymer structure. Each
yttrium atom is 8-coordinate, bound to the oxygens of four TDC2- ligands, two terminal
DMF molecules and one bidentate NO3 molecule (Figure 11a). Each yttrium ion is
bridged by two TDC2- ligands to form a chain down the crystallographic a-axis (Figure
11b). These chains are further bridged through TDC2- ligands to form an overall four-
coordinate irl5 network along the crystallographic a-axis.
a) b)
Figure 11: a). A representation of the environment around the yttrium ion in coordination polymer 4 along the crystallographic ab-plane. b) A view of coordination polymer 4
along the crystallographic a-axis.
37 The μ2-NO3 ion and the disordered DMF molecules occupy the channels formed by the framework. This coordination polymer is isostructural with the only other lanthanide/TDC2- framework reported by Rosi et al.123 The nitrogen and carbon atoms of
both DMF solvent molecules are disordered over two preferred orientations and were
refined with corresponding occupancies of 52 % and 48 %. The overall 3D structure of
coordination polymer 4 is similar to that of coordination polymers 1-3.
3.3. Thermogravimetric Analysis
The stability of frameworks 1-4 was investigated using thermogravimetric
analysis under air from 40oC-900oC at a heating rate of 5oC/min (Figure 12). The
thermogram of 1 exhibits a two-step weight loss between 50 and 400oC. The first weight
120
1 100 2 3
80 4
60 Weight %
40
20
0 0 100 200 300 400 500 600 700 800 900 1000 T (deg)
Figure 12: The TGA curves of coordination polymers 1-4
o loss, between 50 and 150 C, corresponds to the loss of coordinated H2O (observed 2.4 %,
expected 2.0 %). The second, between 200oC and 350oC, corresponds to the loss of two
coordinated DMF molecules (observed 14.1 %, expected 15.2 %). Between 350-375oC,
38 there is a slight weight loss possibly due to the formation of a new unknown phase. The stability of the framework is maintained to 400oC, at which point the weight loss is rapid and the curve is relatively flat to 900oC indicating decomposition of the structure to lanthanide oxide sulfate (LnOSO4) which was assigned by comparing the powder diffraction pattern with that of an authentic sample using a search/match in the EVA program.116 Coordination polymers 2 and 3 showed similar weight losses. The first between 60oC and 110oC corresponds to the loss of coordinated water (2; observed
1.90 %, expected 1.80 %. 3; observed 2.34 %, expected 2.60 %). The second weight loss, between 215oC and 315oC, corresponds to the loss of two coordinated DMF molecules
(2; observed 15.0 %, expected 14.7 %.). The second weight loss in 3 corresponds to loss of two coordinated DMF molecules and loss of coordinated n-prOH (observed 13.0 %, expected 15.0 %). Framework 4 showed a relatively different weight loss than 1-3 because framework 4 has a lower formula weight than 1-3 and also contains a bidentate nitrate group. The thermogram of 4 shows a two-step weight loss between 50 and 400oC.
The first weight loss, between 50 and 100oC, corresponds to the loss of residual solvent.
The second, between 200oC and 350oC, corresponds to the loss of two coordinated DMF molecules (observed 29.1 %, expected 30.2 %). The coordination polymers decompose to
o LnOSO4 (Ln = La, Gd, Eu, Y) at 900 C. The thermograms comparing the solvothermal and reflux methods for coordination polymers 1-3 can be seen in Appendix B1-B3.
3.4. Infrared Spectroscopy
The infrared spectrum (Figure 13) of coordination polymer 1 exhibits a broad peak at 3500 cm-1 which is characteristic of the O-H stretch of the water molecule. The
39 weak vibrations near 3097 cm-1 and 2935 cm-1 correspond to the C-H stretching modes of
the methyl groups of DMF, the ring protons of 2,5-TDC, and the C-H stretching mode of
the aldehyde group on the DMF molecule. The stretching frequency for the carbonyl
group on the thiophene ring of 2,5-TDC, normally seen at 1662 cm-1, was not observed
after coordination to the lanthanide metal, indicating complete deprotonation of 2,5-TDC
to 2,5-TDC2- in both frameworks 1 and 2.124 The asymmetric and symmetric stretching
modes for the carboxylate groups on the thiophene ring occur at 1541-1525 cm-1 and
1398-1372 cm-1. The DMF C=O stretch can be seen at 1666 cm-1, the in-plane and out-
of-plane bending modes of the thiophene ring at 1036 cm-1 and 769 cm-1, and the ring
deformation at 801 cm-1.
120
100 1a 80
60 1
40 % Transmittance no DMF C-H aldehyde or DMF C=O aldehyde 20 stretch in 1a.
0 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Wavenumber (cm-1)
Figure 13: The infrared spectra of coordination polymer 1 at room temperature (RT) and
after heating to 380oC (compound 1a).
A comparison of the IR spectra of compound 1 at RT and after heating to 410oC is shown in Figure 13. The characteristic DMF C-H aldehyde stretch and C=O stretch at
40 2932 cm-1 and 1666 cm-1 which are apparent at room temperature, are no longer seen
after heating to 380oC, indicating loss of DMF from the channels. The metal-carboxylate
(M-O-C) asymmetric and symmetric stretching vibrations at 1525 cm-1 and 1382 cm-1 are still present along with the C-H stretches of thiophene ring protons at 3087 cm-1, the in-
plane and out-of-plane bending modes of the thiophene ring (1036 cm-1 and 776 cm-1) and the ring deformation also (816 cm-1). Similar results are seen for coordination
polymers 3-4 when heated to temperatures between 350-410oC.
400 RT 380o C 900o C 300
200
Intensity
100
0
0 102030405060 2 degree
Figure 14: X-ray powder diffraction spectra comparing the room temperature pattern to
the patterns at 380oC and 900oC of coordination polymer 1.
Figure 14 shows a powder diffraction comparison of framework 1 at room
temperature, when heated to 380oC, and when heated to 900oC. Peaks at 2θ = 24o and 34o at 380oC support the conclusion from the thermogravimetric analysis section, that their is
a formation of a new phase between 350-375oC. The peak at 2θ = 11o for the RT powder
pattern of (1) shifts to 2θ = 12o at 380oC indicating a smaller d-spacing. The Miller indices for this peak are dhkl = 1,1,1. The plane passes at a diagonal through the channels
41 of the framework. This indicates that the shift to smaller d-spacing occurred because the
solvent was removed from the channels of the framework causing the unit cell to shrink
slightly. These results are in agreement with the conclusion that the DMF molecules can
be removed from the channels with retention of the overall framework. The powder
pattern at 900oC was compared to known patterns in the inorganic crystallographic
database and confirmed the decomposition of the framework to LnOSO4 (Ln = La, Gd,
Eu, Y).
3.5. Solid State Photoluminescence
The solid state photoluminescence spectrum of the europium compound 3 was
taken at room temperature and can be seen in Figure 15. When excited at 392 nm,
compound 3 emits a red luminescence (Figure 15c). The emission peaks are attributed to
5 7 the D0- Fn (where n =1, 2, 3, 4) transitions. The peaks appear at 591, 617, 651 and 698
5 7 5 7 nm with the strongest emission attributed to the D0- F2 transition at 617 nm. The D0- F2 electric-dipole transition is sensitive to the coordination environment around the
5 7 europium ion and is almost twice the intensity of the D0- F1 transition (a magnetic dipole
transition relatively insensitive to the coordination environment) which indicates that the
europium ion does not sit on an inversion center. The enhanced luminescence of the
framework 3 is most likely attributed to the rigidity of the framework, which reduces the
loss of non-radiative energy through bonds.125-127
42
5 7 180000 D F 0 2 160000 Intensity (a.u.) 140000
120000 200 250 300 350 400 450 500 wavelength (nm) 5D 7F 100000 0 1 5 7 Intensity D F 80000 0 4
60000 7 5D F 0 3 40000
20000 500 600 700 800 900 W avelength (nm)
(a)
(b) (c)
Figure 15: (a) Excitation (inset) and emission spectra of coordination polymer 3 at excited at 390 nm. (b) Coordination polymer 3 under visible light (c) Coordination polymer 3 under UV light (long wavelength)
3.6. Catalytic Properties
The following section was not published in J. Chem. Cryst. 2010, 40, 222, as the
previous sections were. The heterogeneous catalytic properties of coordination polymer 1
were assessed using an organic reaction known as the Biginelli reaction (Scheme 4).106
43
H O O O O CP 1a R1 N O + + +H2O H N NH Toluene or MeOH O NH R1 H 2 2 O 110oC, 1hr O R1 =aryl
Scheme 4: The Biginelli reaction using CP 1a as a heterogeneous catalyst.
Compound 1, was evacuated in the oven at 250oC for 1 hour to give the activated catalyst
1a and then stored immediately under argon until use. The results of the catalytic
experiments are shown in Table 1. A solid product was isolated after the reaction. The
yield of dihydropyrimidinone product was calculated based on the ratio of product to
starting material. The area under the product peak was compared to the area under the
starting material peak in the GC-MS trace. The control used for this experiment was
Yb(OTf)3, which showed good conversion to the dihydropyrimidinone 10a under reflux conditions (50 %). The proposed mechanism for the Biginelli reaction using a Lewis acid catalyst is shown in Scheme 5. The evacuated catalysts 1a and 2a gave low yields (10-
25 %) of dihydropyrimidinone 10a under reflux conditions in either toluene or methanol.
The activated catalysts showed similar yields for dihydropyrimidinone 10b in either toluene or methanol. It’s interesting to note, there was no catalytic activity when stirred at room temperature for 3 days in reactions involving both 1a and 2a. This could be
attributed to the organic linker being slightly basic, making the lanthanide ion not as
electropositive.
44 Table 1: Catalytic syntheses of dihydropyrimidinones using CP 1a and 2a under different
a reaction conditions.
______b d R1 Solvent Catalyst Product Yield (%) Temperature ______C6H5 toluene none 10a 0 110 C6H5 toluene Yb(OTf)3 10a 49 110 C6H5 none Yb(OTf)3 10a 55 110 C6H5 toluene 1a 10a 21 110 C6H5 MeOH 1a 10a 11 110 C6H5 toluene 2a 10a 21 110 C6H5 MeOH 2a 10a 21 110 C6H5 none 2a 10a 16 110 C6H5 toluene 1a* 10a 0 RT C6H5 MeOH 1a* 10a 0 RT C6H5 toluene 2a* 10a 0 RT C6H5 MeOH 2a* 10a 0 RT ______c 3-thienyl toluene 1a 10b 14 110 c 3-thienyl MeOH 1a 10b 10 110 c 3-thienyl toluene 2a 10b 23 110 c 3-thienyl MeOH 2a 10b 18 110 ______a o For Yb(OTf)3; 1 mL, reflux, 5 hr. For 1-2; 0.2 mL, 110 C, 1 hr. b 5 mol % MOF 1-2; a = framework activated at 250oC. * room temperature, 3 days. c 1.0 mL, 110oC, 1 hr. d temperature in oC.
45 MOF 1a MOF 1a O O -H2O O O H2N NH H2N N O + H R H H N NH R OH R1 H R1 H 1 2 2 1
a F 1 MO O O CH3 EtO
O R O R O R1 1 1 H R1 -H O H+ EtO NH 2 EtO NH EtO NH H N N 2 Ln O O O H3C N H3C O O H3C N HO H H N H 2 10a
Scheme 5: The proposed mechanism for the Biginelli reaction using an activated
coordination polymer as a heterogeneous catalyst.
3.7. Conclusion
Four new lanthanide-thiophenedicarboxylate coordination polymers, 1-4, were
synthesized using both a solvothermal and reflux method. Both methods can be used to
produce the same frameworks as shown by x-ray powder diffraction. Single crystal x-ray
diffraction indicated that metal-carboxylate bonds form slightly different dimers for 1-4,
while the 2,5-TDC acts as the linker to form neutral three dimensional 4,4-nets with diamond shaped channels. Thermogravimetric analysis and IR spectroscopy indicated
o removal of solvents (DMF and H2O) from the channels up to 400 C, above which
decomposition of the framework ensued to give LnOSO4 (Ln = La, Gd, Eu, Y). Powder
diffraction data indicated that the 3D structure remained intact with a small contraction in
at least one cell parameter. The catalytic activity of 1a and 2a was assessed in the
Biginelli reaction. The homogeneous control catalyst, Yb(OTf)3, showed the best
46 catalytic activity. There was limited activity for the activated catalysts 1a and 2a (10-
25 %) at reflux temperature in either MeOH or toluene. The catalysts showed no activity
when stirred at room temperature for 3 days. Catalysis was found to be occurring on the
surface of the coordination polymers which is in accord with the inability of the product
to fit in the channels of the framework.
Due to the success in forming coordination polymers 1-4 using the solvothermal
and reflux methods, the same methods were considered for the synthesis of
tetrafluorobenzene-1,4-dicarboxylic acid/lanthanide-based MOFs. The need for a more
acidic linker like tetrafluorobenzene-1,4-dicarboxylic acid, as opposed to 2,5-TDC, was
imperative. These fluorine atoms should increase the electron-withdrawing power of the
linker and make the lanthanide centers more electropositive, which will make them better
Lewis acids and help increase the catalytic activity of the ensuing frameworks.
Utilization of the solvothermal method, which was employed for the synthesis of
coordination polymers 1-4, gave no product in the case of coordination polymers 5-9.
Once the temperature was increased from 105oC to 145oC and the heating was extended
from 24 to 48 hr, a crystalline product was obtained. We concluded, based on the single
crystal x-ray diffraction data, that the single crystals were of the starting material
Tb(NO3)3. In order to synthesize coordination polymers 5-9 with tetrafluorobenzene-1,4-
dicarboxylic acid, a different tactic was employed which is discussed in the next section.
47 CHAPTER 4
SYNTHESIS, CRYSTAL STRUCTURE AND PROPERTIES
OF COORDINATION POLYMERS 5-9
Christopher M. MacNeill, Cynthia S. Day, Amy Marts, Abdessadek Lachgar and Ronald
E. Noftle
The following chapter was published as a manuscript in the journal Inorganica Chimica
Acta, 2011, volume 365, pages 196-203, and is reprinted with permission from the journal. All of the research presented was conducted by Christopher M. MacNeill with help from Amy Marts. Crystal Structure Data was compiled by Cynthia S. Day. The manuscript was prepared by Christopher M. MacNeill and edited by Abdessadek Lachgar and Ronald E. Noftle
48 4.1. Synthesis of Coordination Polymers 5-9
Initially, a solvothermal method was employed at varying temperatures (100, 120
and 145oC) from 18-48 hours in an array of different solvent systems without adjustment
of pH; however, crystals suitable for single-crystal X-ray diffraction were not obtained.
The synthesis of coordination polymers 5-9 was carried out by a vapor diffusion method which resulted in precipitation of high purity samples. Stoichiometric ratios of 1:1 lanthanide metal to H2F4BDC were utilized for all syntheses, and, in all cases, the same
framework resulted, as indicated by single crystal and powder x-ray diffraction. N,N-
Diethylformamide (DEF) was the preferred solvent since use of DMF resulted in
microcrystalline products. Ethanol was chosen as a co-solvent because enhanced crystal
growth resulted compared to use of DEF/H2O, DEF/MeOH, and DEF/n-propanol
mixtures. The bound solvent cannot be removed at RT, but the compounds tend to lose
lattice DEF upon exposure to air and under vacuum. This is reflected in the analytical
results which show varying amounts of remaining DEF in the lattice.
Five new isostructural two-dimensional lanthanide-based coordination polymers
with the formula Ln2(F4BDC)3(DEF)2(EtOH)2 · 2(DEF) (Ln = Tb, 5; Gd, 6; Eu, 7; La, 8;
2- Nd, 9; F4BDC = 2,3,5,6-tetrafluoro-1,4-benzenedicarboxylate ligands; DEF = N,N’- diethylformamide), have been synthesized by reaction of Ln(NO3)3 and H2F4BDC in a
DEF/EtOH solvent mixture. The compounds were characterized by single-crystal and
powder X-ray diffraction. Compounds 5-9 were further characterized using thermo-
gravimetric analysis and infrared spectroscopy. Studies of the photoluminescence
properties of compounds 5 and 7, as well as the catalytic activity of compounds 7-9 in the
Biginelli reaction, are presented.
49 4.2. Single Crystal X-Ray Diffraction
4.2.1. Crystal Structure of Tb2(F4BDC)3(DEF)2EtOH2 · 2(DEF) (5)
Coordination polymer 5 crystallizes in the monoclinic space group C2/c. The
carboxylic acid moieties are completely deprotonated and the framework forms an
overall 2D structure. The asymmetric unit contains one terbium ion, one and a half
2- F4BDC molecules, one terminal DEF molecule, one EtOH molecule and one lattice
DEF molecule (Figure 16a). There are two asymmetric units contained in each formula
2- unit. Each terbium ion is 9-coordinate with two bridging F4BDC oxygen atoms (O(1)
2- 2- and O(2)), two bidentate F4BDC molecules (O(3), O(4)), one μ3-F4BDC molecule
(O(5), O(6)), one oxygen (O(7)) from the terminal DEF molecule and one oxygen (O(8))
from the terminal EtOH molecule. The lattice DEF oxygen (O(9)) is hydrogen bonded to
2 the hydrogen on the sp carbon on the coordinated ethanol molecule. The TbO9 polyhedra
can be described as tri-capped trigonal prisms. The terbium atoms are linked through the
2- 2- oxygen atoms from two bridging F4BDC ligands (O(1), O(2)), and two μ3-F4BDC ligands (O(5), O(6)) to form a dimer (Figure 16b and 16c).
The Tb(1)-Tb(1) distance is 4.1450(4) Å. All of the Tb-O distances from the
2- F4BDC range from 2.319(2) Å to 2.478(2) Å, which corresponds well to known terbium-oxygen bond distances.128-129 The hydrogen bond distance from the lattice DEF
molecule to the ethanol molecule is 1.87(5) Å.
50
a) b)
c)
Figure 16: a) A view of the contents of the asymmetric unit for
Tb2(F4BDC)3(DEF)2(EtOH)2 · 2(DEF) (5). Hydrogen atoms have been omitted for
clarity. (b) A view of the formula unit of 5 with two identical terbium atoms. (c) A view
of the formula unit of 5, where the contents of the polyhedra represent the terbium atoms.
2- The dimers are further bridged through six F4BDC linkers (Figure 17a) to other dimers
to form an infinite two-dimensional sheet along the bc-plane (Figure 17b). The sizes of
the rhombic channels are 11.5 X 11.5 Å based on the distance between terbium atoms.
Each two-dimensional sheet is stacked to form a 3D layered topology along the a-axis
51 (Figure 18a-b). The DEF and ethanol molecules are trapped in the layers between the 2D
sheets, which have a size of 12.9 Å (Ln-Ln distance).
11.5 Å
11.5 Å a) b)
2- Figure 17: a) A view of the dimer of 5 connected to other dimers through six F4BDC linkages. (b) A view of (a) forming an overall 2D sheet with solvent molecules and hydrogen atoms omitted for clarity.
12.9 Å a) b)
Figure 18: (a) A view of the 2D sheet of coordination polymer 5 along the b-axis. (b) formation of a 3D layered topology from stacking of the infinite 2D sheets from (a). lattice DEFs were omitted for clarity.
52
4.2.2. Crystal Structures of Gd2(F4BDC)3(DEF)2EtOH2 ·2(DEF) (6), Eu2(F4BDC)3-
(DEF)2EtOH2 · 2(DEF) (7), La2(F4BDC)3(DEF)2EtOH2 · 2(DEF) (8) and
Nd2(F4BDC)3-(DEF)2EtOH2 · 2(DEF) (9)
Coordination polymers 6-9 crystallize in the same space group as coordination polymer 5, monoclinic C2/c. The carboxylic acid moieties are completely deprotonated and the frameworks form an overall 2D structure that is isostructural with framework 5.
The x-ray powder diffraction data comparing the simulated pattern to the as-synthesized patterns for these frameworks can be seen in Appendix B8.
4.3. Thermogravimetric Analysis
The thermal stability of compounds 5-9 was investigated using thermogravimetric analysis by heating the samples in air to 900oC at a heating rate of 5oC/min (Figure 19).
In the case of compound 5, there was a loss of two coordinated EtOH molecules between
40-115oC, followed by loss of two lattice DEF molecules from 115-200oC (calc. 19.3 %
exp. 19.2 %). A final weight loss of two coordinated DEF molecules occurred between
250-325oC (calc. 13.2 % exp. 13.0 %). The compound is stable to 250oC and begins to decompose at 325oC to give terbium oxyfluoride (TbOF) at 900oC as determined by
PXRD.116 Similar solvent losses were observed for compounds 6-9.
53
120 5 100 6 7 8 80 9
60
Weight % 40
20
0 0 100 200 300 400 500 600 700 800 900 1000 o Temperature ( C)
Figure 19: The TGA curves of coordination polymers 5-9.
4.4. Infrared Spectroscopy:
The infrared spectra of 5-9 were measured between 400 and 4000 cm-1 (Appendix
B7). The IR spectrum of 7 shows a broad band at 3450 cm-1 which corresponds to the O-
H stretch of the ethanol. The weak vibrations at 2989 cm-1 and 2950 cm-1 correspond to
the DEF C-H methyl and DEF C-H aldehyde stretching modes. The stretching frequency
for the carbonyl group on the benzene ring, normally in the range of 1680-1720 cm-1, was
lowered after coordination to the lanthanide metal ion. The asymmetric and symmetric
stretching modes for the bound carboxylate groups occur at 1623 cm-1 and 1411 cm-1.
The DEF C=O stretch can be seen at 1660 cm-1. After heating to remove solvent from the
lattice, the IR spectrum of compound (7a) was taken. The spectrum shows that the DEF
C-H aldehyde and DEF C-H methyl stretches are no longer apparent, which indicates that
54 the DEF can be removed from the lattice and activated before its use in the catalytic
experiments (Figure 20).
(7)
Transm ittance
(7a)
no DEF C-H methyl or DEF C-H aldehyde stretch in 7a.
4000 3500 3000 2500 2000 1500 1000 500 0 wavenumber (cm-1)
Figure 20: The infrared spectra of coordination polymer 7 (as synthesized) and
coordination polymer 7a (after evacuation to remove solvent from the lattice).
4.5. Solid State Photoluminescence:
The room temperature solid state photoluminescence spectra for 5 and 7 were
taken and can be seen in Figure 21. Upon excitation, 5 emits a green luminescence. The
5 7 transitions appear at 489, 544, 585 and 620 nm and are attributed to the D4- Fj (J =
130-132 5 7 6,5,4,3) bands. The D4- F5 transition (hypersensitive) is the most intense peak and
5 7 133 the D4- F6 transition is second in intensity consistent with other Tb-based systems.
Compound (7) emits a red luminescence. The emission peaks which appear at 590, 615,
55 5 7 650 and 695 nm are attributed to the D0- Fj , (J = 1,2,3,4) transitions respectively, with
5 7 the strongest emission attributed to the D0- F2 transition at 615 nm.
a) b)
Tb2(F4BDC)3(DEF)2(EtOH)2-2(DEF) (1) Eu2(F4BDC)3(DEF)2(EtOH)2-2(DEF) (3)
5D 7F 0 2 5 7 D0 F1 5 7 D4 F5
5 7 D4 F6 5 7 D0 F4 Relative Intensity (a.u.) 5 7
D4 F4 Relative Intensity(a.u.) 5D 7F 5 7 4 3 D0 F3
350 400 450 500 550 600 650 450 500 550 600 650 700 750 Wavelength (nm) Wavelength (nm)
c) d)
Figure 21: (a) A picture of Tb 5, Eu 7 and La 8 coordination polymers under visible light.
(b) A picture of Tb 5, Eu 7 and La 8 coordination polymers under UV light. (c) The solid
state photoluminescence spectrum of Eu 7 excited at 392 nm. (d) The solid state photoluminescence spectrum of Tb 5 excited at 300 nm.
56 5 7 The appearance of the broad, low intensity, forbidden D0- F0 transition indicates that the
5 7 metal is in a non-centrosymmetric ligand field. The D0- F2 electric-dipole transition is
sensitive to the coordination environment around the europium ion and is almost twice
5 7 the intensity of the D0- F1 transition (a magnetic dipole transition relatively insensitive to
the coordination environment) which again indicates that the europium ion does not sit on
an inversion center. This information was helpful in the crystal structure analysis.134-136
4.6. Catalytic Properties:
Lanthanide triflate salts are the most widely used homogeneous Lewis acid
catalyst in the Biginelli reaction, giving yields of >80 % in a number of solvents, under a
range of conditions, and using a variety of different starting reagents.137 Lanthanide
triflates, however, are difficult to recover because excess solvent must be removed and
the triflates must be dried under vacuum for several hours. The Biginelli reaction has
been used to assess the Lewis acid catalytic properties of HIOMs by other groups.138-140
However; their syntheses were carried out at room temperature and take 2-3 days. In light of this fact, we explored the catalytic activity of the compounds reported here under a shorter time period (1.5 hr) and a longer period (3 days) under different conditions of temperature. Compounds 7-9 all gave similar yields so we chose to focus on compound 7 for our study.
The catalytic activity of 7 and its activated catalyst 7a, from which solvent had been removed, were compared and the results are presented in Table 2. Compound 7 is interesting in that it is insoluble in everything except water, so its homogeneous catalytic activity in water as well as its heterogeneous activity in toluene and methanol was
57 investigated. The europium catalyst gave greater than 50 % of the yield observed for
o Yb(OTf)3 but at a lower temperature (70 C) in about 30 % of the time. In the case of heterogeneous reactions, the catalyst was easily recovered and re-used without loss of activity (Appendix B9-B10).
Table 2: Catalytic syntheses of dihydropyrimidinones using CP 7, 7a, 8 and 9 under
a different reaction conditions. ______b d R1 Solvent Catalyst Product Yield (%) Temperature ______C6H5 toluene none 10a 0 110 C6H5 toluene Yb(OTf)3 10a 49 110 C6H5 none Yb(OTf)3 10a 55 110 C6H5 toluene 7 10a 28 70 C6H5 MeOH 7 10a 33 70 C6H5 toluene 7a 10a 38 70 C6H5 MeOH 7a 10a 39 70 C6H5 toluene 7* 10a 10 RT C6H5 MeOH 7* 10a 21 RT C6H5 H2O 7* 10a 41 RT C6H5 toluene 7a* 10a 12 RT C6H5 MeOH 7a* 10a 19 RT C6H5 H2O 7a* 10a 37 RT ______c 3-thienyl toluene 7 10b 13 70 c 1-napthyl toluene 7 10c 12 70 c 3-thienyl toluene 7a 10b 16 70 c 1-napthyl toluene 7a 10c 9 70 ______C6H5 toluene 8 10a 28 70 C6H5 toluene 9 10a 27 70 ______a o For Yb(OTf)3; 1 mL, reflux, 5 hr. For 7-9; 0.2 mL, 70 C, 1.5 hr. b 5 mol % MOF 7-9; a = framework activated at 150oC. * room temperature, 3 days. c 1.0 mL, 70oC, 1.5 hr. d temperature in oC.
58 At room temperature over three days, reactions in water give higher yields of
dihydropyrimidinone, comparable to those of Yb(OTf)3, as would be expected for
homogeneous catalysis. To determine whether catalysis was occurring in the layers or on the surface of the framework, we compared the catalytic activity of the activated catalyst
7a to 7.
The activated catalyst gave somewhat higher yields at 70oC than did the
unactivated catalyst. This may be due to the greater availability of the Lewis acid sites on the lanthanide metal because of the removal of coordinated solvent molecules from the
framework. There was no significant difference at room temperature. Aldehyde reactants
of different sizes (3-thiophenecarboxaldehyde, 5.7 Å; benzaldehyde 6.1 Å; 1-
napthylcarboxaldehyde, 7.9 Å)141 were chosen to see if catalytic activity decreased as the size of the reactant increased. The distance between the layers in (7) is 7.4 Å (based on
Eu(1)-Eu(1) distance). The yields of the corresponding dihydropyrimidinones at 70oC
were similar for the different aldehydes (10b, 13 %; 10c, 12 %) indicating a constant
activity, regardless of size. These results suggest that catalysis occurs at the surface and
not between the layers. Finally, the catalyst was finely ground to increase surface area. If
catalysis were taking place on the surface, as the surface area increased, the yield of the
Biginelli product should also have increased. A modest increase in Biginelli product was
observed (7-10 %) consistent with the conclusion that catalysis occurs on the surface.
Compounds 8 and 9 gave yields comparable to those obtained for 7 at 70oC for 1.5 hr.
4.7. Conclusion
Five new 2D lanthanide-based coordination polymers incorporating 2,3,5,6-
tetrafluoro-1,4-benzenedicarboxylate have been synthesized using a vapor diffusion
59 method and characterized by single crystal x-ray diffraction, powder diffraction, infrared spectroscopy and thermogravimetric analysis. The framework consists of lanthanide
2- metal ions linked by [F4BDC] ligands to form 2D sheets, which stack to form a layered
topology with solvent molecules between the sheets. DEF and EtOH can be removed
from the layers with full retention of the framework upon heating to 150oC. Compounds
5 and 7 showed photoluminescent properties upon excitation at 392 nm and 350 nm, respectively. Compounds 7-9 showed catalytic activity in the Biginelli reaction. The increase in temperature from RT to 70oC provided a more rapid synthesis (1.5 hr vs. 3
days) compared to previous methods.142-143 Evidence suggests that the catalysis is taking
place at the surface of the framework and not within the layers of the framework.
60 CHAPTER 5: INTRODUCTION
5.1 The Environment
At the rate of present consumption of fossil fuels and the strain it puts on the
environment, it is only a matter of time before we have to rely on other energy sources.144
Currently, 80% of energy comes from fossil fuels such as coal, oil and gas.145 Fossil fuels
are of limited supply and the price of oil is increasing rapidly, so the need to move to an
alternative energy source is looming. Solar energy is of unlimited supply and is a clean
and renewable energy source. We receive 3.9×1024 J of energy from the sun annually. In
2004, the world energy consumption was 4.7×1020 J. This means in one hour, we can
supply the entire world with enough energy to fulfill our yearly demand.146-147Grid-
connected organic photovoltaic modules can now be installed on the roofs of houses and the windows of buildings. However, the cost of such undertakings is still too high. For
the past thirty years, the cost of organic-based photovoltaics has continuously
decreased.148 Currently, depending on country and availability, the price of small cell
organic solar modules is anywhere between 8-12 US$/W with efficiencies between 1-3%
and lifetimes under 2 years. The future cost of organic solar cells should decrease, while
improvements in solar cell lifetime and efficiency should increase. By 2025, solar cell
lifetimes should improve to 5-7 years, with efficiencies between 5-9 % at a cost of 0.5
US$/W. 149
61 5.2 History of Photovoltaics
5.2.1 Photoelectric effect
Before introducing the history of inorganic and organic photovoltaic cells, a brief
history of the photoelectric effect will be introduced. The definition of the photoelectric
effect is when a material absorbs light of short wavelength, such as visible or ultra-violet,
and electrons are emitted from the material.150 Hertz coined this term in the late 1880’s
when he discovered the phenomenon.150-151 The understanding of the photoelectric effect opened the door to an understanding of how electrons move under electromagnetic radiation. Albert Einstein demonstrated a mathematical relationship between energy and frequency when he described light as photons and not as waves.152-153 He theorized that if a photon has energy above the threshold frequency, then a single electron can be ejected
(E = hυ). He later won the Nobel prize in physics in 1921 for this work.
The photovoltaic (PV) effect was first observed by Alexandre Becquerel in 1839.
He showed a relationship between light and the electronic properties of materials, while illuminating an aqueous solution containing two platinum electrodes covered in silver bromide and silver chloride.154 It wasn’t until 30 years later between 1873 and 1876, that
Willoughby Smith along with William Adams, discovered that selenium can be
photoconductive.155-156 Up to the 1940s, research on new photoconducting materials,
based on selenium, copper, thalium and lead, was underway.157-162
5.2.2 Inorganic Photovoltaics
The first thin film solar cell based on elemental selenium was realized in the
1880’s by the work of Fritts.163 He coated a selenium semiconductor with gold and
62 achieved an efficiency of 1%. Russell Ohl holds the first solar cell patent (US Patent
2402662) and in 1939, discovered the p-n junction by investigating impurities in
crystals.164 It was not until the 1950s that commercialization of inorganic solar cells was
initiated. Bell laboratories produced the first inorganic solar cell made of crystalline
silicon and it had a power conversion efficiency (PCE) of 6%.165 Since then, crystalline
silicon-based solar cells have dominated the photovoltaic market, reaching efficiencies of
24 %, near their theoretical upper limit of 30 %.166-170 Silicon-based cells are known as
“first generation” solar cells. Silicon is abundant, making up 20 % of the earth’s crust and
solar cells constructed from silicon can typically last 25-30 years, when fabricated into a
device. However, these cells require a large area, and are very labor-intensive to
produce.171 Currently, some first generation solar cells have been replaced by a “second generation” technology based on thin film/semi-conductors. These materials include cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous silicon.172 Second generation photovoltaic efficiencies range from 5-20 %. The best
known efficiency of an amorphous silicon based cell is 9.4 % with a cost of 1-2 US$/W.
For CdTe and CIGS, PCEs of 16.7 % and 19.4 % have been realized with a cost of 2 -2.5
and 1 US$/W.173-174 For the past fifteen years, a trend to move from “second generation”
thin film/semiconductors to “third generation” organic-based solar cells is proceeding.
This is due to the need for a technology that is low cost, flexible, easily manufactured and
very efficient. Since second generation solar cells can now be made on a large scale and
cost has decreased to around 1 US$/W, this makes the potential for cost reduction of
organic solar cells a future reality.
63 5.2.3 Organic Photovoltaics
The first organic molecule to show photoconductivity was anthracene in the early
1900’s.175-176 Interest in organic molecules was growing during this time period, which led to research on organic molecules as potential photoconductors. Common dyes, such as methylene blue and biological molecules, such as chlorophyll and porphyrins, were found to exhibit the PV effect during the 1950s-1960s.177-178 Polymeric materials were
first thought to be insulating; however, it was found that they can exhibit semi-
conducting or even metallic properties.
Conjugated polymers are materials that are completely sp2 hybridized. Because of
this, the p-orbitals overlap and an electron can be delocalized along the chain. This
overlap and delocalization allows for charge to be shuttled along the backbone leading to
interesting electrical and optical properties. One of the first reports of a conducting
polymer was poly(vinyl carbazole).179 This was later followed up by the pioneering work
of Heeger on poly(acetylene) films.180-181 Their group found that if you doped
poly(acetylene) with iodine, the conductivity increased 108 fold. The first solar cell
device made with poly(acetylene) came from Weinberger and co-workers.;182 however, the cell had a very low Voc (0.3 V). During the early 1980’s, polythiophenes were
183 investigated for their PV applications. The limitation again was the Voc and the quantum efficiency. Finally in the early 1990’s, poly(phenylene-vinylene) cells showed a
184 high Voc (1 V) and a PCE of 0.1 %. The first report of a solar cell using a conjugated
polymer as a donor and a fullerene acceptor was reported by Heeger and co-workers in
the mid 1990’s.185-187 The cell was based on poly(2-methoxy-5-(2’-ethyl-hexyloxy)-p-
phenylene-vinylene) (MEH-PPV). However, this polymer was not easily processable and
64 the band-gap was too large. Power conversion efficiencies (PCE) for MEH-PPV/C60 systems could only reach PCEs of 3 % overall. It was not until 2002, that poly(3-
188 hexylthiophene) (P3HT) polymers with C60 gave the most encouraging results. Since then, the potential for polymer-based photovoltaics has increased substantially with some polymer/fullerene composites reaching a PCE of close to 5 %.189-190 However, a PCE of
5% still is not good enough to compete with silicon technologies. Development of new p-
type conjugated polymers that can reach 10 % efficiency191-192 are needed and the
synthesis of these polymers will play a pivotal role in driving the future of this field.
Insight into new donor-acceptor copolymers for organic solar cell applications will be
discussed in Chapters 7-9 of this text.
5.3 Theory and Device Physics of Organic Solar Cells
The fundamental steps of polymer solar cell operation193 are as follows (Figure
22). 1.) light passes through the ITO substrate and is absorbed by the donor polymer. 2.) an electron is promoted from its highest occupied molecular orbital (HOMO) to its lowest unoccupied molecular orbital (LUMO). This forms a coulombically bound electron/hole pair, also known as an exciton. This exciton then travels along the polymer backbone diffusing towards the donor/acceptor interface where there is a drop in potential energy.
Ideally, this distance would be around 5-20 nm for most semi-conductors.194-196 3.) the electron is transferred from the LUMO of the donor polymer to the LUMO of the acceptor material. 4.) each charged species now has to diffuse through the device towards their respective electrodes. The hole travels towards the anode while the electron travels towards the cathode. Once the charge reaches the contacts, the photon to electron process
65
Figure 22: A schematic representation of the steps involved in generating photocurrent in
a donor-acceptor polymer solar cell device.
is complete. In some cases, once the exciton is produced, the charges may re-combine
and give off a photon. At this point, the ability to generate a photocurrent will cease. A donor polymer with low ionization energy and an acceptor with a high electron affinity would be ideal for organic photovoltaic applications. Here are a few terms one may come across when accessing a polymer-based solar cell material.
5.3.1. Open Circuit Voltage (Voc)
The open circuit voltage of a device is defined as the difference in electrical
potential between the anode and the cathode when there is no external connection, i.e. the
circuit is open. It is known as the maximum voltage for a solar cell and occurs when no
current is flowing. The Voc can also be considered as the difference in work functions
between the two metal contacts in the cell.197 If there is not a good overlap of the orbitals
on the metal with the orbitals of the polymer, there can be charge carrier loss and the Voc
66 will decrease. Theoretically, the Voc can be estimated by the difference in voltage between the HOMO of the donor material and the LUMO of the acceptor material in
198-199 volts. The Voc of a material tends to increase with increasing band-gap according to
200 an equation outlined by Baruch and co-workers. Vocs of 0.7 V or higher are ideal for
solar cell applications.
T s V oc = Eg 1- T c(0)
Equation 1: An equation relating the band gap (Eg) of a polymer to the open circuit
200 voltage (Voc) by Baruch and co-workers.
5.3.2. Short Circuit Current Density (Jsc)
The short circuit current density is the maximum current of a solar cell in which
the impedance is low and the voltage is zero. The short circuit current depends on many
factors associated with the solar cell such as the optical properties of the materials, the
charge carrier lifetime, and the area of the cell.
5.3.3. Fill Factor (FF)
The FF is defined as the ratio of the maximum power of the solar cell to the
theoretical obtainable power of the cell. The FF can also be defined as the ratio of the
number of charge carriers reaching the electrodes compared to those recombining,
expressed as a percentage. When an exciton is generated, it has to migrate to the acceptor
molecule and transfer its charge. Once the charge is transferred, the electron hops
towards the cathode, while the hole moves towards the anode. The exciton diffusion
67 length can play an important role in obtaining a large FF. If the diffusion path of the exciton is too long (>10 nm), the charges will recombine and the FF will be dramatically decreased. Generally, a FF of at least 65 % is required for the cell to potentially achieve
10 % PCE.198 The fill factor can be improved by adding an electron transport layer to the
electrode such as lithium fluoride (LiF)201-203 or a hole transport layer such as
polyethylenedioxythiophene: polystyrenesulfonate (PEDOT:PSS).204 By using a bulk
heterojunction device, where donor and acceptor are blended together, the diffusion of
the exciton will be less than 10 nm and an optimum fill factor will be obtained. The FF
tells how well the solar cell is working. Typically, FFs for a good organic photovoltaic cell are between 0.5-0.7. A graph of the J-V curve of a solar cell under solar illumination is seen in Figure 23.
Figure 23: A J-V curve (black) of a BHJ solar cell under illumination. Characteristic open circuit voltage (Voc), short circuit current (Jsc) and FF (Area A/Area B), as well as
the calculation of power conversion efficiency (PCE) are indicated on the figure.
68 5.4 Device Architectures of Organic Solar Cells
There are three types of polymer-based solar cell devices; the bi-layer device, the
bulk-heterojunction (BHJ) device and the tandem solar cell device (Figure 24). A bi-layer
device is comprised of a hole-type donor material lying on top of an electron acceptor
material.205-207 The limitation of this device architecture is that the sizes of hole donor material and the electron acceptor material are generally greater than the exciton diffusion length (5-12 nm)208 of the generated hole/pair. If the exciton is not successfully
transferred to the acceptor material, the exciton recombines and the photocurrent is lost.
(a) (b) (c)
Figure 24: A representation of (a) a bi-layer solar cell device, (b) a BHJ solar cell device
and (c) a tandem solar cell device
A BHJ device is different from a bi-layer device in that the donor and acceptor materials
are blended together in a single layer. This gives greater external quantum efficiency to a
BHJ device compared to bi-layer device due to the presence of a single active layer as
opposed to a bi-layer where the interface between the layers is known to erode with
time.209 This architecture also helps prevent recombination of the exciton because the
acceptor material is now within the exciton diffusion length. A tandem solar cell consists
of a blend of two or more polymers separated by a thin charge carrier layer and connected
69 in series.210 One sub-shell (bottom device) can be made up of a certain polymer blend that
absorbs in the blue region of the visible spectrum, while the second sub-shell (top device)
can be made up a blend that absorbs in the red region of the spectrum. Together, these two sub-shells connected make up a cell that absorbs over most of the visible region making use of more sunlight then just a discrete single cell.210 The first tandem solar cell
was made up of small organic molecules,211 but, since then, research has expanded to
212 solution-processed bulk heterojunction cells with blends of MDMO-PPV:PC60BM and
213 P3HT/PCBM: ZnPc/C60. The largest PCE of any bulk heterojunction tandem solar cell
was reported by Kim and co-workers.214 The cell is entirely solution processed with the
top cell comprised of a P3HT:PC70BM:PEDOT/PSS blend while the bottom cell was a
PCPDTBT: PCBM:PEDOT/PSS blend. The cells were separated by a titanium dioxide
layer. This cell had a 38% performance increase and a PCE of an unprecedented 6.5%.
5.5 Critical Parameters for Organic Solar Cells
Many different electron-acceptors have been employed in BHJ devices. The most
widely used acceptor to date is Buckminsterfullerene C60, which can accommodate up to
six electrons in a reductive process. Due to its limited solubility, other more soluble C60 derivatives such as 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (PCBM) have been
215 utilized in devices. Derivatives of C60 make great electron acceptors in BHJ devices
because of their low lying LUMO, which makes the transfer of an electron from the p-
type material thermodynamically favorable.216 Also, electron transfer from the donor
materials to the C60 derivatives takes place in close to 45 femtoseconds, which is faster than the donor electrons decay back to their ground state.217
70 For n-type materials, C60 derivatives are the frontrunner; however, synthesis of
new hole-type donor materials is imperative. To date, these p-type donor materials are
mostly based on conjugated polymers.
Excitement has been building in academic and commercial laboratories due to the possibility of producing large scale BHJ solar cells that can be easily processed at low cost with good efficiency. However, optimization of these devices is still needed in order to compete with silicon technologies. There are some considerations needed when determining how to build the ideal polymer solar cell device: 1.) the band-gap of the polymer. 2.) the LUMO of the donor. 3.) the minimum offset of LUMOs between donor and acceptor. 4.) the fill factor and open circuit voltage. 5.) how the device is assembled.
The band-gap of a polymer is the difference in energy (ΔeV) between the HOMO and the LUMO. These can range from 1.5 eV (semi-conductor) to 3 eV (insulator) based on the monomers chosen. A band-gap of 1.1 ev (1100 nm) can absorb about 77 % of all solar energy photons;218-219 however, most donor polymers have band-gaps around 2 eV
(620 nm), which greatly limits these donor polymers as potential materials in
photovoltaic devices.198 Researchers are in need of new low band-gap polymers in order
to harvest solar energy reaching the earth more efficiently.
The LUMO of the donor polymer is also very important. The ideal LUMO energy
level for a donor is -3.9 eV, which can give PCEs of close to the theoretical limit of 10 %
if the polymer has a low band-gap.220-221 The minimum offset in LUMO’s between the
donor polymer and the PCBM acceptor is essential to facilitate electron transfer in order to obtain charge separation and, in turn, a photo-current.222-223 If the LUMO energy level
of the donor is ideally around -3.9 eV, the LUMO energy level of the acceptor should be
71 a minimum of 0.3 eV lower. The LUMO energy level of PCBM is -4.2 eV, which makes
this material an ideal acceptor.
Finally, understanding how to tailor the intrinsic properties of the polymer can be
imperative to achieve high efficiencies. In order to investigate the nanomorphology of the
polymer, electron microscopy is used. Nanoscale phase separation can be seen in some
polymer solar cell devices, which can be detrimental to the device, owing to insufficient
mixing of the donor and acceptor materials. Solvents can also influence the
nanomorphology and degree of phase separation in a polymer film. Shaheen and co-
workers224 found that if an MDMO-PPV/PCBM film is spin-coated from toluene, a PCE of 0.9 % can be achieved. When the solvent is changed to chlorobenzene, an increase in
PCE to 2.7 % is seen. This is attributed to chlorobenzene being a better solvent than
toluene. The blending of the polymer and fullerene in the film is improved in
chlorobenzene, while the polymer and fullerene tend to phase separate into large domains
in toluene, which is harmful to the device efficiencies due to the greater probability of the
exciton recombining in the larger domains. The increased PCE may also be attributed to
the slower drying time of the chlorobenzene film compared to toluene film, which will
give a more crystalline phase within the photoactive layer. The ratio of polymer to
fullerene can affect the morphology and efficiency of the solar cell device. One of the
components may overwhelm the other within the film, inducing segregation of the
materials.
Thermal annealing has also been shown to increase PCEs in P3HT/PCBM based
solar cell devices.225-226 By heat treatment of the device above the glass transition temperature of the polymer, the film can reorganize and give a more crystalline phase.
72 This makes a P3HT device increase from 2.9 % (unannealed) to almost 6 %
(annealed).227 Understanding how to tailor the intrinsic properties of the polymer, as well as fabricating the device properly, will allow one to reach PCEs of up to 10 % for polymer-based solar cell devices and jumpstart polymer solar cell production to become competitive with silicon devices.
5.6 Research Goal
The goal of this research project is to synthesize and characterize new low band
gap polymers for organic photovoltaic applications. The literature consists of hundreds of
polymers that have been fabricated into solar cell devices and tested under solar radiation.
The problem with the majority of these devices is they achieve low efficiencies (< 2 %)
due to either their low molecular weight or their insolubility and, subsequently, poor
processability. Linear alkoxybenzodithiophene/2,1,3-benzothiadiazole (BDT/BT)-based
donor-acceptor copolymers give good open circuit voltages; however, they have poor
current production, molecular weight and power conversion efficiency due to the
insolubility of the linear side chain. The goal of this research project is to synthesize and
characterize new low band gap copolymers based on BDT that are of high molecular
weight and can be solution processed. This will be accomplished by attaching a branched
2-ethylhexyl side chain to the 4- and 8- positions of the BDT unit. Branched side chains
tend to frustrate aggregation, allowing for the polymer to remain soluble in the reaction
solution in order for it to grow and achieve high molecular weights. These copolymers,
incorporating branched side chains, will allow us to obtain a chloroform-soluble fraction
with a high average molecular weight. Other highly branched systems, such as 3-octyl
73 and 6-undecyl, will be attached to the 4- and 8- positions of the BDT unit in order to achieve good solubility and high molecular weight. The band gap, HOMO and LUMO energy levels of the copolymer can be tuned by changing the electron-donating or withdrawing comonomers from BDT and BT to other donors and acceptors based on cyclopentadithiophene (CPDT) and 2,1,3-benzoselenadiazole (BSe), 1,2,5- selenadiazolo[3,4-c]pyridine (PSe), 1,2,5-thiadiazolo [3,4-c]pyridine (PT) and 2,1,3- benzoxadiazole (BO). The synthesis will be carried out in order to decrease the band gap and increase absorption and current production in the devices. Once synthesized, the polymers will be fabricated into bulk heterojunction (BHJ) solar cells and tested under
AM 1.5 g solar radiation.
74 CHAPTER 6: EXPERIMENTAL
6.1. Materials
Diethylamine, thionyl chloride, n-butyllithium (1.6M in hexanes), trimethyltin chloride, 2-ethylhexyl bromide, undecan-6-ol, methanesulfonyl chloride, benzofurazan and 3-octanol were obtained from Sigma-Aldrich Chemical Co (Milwaukee, WI). 3-
Thiophenecarboxylic acid and 3,4-thiophenedicarboxylic acid were obtained from Matrix
Scientific Co (Columbia, SC). Palladium tetrakistriphenylphosphine was obtained from
Acros Chemical Co (Pittsburgh, PA). 1-bromododecane and tetrabutylammonium bromide were purchased from Eastman Chemical Co (Rochester, NY). Bromine, zinc dust, toluene and methanol were purchased from Fisher Chemical Co (Milwaukee, WI).
4H-Cyclopenta-[1,2-b:5,4-b’]dithiophene was purchased from Astar Pharma (Allison
Park, PA). 2,1,3-Benzoxadiazole was purchased from Maybridge Chemical Co (Cornwall,
England, UK). Glassy carbon (d = 1.5 mm or 2 mm) mini-electrodes were purchased from Cypress Systems (Fresno, CA).
6.2. Methods
6.2.1. Analytical Methods
1H and 13C-NMR spectra were recorded on a Bruker Avance DPX-300 NMR sprectrometer. 119Sn NMR spectra were recorded on a Bruker Avance DRX-500 NMR spectrometer. UV-visible absorption spectra were recorded on an Agilent 8453 diode- array spectrophotometer operating over a range of 190-1100 nm. Flash chromatography was performed on a Biotage IsoleraTM Flash Purification System using Biotage SNAP
75 Flash Purification Cartridges as the stationary phase. DSC was performed at 20oC/min from 0oC to 250oC under nitrogen gas (50 mL/min) using a TA Instruments DSC Q200.
Microwave-assisted polymerizations were carried out using a CEM Discover Microwave
reactor. Gel permeation chromatography (135°C in 1,2,4-trichlorobenzene) was
performed by American Polymer Standards (Ohio).
6.2.2. Electrochemical Methods
Electrochemical measurements were carried out using a computer-controlled Pine
Model AFCBP 1 Bi-Potentiostat with PineChem software in a standard single- compartment, three electrode cell. The working electrode was glassy carbon; the counter
electrode was a Pt flag. A silver wire was used as a pseudo-reference electrode and was
periodically calibrated against the Fc/Fc+ couple. All measurements were carried out in
degassed solutions under dry nitrogen. Freshly distilled acetonitrile was used as the
solvent and the supporting electrolyte was electrochemical grade tetrabutylammonium
hexafluorophosphate (0.1 M). The scan rate in all cases was 100 mV/s. The
electrochemical onsets were determined as the position where the current differed by 2
µA from the baseline. The highest occupied molecular orbital (HOMO) and lowest
unoccupied molecular orbital (LUMO) energy levels were calculated from the oxidation
and reduction onsets respectively according to a published equation.228
6.2.3. X-Ray Diffraction Methods
Powder diffraction data were collected at room temperature using instruments and
procedures as discussed in the X-ray diffraction methods section of Chapter 2.
76 6.2.4. Photovoltaic Methods
The following experiments were conducted by Eric D. Peterson, Wanyi Nie, and
Gregory Smith of the Wake Forest University Dept. of Physics and the Wake Forest
University Center for Nanotechnology and Molecular Materials.
A general procedure for fabrication of a solar cell device. ITO-coated glass slides
(Delta Technologies) were cleaned by sonication in acetone and isopropanol for 20
minutes each, followed by ozone cleaning for 30 minutes. A solution of PEDOT:PSS
(Clevios P – H.C. Starck) at 1:1 PEDOT:PSS solution to deionized water was spin coated
onto the slides at 4000 RPM (resulting in a 40 nm layer). The films were then baked in a
vacuum oven at 100 C for 30 minutes. Polymer solutions were then spin coated onto the
PEDOT:PSS coated substrates. Solutions were prepared by mixing polymer and 1,2- dichlorobenzene (8 mg/mL-10 mg/mL), then they were heated (80 °C - 100 °C) and stirred for 24 hr. The solutions were then filtered while hot (0.45 µm PVDF (Millipore)),
and spin coated at 1500 RPM for 40 s. The films were set to dry for 30 minutes and then
placed under vacuum for thermal deposition of electrodes (2 nm LiF/100 nm Aluminum).
The active area of the device is 38 mm2. All film thicknesses and surface profiles were
determined via a JEOL JSPM-5200 operating in AFM tapping mode. The current-voltage
(J-V) characteristics were measured with a Keithley 260 digital source meter under simulated air mass (AM) 1.5 solar irradiation of 100 mW/cm2 (Oriel 150W Xenon Light
Source). The light intensity was calibrated with a NREL calibrated reference cell
(Newport). The external quantum efficiency (EQE) curve was measured using a 300 W
Oriel Xenon light source passed through an Oriel Cornerstone 260 monochramotor, a
77 Merlin lock-in amplifier, a calibrated Si UV detector, and a SR 570 low noise current
amplifier.
6.3. Synthesis
4,7-Dibromo-2,1,3-benzothiadiazole (21),229 4,7-dibromo-2,1,3-pyridinethia-
diazole (22),230 4,7-dibromo-2,1,3-benzoselenaadiazole (23),231 4,7-dibromo-2,1,3-
pyridine-selenaadiazole (24),231 and 4,7-dibromo-2,1,3-benzoxadiazole (25)232 were synthesized according to literature procedures. The non-stannylated 4,8- didodecyloxybenzo[1,2-b:4,5-b’]dithiophene (29) and 4,8-bis(2-ethylhexyloxy)benzo
[1,2-b:4,5-b’]dithiophene (30) were synthesized according to the published procedures.233-234 4,4-Bis(2-ethylhexyl)-2,6-bis(trimethylstannyl)-4H-cyclopenta-[2,1-
b;3,4-b’]dithiophene (33) and 1,3-dibromo-5-octylthieno[3,4-b]pyrrole-4,6-dione (38a)
and 1,3-dibromo-5-(2-ethylhexyl)thieno[3,4-b]pyrrole-4,6-dione (38b) were synthesized
according to the published procedures.235-237
Undecan-6-yl methanesulfonate (26). To a dry 500 mL round-bottom flask containing
250 mL of dichloromethane was added undecan-6-ol (30.0 g, 0.174 mol), and methane-
sulfonylchloride (14.0 mL, 0.181 mol). Triethylamine (26.0 mL, 0.186 mol) was then
added dropwise to the solution via syringe. After stirring for one hour at room
temperature, the solvent was removed in vacuo, and the oily residue was extracted with
diethyl ether (500 mL) and washed with 3 x 250 mL of water. The organic layer was
dried over anhydrous MgSO4, filtered and evaporated. The yellow/brown oil was purified by flash chromatography (9:1 hexane:dichloromethane) to give the title compound. Yield
1 (31.6 g, 72.5 %). H-NMR (CDCl3), δ (ppm): 4.69 (quintet, 1H), 2.99 (s, 3H), 1.74 – 1.63
78 13 (m, 4H), 1.45-1.22 (m, 12H), 0.893 ppm (t, 6H). C-NMR (CDCl3), δ (ppm): 84.36,
39.26, 35.05, 32.23, 25.38, 23.26, 14.85 ppm.
N,N-Diethylthiophene-3-carboxamide (27). 3-Thiophenecarbonyl chloride (13.2 g,
0.09 mol) was dissolved in methylene chloride (45 mL) and added drop-wise at 0oC to a solution of diethylamine (25 mL) in methylene chloride (25 mL). The solution was stirred at 0oC for 2 hours and then at RT overnight. Diethylamine (10 mL) was added and
mixture was stirred for another 2 hours. The diethylamine hydrochloride precipitate was
filtered off and the organic phase was extracted with water. The solution was dried over
magnesium sulfate and evaporated to give a brown oil. (14.1 g, 85%). Characterization of
the product is consistent with the published data.122 One pot procedure. 3-
Thiophenecarboxylic acid (7.0 g, 0.055 mol) and thionyl chloride (5.0 mL, 0.068 mol)
were added to a round bottom flask containing methylene chloride (200 mL) and this was cooled to 0 °C. Triethylamine (15 mL) was then added drop-wise over 15 minutes resulting in the formation of a white precipitate. The mixture was allowed to warm to room temperature. After 30 minutes diethylamine (8 mL) was added drop-wise over 10 minutes. The mixture was stirred for additional 30 minutes at room temperature. The methylene chloride was evaporated, then ether was added and the triethylamine hydrochloride precipitate was filtered and washed with a small amount of ether. The ether was then evaporated to leave a brown oil (8.6 g, 86 %). Characterization of the product was consistent with the published data.233
4,8-Dihydrobenzo[1,2-b;4,5-b’]dithiophene-4,8-dione (28). Compound 27 (14.1 g,
0.077 mol) was added to a 2-neck round bottom flask that was charged with dry THF (50 mL). 1.6M n-Butyllithium in hexanes (51 mL, 0.082 mmol) was added drop-wise over 30
79 minutes at 0oC. The mixture was allowed to stir at 0oC for 30 minutes and then at RT for
2 hours. The mixture was poured over ice and allowed to stand for 4 hours. The
precipitate was filtered and washed with water and methanol and dried in air overnight.
Typical yields range from 75-92 %. Characterization of the product was consistent with
the published data.233
4,8-Bis(1-ethylhexyloxy)benzo[1,2-b:4,5-b’]dithiophene (31). Compound 28 (4.0 g,
18.1 mmol) was added to a flask containing Zn dust (2.6 g, 39.8 mmol) and NaOH (85.0 mL, 25 %) solution. The green mixture was allowed to reflux for 1 hr. The color changed to orange and 3-octylmethanesulfonate (7.3 g, 35 mmol) and tetrabutylammonium bromide (600 mg, ~10 mol %) were added. After 2 hours additional portions of 3- octylmesylate (1.34 g, 6.4 mmol) and Zn dust (1.2 g, 18.3 mmol) were added and the mixture was refluxed overnight. After cooling, the mixture was quenched with H2O and separated with ether. The organic phase was dried over MgSO4 and evacuated to yield an
1 orange oil. (4.40 g, 54%). H-NMR (CDCl3), δ (ppm): 7.47 (d, 2H); 7.33 (d, 2H); 4.52 (m,
2H); 1.73 (m, 8H); 1.51 (m, 4H); 1.30 (m, 8H) 1.03 (m, 6H); 0.89 (m, 6H). 13C-NMR
(CDCl3), δ (ppm): 143.1, 132.4, 130.5, 125.5, 120.7, 83.7, 33.7, 32.1, 26.9, 25.1, 22.6,
14.0, 9.6. MS (EI): calc’d 446.23, found (M+1)+, 447.3.
4,8-Bis(undecan-6-yloxy)benzo[1,2-b:4,5-b’]dithiophene (32). Compound 28 (4.4 g,
20 mmol) was added to a flask containing zinc powder (3.4 g, 52 mmol), tetrabutylammonium bromide (2.0 g, 6.2 mmol) and 60 mL of 25% NaOH solution. The reaction was stirred and heated to reflux for 1 hr, and then 6-undecanylmethanesulfonate
(15.0 g, 60 mmol) was added. The reaction was stirred for 2 hr at reflux, giving an orange suspension. An additional amount of Zn powder (1.2 g, 20 mmol) was added to ensure
80 completion of the reaction, and the mixture was refluxed overnight (~16 hr). The reaction
mixture was poured into water and extracted with ethyl ether, dried over MgSO4, filtered
and evaporated to give a yellow oil (8.6 g, 81 %). Analysis of this material by GC/MS
showed a 95:5 mixture of the product (M/Z = 530), and an impurity (M/Z = 514). The
impurity can be removed via flash chromatography (pure hexanes ramping to 8:2
1 hexanes:dichloromethane), resulting in 5.5 g (52 %) of pure 32. H-NMR (CDCl3), δ
(ppm): 7.44 (d, 2H), 7.30 (d, 2H), 4.56 (quintet, 2H), 1.75-1.60 (m, 8H), 1.55 – 1.38 (m,
13 8H), 1.38-1.15 (m, 16H), 0.89 ppm (t, 12H). C-NMR (CDCl3), δ (ppm): 143.11, 132.42,
130.44, 125.51, 120.73, 82.57, 34.31, 32.09, 25.07, 22.64, 14.05 ppm.
General procedure for stannylation of compounds (34), (35), (36) and (37).
Compounds 29-32 in dry THF (20 equiv. by wt.) were cooled to -78oC in an acetone/dry
ice bath. n-Butyllithium (2.2 equiv, 1.6 M) in hexanes was added dropwise. The solution was stirred at -78 °C for 30 minutes and then at RT for 2 hours. The solution was then cooled to -78 °C and freshly prepared trimethyltin chloride solution (2.4 equiv, 20% by wt. in THF) was added dropwise and the solution was allowed to stir at RT overnight.
The solution was poured into water and extracted with ethyl ether. The solution was washed with water and the organic phase was dried over anhydrous MgSO4 and
evacuated to give a waxy yellow solid (> 95 % yield). White powders could be obtained
by triturating with EtOH. No difference in purity was observed via NMR spectroscopy,
nor were there differences observed in subsequent polymerization reactions.
2,6-Bis(trimethyltin)-4,8-(1-dodecyl-oxy)benzo[1,2-b:4,5-b’]dithiophene (34). Yield;
1 64 % H-NMR (CDCl3), δ (ppm): 7.52 (s, 2H); 4.30 (t, 4H); 1.89 (m, 4H); 1.59 (m, 4H);
13 1.23-1.43 (m, 32H); 0.89 (t, 6H); 0.46 (s, 18H). C-NMR (CDCl3), δ (ppm): 143.2,
81 140.5, 134.5, 133.0, 128.0, 73.6, 32.0, 30.6, 29.8, 29.7, 29.5, 29.4, 26.2, 22.7, 14.2, -8.3.
119 Sn-NMR (CDCl3), δ (ppm) relative to SnMe3Cl (164), -33.99.
2,6-Bis(trimethyltin)-4,8-bis(2-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene (35).
1 Yield; 73 %. H-NMR (CDCl3), δ (ppm): 7.53 (s, 2H); 4.20 (d, 4H); 1.54-1.64 (m, 4H);
13 1.33-1.88 (m, 18H); 1.04 (t, 6H) 0.96 (t, 6H) 0.46 (s, 18H). C-NMR (CDCl3), δ (ppm):
143.3, 140.4, 133.9, 132.9, 128.0, 75.7, 40.7, 30.6, 29.3, 24.0, 23.2, 14.2, 11.4, -8.3.
119 Sn-NMR (CDCl3), δ (ppm) relative to SnMe3Cl (164), -33.91.
2,6-Bis(trimethyltin)-4,8-bis(1-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene (36).
1 Yield; 87 %. H-NMR (CDCl3), δ (ppm): 7.53 (s, 2H); 4.58 (m, 2H); 1.74 (m, 8H); 1.56
13 (m, 6H); 1.33 (m, 8H); 1.05 (m, 6H) 0.90 (m, 6H) 0.44 (s, 18H). C-NMR (CDCl3), δ
(ppm): 141.8, 139.8, 134.4, 133.8, 128.7, 83.2, 33.7, 32.2, 27.0, 25.1, 22.7, 14.1, 9.7, -
119 8.3. Sn-NMR (CDCl3), δ (ppm) relative to SnMe3Cl (164), -34.18.
2,6-Bis(trimethylstannyl)-4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene
1 (37). Yield; 84 %. H-NMR (CDCl3), δ (ppm): 7.49 (m, 2H), 4.61 (quintet, 2H), 1.75-
1.62 (m, 8H), 1.55 – 1.41 (m, 8H), 1.37-1.15 (m, 16H), 0.89 (t, 12H), 0.43 ppm (m, 18H).
13 C-NMR (75 MHz, CDCl3): δ = 141.27, 139.21, 133.87, 133.27, 128.17, 82.34, 35.03,
119 32.96, 25.94, 23.62, 15.11, -7.08 ppm. Sn NMR (CDCl3): δ (ppm) relative to SnMe3Cl
(164), -34.30.
General procedure for polymer synthesis of P1-P14. Under ambient atmosphere in a
5 mL microwave tube equipped with a stir bar was added the bis(trimethyltin) monomer
(0.5 mmol) along with the dibromo monomer (0.485 mmol) and 2 mL of chlorobenzene.
The tube was stirred for 5 minutes and tetrakis(triphenylphosphine)palladium(0) (2.5-5
mol %) was added and the tube was capped and set in the microwave at 200 °C for 10
82 minutes. The viscous gel was precipitated in methanol and filtered. The solid was then
added to a Soxhlet thimble and subject to extractions with hexanes (6 hrs), THF (24 hrs)
and finally chloroform (24 hrs). The chloroform extract was evaporated almost to
completion and methanol was added to precipitate the polymer, which was filtered and
dried under vacuum for 24 hours.
poly[(4,8-bis(1-dodecyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzothiadiazole-4,7-diyl] (P1). (Yield from CHCl3 extract, 5-30%). FT-IR (cm ): 2917
(s), 2849 (s), 1577 (m), 1524 (m), 1489 (m), 1450 (s), 1400 (m), 1354 (s), 1273(m), 1177
(s), 1038 (br), 908 (m), 854 (m), 816 (s), 750 (w), 718 (m), 689 (m). GPC (TCB, 135oC):
Mn = 4,760 g/mol, Mw = 6,310 g/mol, PDI = 1.33. λmax (1,2-dichlorobenzene): 598 nm.
poly[(4,8-bis(2-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzothiadiazole-4,7-diyl] (P2). (Yield from CHCl3 extract, 5-20%). FT-IR (cm ): 2951
(m), 2916 (s), 2850 (s), 1573 (m), 1523 (m), 1487 (m), 1447 (s), 1397 (m), 1351 (s),
1257(w), 1175 (s), 1030 (br), 906 (m), 852 (w), 817 (s), 715 (w), 688 (w). GPC (TCB,
o 135 C): Mn = 2,880 g/mol, Mw = 3,430 g/mol, PDI = 1.19. λmax (1,2-dichlorobenzene):
579 nm.
poly[(4,8-bis(1-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzothiadiazole-4,7-diyl] (P3). (Yield from CHCl3 extract, 56%). FT-IR (cm ): 2951
(m), 2916 (s), 2852 (s), 1575 (m), 1523 (m), 1486 (m), 1448 (s), 1396 (m), 1337 (s),
1257(w), 1178 (s), 1019 (br), 906 (m), 853 (w), 818 (s), 715 (w), 688 (w). GPC (TCB,
o 135 C): Mn = 27,100 g/mol, Mw = 68,800 g/mol, PDI = 2.54. λmax (1,2-dichlorobenzene):
637 nm.
83 poly[(4,8-bis(1-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 pyridinethiadiazole-4,7-diyl] (P4). (Yield from CHCl3 extract, 20 %). FT-IR (cm ): 2940
(m), 2924 (s), 2854 (m), 1547 (s), 1522 (m), 1439 (s), 1433 (s), 1339 (m), 1301 (m), 1178
(m), 1110 (m), 1072 (m), 1020 (s), 914 (m), 847 (m), 767 (m). λmax (CHCl3): 665 nm.
poly[(4,8-bis(1-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzoselenadiazole-4,7-diyl] (P5). (Yield from CHCl3 extract, 52 %). FT-IR (cm ): 2945
(m), 2920 (s), 2853 (s), 1562 (m), 1521 (m), 1455 (m), 1438 (s), 1396 (m), 1338 (s), 1287
(w), 1114 (s), 1019 (br), 9010 (m), 852 (w), 827 (s), 719 (w). λmax (CHCl3): 659 nm.
poly[(4,8-bis(1-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 pyridineselenadiazole-4,7-diyl] (P6). (Yield from CHCl3 extract, 31 %). FT-IR (cm ):
2940 (m), 2924 (s), 2854 (m), 1547 (s), 1522 (m), 1439 (s), 1433 (s), 1339 (m), 1301 (m),
1178 (m), 1110 (m), 1072 (m), 1020 (s), 914 (m), 847 (m), 767 (m). λmax (CHCl3): 736
nm.
poly[4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzothiadiazole-4,7-diyl] (P7). (Yield from CHCl3 extract, 70 %). FT-IR (cm ): 2945
(m), 2925 (s), 2854 (m), 1578 (s), 1523 (m), 1487 (m), 1444 (s), 1339 (m), 1254 (m),
1179 (m), 1118 (m), 1019 (s), 908 (m), 833 (m), 817 (s), 720 (m). GPC: Mn = 31.2 kg/mol, PDI = 2.57. λmax (chlorobenzene): 639 nm.
poly[4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 pyridinethiadiazole-4,7-diyl] (P8). (Yield from CHCl3 extract, 34 %). FT-IR (cm ): 2938
(m), 2927 (s), 2850 (m), 1549 (s), 1521 (m), 1438 (s), 1440 (s), 1338 (m), 1307 (m), 1172
(m), 1108 (m), 1072 (m), 1021 (s), 916 (m), 844 (m), 768 (m). λmax (chlorobenzene): 694 nm.
84 poly[4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzoselendadiazole-4,7-diyl] (P9). (Yield from CHCl3 extract, 63 %). FT-IR (cm ):
2945 (m), 2920 (s), 2853 (s), 1562 (m), 1521 (m), 1455 (m), 1438 (s), 1396 (m), 1338 (s),
1287 (w), 1114 (s), 1019 (br), 9010 (m), 852 (w), 827 (s), 719 (w). λmax (chlorobenzene):
678 nm.
Poly[4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 pyridineselenadiazole-4,7-diyl] (P10). (Yield from CHCl3 extract, 21 %). FT-IR (cm ):
2945 (m), 2922 (s), 2857 (m), 1549 (s), 1520 (m), 1439 (s), 1431 (s), 1338 (m), 1302 (m),
1179 (m), 1110 (m), 1075 (m), 1022 (s), 910 (m), 843 (m), 767 (m). λmax (chlorobenzene):
741 nm.
Poly[4,8-bis(1-pentylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-
-1 benzoxadiazole-4,7-diyl] (P11). (Yield from CHCl3 extract, 51 %). FT-IR (cm ): 2945
(m), 2925 (s), 2855 (m), 1596 (m), 1537 (s), 1449 (s), 1375 (m), 1340 (m), 1260 (m),
1182 (m), 1116 (m), 1026 (s), 1009 (s), 924 (m), 891 (m), 825 (s), 799 (m), 723 (m).
GPC: Mn = 47.2 kg/mol, PDI = 3.81. λmax (chlorobenzene): 653 nm.
poly[(4,8-bis(2-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-(5-
octylthieno[3,4-b]pyrrole-4,6-dione)-1,3-diyl] (P12). Characterization of the polymer is
238-240 consistent with the literature procedures. Yield (from CHCl3 extract, 56%). λmax
(CHCl3): known, 627 nm; found, 634 nm.
poly[(4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b:3,4-b’]dithiophene)-2,6-diyl-alt-(5-
octylthieno[3,4-b]pyrrole-4,6-dione)-1,3-diyl] (P13). Yield (from CHCl3 extract, 49 %).
1 H-NMR (500 MHz, CDCl3), δ (ppm): 7.98 (m, 2H); 3.70 (t, 2H); 2.03 (br, 4H); 1.72 (br,
2H); 1.61 (br, 4H); 1.40-1.30 (br, 12H); 1.10-0.93 (br, 15H) 0.90 (m, 4H) 0.77 (br, 9H);
85 13 0.67 (br, 6H). C-NMR (125 MHz, CDCl3), δ (ppm): 162.67, 160.57, 140.30, 136.33,
134.08, 128.00, 54.52, 43.03, 38.70, 35.42, 34.25, 31.84, 29.29, 29.22, 28.66, 28.58,
27.57, 27.06, 22.89, 22.67, 14.12, 14.09, 10.76. FT-IR (cm-1): 2917 (s), 2853 (s), 1736
(m), 1697 (s), 1533 (s), 1456 (m), 1427 (m), 1379 (s), 1186 (m), 1072 (m), 1042 (s), 750
(s). GPC: Mn = 10,300, Mw = 12,800, PDI = 1.24. λmax (CHCl3): 653 nm.
poly[(4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b:3,4-b’]dithiophene)-2,6-diyl-alt-(5-
ethylhexyl[3,4-b]pyrrole-4,6-dione)-1,3-diyl] (P14). Yield (from CHCl3 extract, 32 %).
1 H-NMR (500 MHz, CDCl3), δ (ppm): 7.99 (m, 2H); 3.64 (br, 2H); 2.03-1.98 (br, 4H);
1.98-1.90 (br, 2H) 1.61-1.55 (br, 1H); 1.60-1.30 (br, 6H); 1.15-0.95 (br, 18H); 0.85-0.60
13 (br, 18H). C-NMR (125 MHz, CDCl3), δ (ppm): 162.96, 160.51, 140.35, 136.28, 134.10,
127.95, 54.51, 47.77, 35.92, 35.12, 34.31, 29.65, 28.60, 28.53, 27.59, 23.93, 23.14, 22.88,
14.57, 13.67, 13.43, 10.71. FT-IR (cm-1): 2953 (m), 2920 (s), 2854 (s), 1737 (m), 1697
(s), 1534 (s), 1456 (m), 1427 (m), 1377 (s), 1321 (m), 1186 (m), 1065 (s), 1011 (m), 750
(s). λmax (CHCl3): 652 nm.
86 CHAPTER 7
SYNTHESIS, CHARACTERIZATION AND
PHOTOVOLTAIC PROPERTIES OF POLYMERS P1-P3
Christopher M. MacNeill, Robert C. Coffin, Eric Peterson, Gregory L. Smith, Ronald E.
Noftle and David L. Carroll
The following chapter was accepted as a manuscript to the Journal of Nanotechnology,
2011. All of the research presented was conducted by Christopher M. MacNeill with help
from Robert C. Coffin. The photovoltaic device data was completed by Eric Peterson and
Gregory Smith. The manuscript was prepared by Christopher M. MacNeill and Robert C.
Coffin and edited by David L. Carroll and Ronald E. Noftle
87 7.1. Synthesis of Polymers P1-P3
The synthetic routes to the electron-donor monomers are shown in Schemes 6 and
7. For the amounts of starting materials used in the following syntheses, see Chapter 6.
Starting from 3-thiophenecarboxylic acid, we developed a new one-pot procedure for
accessing the synthetic intermediate N,N-diethylthiophene-3-carboxamide (27).
O O SOCl2 O OH n-BuLi TEA N(CH2CH3)2 S
CH2Cl2 THF S 0oC, 1hr S HN(CH2CH3)2 S RT, 24hr O 27 28
Scheme 6: The synthesis of 4,8-dihydrobenzo[1,2-b;4,5-b’]dithiophene-4,8-dione 28.
3-Thiophenecarboxylic acid is allowed to react with one equivalent of thionyl chloride and excess triethylamine in dichloromethane. After 30 minutes of stirring, one equivalent of diethylamine was added to the reaction mixture containing 3- thiophenecarbonyl chloride to form the desired product. The HCl generated by this reaction reacts with the remaining triethylamine to form a triethylamine hydrochloride salt which precipitates from the reaction and drives it forward.
OR OR O 1. Zn dust 1. n-BuLi 20% NaOH o S S S THF, -78 C (H3C)3Sn Sn(CH3)3 2. R-Br or R-OMs S 2. Sn(CH ) Cl S S TBAB 3 3 RT, 24hr OR O reflux, 24hr OR R = 1-dodcecyl = 34 29-32 28 2-ethylhexyl = 35 1-ethylhexyl = 36 6-undecyl = 37
Scheme 7: The synthesis of the bis-stannylated monomers 34-37.
88 N,N-Diethylthiophene-3-carboxamide (27) is then allowed to react with one equivalent of
n-butyllithium at 0oC to give 4,8-dihydrobenzo[1,2-b;4,5-b’]dithiophene-4,8-dione (28)
(Scheme 6). Reaction of compound (28) with zinc metal in sodium hydroxide solution
reduced the dione to the corresponding diol and deprotonated it, giving the alkoxy
species, which reacts with either an alkyl bromide or alkyl mesylate to give the 4,8-
dialkoxybenzodithiophene compounds (29-32). Reactions of compounds (29-32) with n-
butyllithium and quenching with trimethyltin chloride solution gave the bis-stannylated
monomers (34-37) (Scheme 7). Compounds 29-32 and 34-37 were prepared using procedures similar to those in the literature.233-234
S OC H OC12H25 N N 12 25 S S (H3C)3Sn Sn(CH3)3 S S n OC H OC12H25 12 25 34 P1
S O NN O S N N S Pd(PPh3)4 S + (H3C)3Sn Sn(CH3)3 S chlorobenzene S n Br Br microwave O 200oC, 10 min O 21
P2 35
O S N N O S S (H3C)3Sn Sn(CH3)3 S S n O O
36 P3
Scheme 8: The synthesis of polymers P1-P3.
89 The purity of monomers 34-37 was confirmed by 119Sn-NMR spectroscopy (Appendix
B8-B11), which is a very useful technique for determining whether any trace monostannane impurities exist in the monomers. These impurities are detrimental to the polymerization reactions because they can interfere with the polymers step-growth mechanism.
Polymers P1-P3 were prepared by microwave-assisted Stille cross-coupling polymerization of the bis-stannylated monomers 34-36 with 4,7-dibromo-2,1,3- benzothiadiazole (21) in chlorobenzene using tetrakis(triphenylphosphine)palladium(0)
((Ph3P)4Pd) as the catalyst (Scheme 8). Microwave heating was used because it is more efficient than conventional heating methods, and it has also been reported to give higher
molecular weights.241-245 The polymers were precipitated by adding the mixture to
methanol. The product was collected by filtration, and transferred to a Soxhlet extractor,
where the material was washed with hexanes and extracted with chloroform. The
chloroform-soluble fraction was isolated to ensure the material was sufficiently soluble
for the preparation of OPV devices. In all cases, material remained in the extraction
thimble after chloroform extraction; however, the amount of this material was highly
variable. For P1 and P2, yields from the chloroform soluble fractions were often less
than 10 %, while for P3, yields as high as 55 % were obtained. Assuming no cross
linking of the polymer had occurred, the fact that material remained in the extraction
thimble after chloroform extraction meant that the chloroform fraction contained material
with the highest molecular weight that is soluble in chloroform. The molecular weights of
the these fractions were determined by gel permeation chromatography (GPC) at 135 °C
using 1,2,4-trichlorobenzene as the solvent and the results are summarized in Table 1.
90 P1, P2 and P3 were found to have weight average molecular weights (Mw) of 6.3, 3.4 and
68.8 kg/mol respectively.
7.2. Thermogravimetric Analysis of P1-P3
Thermogravimetric analysis was performed on polymers P1-P3 under argon at
5 °C/min as shown in Figure 25. The results indicate that the polymers have similar thermal stabilities with the onsets of degradation ranging from 268 and 278 °C. This degradation has been attributed to the loss of the alkoxy side chains from the BDT unit
(P1; calc., 53.3 %; found, 48.5 %: P2-P3; calc., 44.3 %; found, 38.8 %), which is supported by the fact that P1, which has a twelve carbon side chain, loses a larger weight percentage compared with P2 and P3, which have eight carbon side chains.
110
100
90
80
70 Weight %
60
50
40 50 150 250 350 450 550 Temperature (oC)
Figure 25: The TGA curve of P1 (black), P2 (blue) and P3 (red) under argon at 5oC/min.
Complete loss of the polymer structure was observed above 440oC. These high
degradation temperatures make the polymer suitable for organic-based solar cell devices.
91 7.3. UV-Vis Spectroscopy of P1-P3
UV-visible absorption spectra for polymers P1-P3 in dichlorobenzene solution
(DCB) are shown in Figure 26. P2 is considerably blue-shifted from P1, with a λmax of
579 nm compared to 598 nm for P1. This is indicative of a lower molecular weight material which was confirmed using GPC analysis. The shape of the absorption profile
Absorbance (a.u.)
300 400 500 600 700 800 Wavelength (nm)
Figure 26: The UV-vis absorption spectra of P1 (black), P2 (blue) and P3 (red) in DCB.
for P3 is very different from those of P1 and P2 with a very sharp, low-energy feature dominating the spectrum, resulting in a λmax of 637 nm. This sharp, low-energy feature
has been seen in other low band gap copolymers and is indicative of high molecular
weight and often better solar cell performance.241, 246-248
7.4. Electrochemistry of P1-P3
Cyclic voltammetry measurements were made on polymer films of P1-P3. The
films were prepared by drop-casting chloroform solutions of the polymers onto a glassy
carbon electrode (Figure 27). The onsets of the oxidation and reduction potentials for the
92 three polymers were comparable because they share a common backbone. These results
are summarized in Table 3. The oxidation onsets, determined as the point where the
current differed from the baseline by 2 µA, were found to be 0.15, 0.13 and 0.12 V for P1,
P2 and P3 giving rise to HOMO levels of -4.95, -4.93 and -4.92 eV respectively.
25μA
Current Current
-2.2 -1.7 -1.2 -0.7 -0.2 0.3 0.8 Potential vs. Fc/Fc+ (V)
Figure 27: The cyclic voltammograms of P1 (black), P2 (blue) and P3 (red) films drop-
cast from chloroform solution.
Table 3: Table of results from electrochemical and UV-visible spectroscopy
measurements of polymers P1-P3.
opt elect λmax ΔEg Eox onset HOMO Ered onset LUMO ΔEg (nm) (eV) (V) (eV) (V) (eV) (eV) P1 600 1.67 0.15 -4.95 -1.72 -3.08 1.87 P2 575 1.74 0.13 -4.93 -1.62 -3.18 1.75 P3 637 1.72 0.12 -4.92 -1.59 -3.21 1.71
Similarly, the reduction onsets were found to be -1.72, -1.62 and -1.59 V for P1, P2 and
P3 giving rise to LUMO levels of -3.08, -3.18 and -3.21 eV respectively. These results give electrochemical band-gaps of 1.87, 1.75 and 1.71 eV for P1, P2 and P3.
93 7.5. X-Ray Powder Diffraction of P1-P3
To give insight into the internal packing structure of the polymers, powder x-ray diffraction (PXRD) was used. Samples were mounted on a loop and two frames were measured at 2θ = 20 and 50° with exposure time of 180 seconds/frame. The integrated
diffraction patterns are shown in Figure 25. For the inset powder diffraction pattern, 10
frames were measured at 2θ = 25° with an exposure time of 180 seconds/frame, then they were added together. This was necessary to detect the d2-spacing of P3. The intensities
of the diffraction patterns decrease and diffraction peak widths increase from P1 to P2 to
P3, indicating that structural order within the solid polymers decreases from P1 to P3.
However, the degree of order has been shown to be dependent on Mw, with high Mw materials showing less order. The peaks at low angle (2θ = 4.15° for P1, 5.7° for P2 and
5.5° for P3) are assigned to the intermolecular distance between the polymer main chains separated by an alkoxy side chain (d1-spacing, see Figure 28a). The 1-dodecyloxy chain
(P1) gives the longest d1-spacing at 21.3 Å while the shorter 2-ethylhexyloxy (P2) and 3-
octyloxy (P3) side chains give small d1-spacings (15.5 and 16.1 Å, respectively). A plot of the low angle d-spacing vs. no. of carbon atoms for the three polymers gave a slope of
0.98 Å / carbon atom, which is indicative of an interdigitation packing mode (see Figure
28b), not an end-to-end packing mode like that seen in polythiophenes.249-251 The peak at
2θ = 8.3° for P1 corresponds to the second order peak of 2θ = 4.15°. The peaks at 2θ =
24.9° for P1, 24.5° for P2 and 23.8° for P3 correspond to the π-π stacking distances (d2- spacings) 3.58, 3.63 and 3.74 Å for P1, P2 and P3 respectively. Despite the increase in the π-π stacking distance due to the 3-octyl chain, it is worth noting that P3 still has a
94 smaller π-π stacking distance than poly(3-hexylthiophene);252 thus, our method of increasing Mw is likely not detrimental to solar cell performance.
Figure 28: (a) The integrated powder diffraction patterns for P1 (black), P2 (blue) and
P3 (red). Inset: 10 frames added together for P3. (b) A model of packing for P3.
7.6. Photovoltaic Properties of P1-P3
The photovoltaic characteristics of the polymers were determined using a standard
bulk heterojunction device architecture – ITO/PEDOT:PSS/P1-P3:PC61BM/LiF/Al. The
devices (0.38 cm2) were fabricated under an inert atmosphere and tested in air. The active
layers were deposited from 1,2-dichlorobenzene solutions (8 mg/mL for P2 and P3, 10
mg/mL for P1) and the optimal weight ratios of polymer:PC61BM was determined to be
1:2.5 for P1 and P3 and 1:2.2 for P2. The active layer thickness for the optimal devices
as determined by atomic force microscopy (AFM) were 130, 50 and 100 nm for P1, P2
and P3 respectively. Due to the poor solubility of P2 and its low Mw, thicker films could not be achieved even at the lowest spin speeds. The current-voltage (J-V) curves for the
95 best devices for each polymer are shown in Figure 29, and the results are summarized in
Table 4.
Figure 29: Current-voltage characteristics of BHJ solar cells based on P1 (black), P2
(blue) and P3 (red) with PC61BM.
The open circuit voltages (Voc) are similar for the three polymers, near 0.7 V, which is
consistent with the HOMO levels determined by cyclic voltammetry. The short circuit
2 current density (Jsc) for P1 and P2 are similarly low (near 1 mA/cm ), while Jsc is much
2 higher for P3 at 8.93 mA/cm . The fill factors (FF) increase with increasing Mw peaking
at 0.46 for P3. Consequently, P3 has a much higher power conversion efficiency (PCE)
peaking at 2.91 % compared with 0.31 % for P1 and 0.19 % for P2.
Table 4: Photovoltaic characteristics of best devices prepared from P1-P3 and PC61BM.
Voc Jsc FF PCE (V) (mA/cm2) (%) P1 0.69 1.22 0.42 0.33 P2 0.71 0.81 0.33 0.19 P3 0.73 8.93 0.46 2.99
96 The EQE spectra for the P1 and P2 devices (seen in Figure 30) show poor current
generation across the spectrum with peak EQE less than 12 %. P3, on the other hand,
shows EQE above 30 % from 330-670 nm, with a peak near 51 % at 370 nm. Between
400 and 600 nm, the EQE dips, indicating that current production could be enhanced by
253 using PC71BM instead of PC61BM as PC71BM absorbs in this range.
Figure 30: External quantum efficiency spectra of BHJ solar cells based on P1 (black),
P2 (blue) and P3 (red) with PC61BM.
P3 outperforms P1 and P2 across the board, with higher Voc, Jsc, FF and PCE. It is worth
noting that the P3 solar cells were prepared from pristine DCB solution without the use of optimization techniques such as annealing or additive processing, that could greatly
enhance the PCE.
7.7. Conclusion
We prepared and characterized two new low band gap copolymers based on BDT
and BT that employ branched side chains at the 4- and 8-positions, poly[(4,8-bis(2-
97 ethylhexyloxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-benzothiadiazole-4,7- diyl] (P2) and poly[(4,8-bis(3-octyloxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-
2,1,3-benzothiadiazole-4,7-diyl] (P3) as well as the previously reported linear side chain analog, poly[(4,8-didodecyloxy)benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-2,1,3-benzo- thiadiazole-4,7-diyl] (P1). Surprisingly, transitioning from the linear 1-dodecyl side chain
P1 to the branched 2-ethylhexyl side chain P2 results in a decrease in Mw; however, by moving the ethyl branch in one position relative to the polymer backbone P3, we observe a dramatic increase in Mw to 68.8 kg/mol compared with 6.3 kg/mol for P1 and 3.4 kg/mol for P2. This results in vastly different optical properties, with the appearance of a sharp low energy feature in the UV-visible absorption spectrum of P3 that is not present in the spectra of P1 and P2. Despite the increase in the - stacking distance due to the
3-octyl branch in P3 relative to P1 and P2, the increased Mw results in an order of magnitude increase in the PCE of the bulk heterojunction solar cells. We observe a peak
PCE of 2.91 % for devices based on P3 and PC61BM with minimal optimization indicating that this material has the potential to make highly efficient solar cells. By varying the side chain, we were able to take a polymer that was present in the literature, but had poor device characteristics and improve on them by simply changing the side chain. Also, by changing the side chain we were able to make a high molecular weight polymer with excellent solubility and solution processability. Using a 3-octyl side chain may now be a way of increasing the Mw in conjugated polymers; many of which have not reached their full potential as organic photovoltaics because of poor processability and insufficient Mw.
98 CHAPTER 8
SYNTHESIS, CHARACTERIZATION AND
PHOTOVOLTAIC PROPERTIES OF POLYMERS P4-P11
Christopher M. MacNeill, Robert C. Coffin, Wanyi Nie, Eric Peterson, Gregory L. Smith,
Ronald E. Noftle and David L. Carroll
Some of the results from the following chapter were accepted for publication in
Macromolecular Rapid Communications, 2011. All of the research presented was conducted by Christopher M. MacNeill with help from Robert C. Coffin. The photovoltaic device data was completed by Wanyi Nie, Eric Peterson and Gregory Smith.
The manuscript was prepared by Wanyi Nie and Robert C. Coffin and edited by David L.
Carroll and Ronald E. Noftle.
99 8.1. Synthesis of Polymers P4-P11
Monomers 22-24 were used in the synthesis of polymers P4-P6 because they have better electron-withdrawing properties than monomer 21 and consequently the band gap of the ensuing polymers will be lowered. With a lower band gap, the polymers can absorb more photons further into the red region of the visible spectrum. Polymers P4-P6
(Scheme 9) were synthesized according to the same procedure outlined in Chapter 7. The yields of chloroform extract from the polymerizations varied for the different comonomers used. For the polymers based on the pyridine monomers (P4 and P6), the yields were low (< 30 %), while the benzene based monomer (P5), gave good yields
(82 %). These results are due to the lower solubility of nitrogen containing rings compared with their benzene counterparts. Since the polymers weren’t appreciably soluble
S N N
Br Br N 22
Se X N N O NN O S Pd(PPh3)4 S Br Br + (H3C)3Sn Sn(CH3)3 S chlorobenzene Y S n microwave 23 O 200oC, 10 min O Se N N 36 Br Br X=S,Y=N; P4 N X=Se,Y=C;P5 X=Se,Y=N;P6 24 Scheme 9: The synthesis of polymers P4-P6. in chloroform, a bulkier side chain on the BDT unit was necessary to ensure greater solubility. The side chain chosen was a 6-undecyloxy side chain (Scheme 6). Unlike 2- ethylhexyloxy (35) and 3-octyloxy (36), the 6-undecyloxy group (37) is symmetric, but
100 since the branch is larger and has been moved in one position on the polymer backbone
relative to the 2-ethylhexyloxy, one would expect the bulkiness of this side chain to
frustrate aggregation and enhance the solubility. This guarantees that a higher Mn material can be obtained, which is beneficial to OPV performance; however, the bulky side chain could prevent ordering in the solid state, which may be detrimental to device performance. 2,6-Bis(trimethylstannyl)-4,8-bis(6-undecyloxy)benzo[1,2-b:4,5-b’] dithiophene (37) was co-polymerized with 4,7-dibromo-2,1,3-benzothiadiazole (21) to give polymer (P7) in good yield (70 %). The polymer was soluble at >15 mg/mL at room temperature in chlorinated aromatic solvents and had a number average molecular weight
(Mn) of 31.2 kg/mol and a polydispersity index (PDI) of 2.57 (gel permeation
chromatography, GPC, 135 °C in 1,2,4-trichlorobenzene).
S N N
Br Br
21
S N N
Br Br N 22 X Se O NN O N N S Pd(PPh3)4 S + (H3C)3Sn Sn(CH3)3 Br chlorobenzene n Br S Y S microwave o O 23 O 200 C, 10 min
Se N N 37 X=S,Y=C; P7 Br Br X=S,Y=N; P8 N X=Se,Y=C;P9 24 X=Se,Y=N;P10 X=O,Y=C; P11 O N N
Br Br 25
Scheme 10: The synthesis of polymers P7-P11.
101 Polymers (P8-P11) were synthesized using other electron-withdrawing monomers
(22-25) with 2,6-bis(trimethylstannyl)-4,8-bis(6-undecyloxy)benzo[1,2-b:4,5-b’] dithiophene (37) (Scheme 10). The polymer yields were similar to those for the previous polymers bearing the 3-octyloxy side chain. The benzothiadiazole (BT) based polymer
(P7) and pyridinethiadiazole (PT) based polymer (P8) were the most soluble and gave the highest yield (70 % and 63 %), while the benzoselenadiazole (BSe) based polymer (P9) and pyridineselenadiazole (PSe) based polymer (P10), which contained the pyridine ring, were the least soluble and had lower yields (34 % and 21 %). Polymer (P11) had a moderate yield (51%) and was soluble at >10 mg/mL at room temperature in chlorinated aromatic solvents and found to have a number average molecular weight (Mn) of 47.2 kg/mol and a polydispersity index (PDI) of 3.81.
(a.u.)Absorbance
300 400 500 600 700 800 900 1000 Wavelength (nm)
Figure 31: The UV-Vis absorption spectra of P3 (red), P4 (black), P5 (green) and P6
(pink) in DCB.
102 Figure 31 shows the UV-visible absorption spectrum of P3-P6. Exchanging the
BT monomer with a better accepting BSe, PT or PSe monomer can successfully decrease the band gap and shift the λmax further into the red region. Due to the limited solubility of
P4-P6, the polymers were not further characterized and attention was focused on P7-P11,
with the more solubilizing 6-undecyl side chain.
8.2. Thermogravimetric Analysis of P7-P11
Thermogravimetric analysis was performed on polymers P7-P11 under argon at
5 °C/min (Figure 32). The results show that the polymers have similar stability with their
onsets of degradation ranging from 250 to 270 °C. These results are consistent with the
loss of side chains from the BDT polymer backbone (calculated: 36-41 % for P7-P11,
found: 38-41 %). Complete loss of the polymer structure was observed after 375oC.
These high degradation temperatures would also render P7-P11 suitable for use in
polymer solar cell devices.
110
100
90
80
Weight % 70
60
50 0 100 200 300 400 500 600 Temperature (oC) Figure 32: The TGA curve of P7 (black), P8 (blue), P9 (orange), P10 (green) and P11
(red) under argon at 5oC/min.
103 8.3. UV-Visible Spectroscopy of P7-P11
UV-visible absorption spectra for polymers P7-P11 in dichlorobenzene solution
(DCB) can be seen in Figure 33. P11 is slightly red-shifted from P7, due to the oxygen atom on the oxadiazole acceptor being more electronegative than the sulfur atom on the thiadiazole acceptor, which gives a slightly deeper LUMO and lowers the band gap.
Similar results can be seen with other BDT and 2,7-carbazole-based copolymers.242,254
The λmax of P11 is 653 nm compared to 639 nm for P7. P9 is further red-shifted from P7
and has a λmax of 678 nm, owing to the selenium atom replacing the sulfur atom. The
larger selenium atom causes the N-Se-N bond and the C-N double bond of the
selenadiazole group to be more strained giving rise to a lower band gap and a subsequent
red shift.255-259 P8 and P10 are further red-shifted from P9 due to the nitrogen in the ring
of the pyridinethiadiazole and the pyridineselenadiazole. The nitrogen atom makes the
260 acceptor even more electron poor and gives rise to a lower band gap. The λmax of P8 and P10 is 694 and 741 nm, respectively. The solution optical band gaps generated from
Figure 33: The UV-vis absorption spectra of P7 (black), P8 (blue), P9 (orange), P10
(green) and P11 (red) in DCB.
104 the absorbance onset are 1.72, 1.59, 1.62, 1.47 and 1.68 eV. The shape of the absorption
profiles for P7-P11 are very similar to that from P3. This is again indicative of a high
molecular weight polymer.
8.4. Electrochemistry of P7-P11
Cyclic voltammetric measurements were made on polymer films of P7-P11. The films were prepared by drop-casting chloroform solutions of the polymers onto a glassy carbon electrode (Figure 34). The onset oxidation and reduction potentials for the five polymers were comparable because they share a common backbone. These results are summarized in Table 5.
50μA
Current Current
-2.2 -1.2 -0.2 0.8
Potential vs Fc/Fc+ (V)
Figure 34: The cyclic voltammograms of P7 (black), P8 (blue), P9 (orange), P10 (green) and P11 (red) films drop-cast from chloroform solution.
105 The oxidation onsets, determined as the point where the current differed from the baseline by 2 µA, were found to be 0.35, 0.44, 0.16, 0.31 and 0.50 V for P7, P8, P9, P10 and P11 giving rise to HOMO levels of -5.15, -5.24, -4.96, -5.11 and -5.30 eV respectively. The reduction onsets were found to be -1.53, -1.29, -1.34, -1.10 and -1.25 V for P7, P8, P9, P10 and P11 giving rise to LUMO levels of -3.27, -3.51, -3.46, -3.70 and
-3.55 eV respectively. These results give electrochemical band-gaps of 1.88, 1.73, 1.50,
1.41 and 1.75 eV for P7, P8, P9, P10 and P11.
Table 5: Table of results from electrochemical and UV-visible spectroscopy measurements of polymers P7-P11.
opt elect λmax ΔEg Eox onset HOMO Ered onset LUMO ΔEg (nm) (eV) (V) (eV) (V) (eV) (eV) P7 639 1.72 0.41 -5.21 -1.38 -3.42 1.77 P8 694 1.59 0.46 -5.26 -1.23 -3.57 1.69 P9 678 1.62 0.11 -4.91 -1.39 -3.41 1.60 P10 741 1.47 0.34 -5.14 -1.10 -3.70 1.44 P11 653 1.68 0.52 -5.32 -1.23 -3.57 1.75
8.5. X-Ray Powder Diffraction of P7-P11
Powder x-ray diffraction was used to give insight into the internal packing structure of the polymers. Samples were mounted on a loop and two frames were measured at 2θ = 20 and 50° with exposure time of 180 seconds/frame. The integrated diffraction patterns are shown in Figure 35. The intensities of the diffraction patterns decrease and diffraction peaks broaden from P11 to P8 to P7 to P9 and P10, indicating that structural order within the solid polymers decreases in the order P11 > P8 > P7 > P9
> P10. The peaks at low angle (2θ = 5.0° for P11, 5.35° for P8, 5.65° for P9, 5.55° for P7
106 and 5.40° for P10) are assigned to the intermolecular distance between the polymer main
chains separated by an alkoxy side chain (d1-spacing). The benzoxadiazole based
polymer P11 gave the longest d1-spacing at 17.7 Å. The PT polymer P8 and PSe polymer
P10 gave the next smallest d1-spacings at 16.5 and 16.4 Å, respectively, while both of the
BT and BSe polymer P7 and P9 gave the shortest d1-spacings (15.9 and 15.6 Å). These
values are comparable to those for 4,8-bis(2-ethylhexyloxy)BDT copolymers, since this
spacing is related to side chain length. A low intensity peak at 2θ = 23.6° corresponding
to a d2-spacing (π-stacking distance) of 3.8 Å is also observed for P11, and not for any of
the other polymers. This d2-spacing is larger than that of other BDT copolymers (d2 ~ 3.6
Å) likely owning to the bulk of the 6-undecyl side chain.
d2 d1 = 16.5 Å
d1 = 17.7 Å
d1
Intensity
d1 = 15.9 Å
d = 15.6 Å 1 d2 = 3.8 Å d1 = 16.4 Å
3 8 13 18 23 28
2θ (degrees) Figure 35: The powder diffraction patterns for P7 (black), P8 (blue) and P9 (orange),
P10 (green) and P11 (red).
107 The inset spectrum is a theoretical model of the potential packing diagram of the polymer
in the solid state. The polymer likely adopts an interdigitation packing mode, not an end- to-end packing mode. This is due to the distance of d1-spacing. If the polymer existed in
an end-to-end packing mode, the d1-spacing would be > 20 Å.
8.6. Photovoltaic Properties of P7-P11
The photovoltaic characteristics of the polymers were determined using a standard
bulk heterojunction device architecture – ITO/PEDOT:PSS/P7-P11:PC71BM/LiF/Al. The
devices (0.38 cm2) were fabricated under an inert atmosphere and tested in air. The
results were an average of at least eight devices. A LiF hole-blocking layer was used
because it was found early-on in our study to improve Vocs by ~ 0.06 V. Similar Jsc’s
were observed for P8, P9 and P11. Polymers P9 and P10 showed lower Vocs (~0.67-0.75
V) compared to P7, P8 and P11 (>0.80 V). This is due to the low band gap nature of the
selenium based acceptor monomer. The LUMO levels are too deep, and the HOMO is too
large, and the subsequent decrease in the band gap gives rise to a decrease in Voc. The
lower band gap nature of the P9 and P10 polymers should have an increase in Jsc, which wasn’t apparent in our J-V curves (Figure 36).
This, however, may be due to the decrease in crystallinity owing to the effect of the selenium atom in the acceptor compared to the sulfur atoms, as observed in the PXRD data (Figure 32). The FF is comparable for P7, P9 and P11 (> 0.46), but relatively low for P8 and P10 (0.43-0.39). This may result from the ability of the pyridine nitrogen of the acceptors to coordinate palladium during the polymer synthesis.
108 6
) 4 2 2
0 (mA/cm ‐2 ‐4
Density ‐6
‐8 ‐10
Current ‐12 ‐14 ‐0.5 0 0.5 1 Voltage (V)
Figure 36: Current-voltage characteristics of BHJ solar cells based on P7 (black), P8
(blue), P9 (orange), P10 (green) and P11 (red) with PC71BM.
Once, the palladium is entrained in the polymer, it is difficult to remove.261 The palladium may cause the excitons to recombine before the have a chance to reach the
PCBM acceptor. Alternatively, the material may not be crystalline enough to give good charge carrier mobility and a low fill factor may result. The device characteristics of P7-
P11 are summarized in Table 6
The EQE spectra for the P7-P11 devices (Figure 37) show good current generation across the spectrum with peak EQE at 50 % for P7 between 350 and 700 nm.
P8 shows an EQE at ~30 % from 330-750 nm. P9 showed 40 % EQE up to 500 nm, and slowly the EQE dropped to 10% at 750 nm. P10 had the lowest EQE of any of the polymers, at 25 % between 350 and 800 nm. P11 showed a similar EQE to P9 with much better current generation between 600 and 700 nm. This explains the increase in PCE of
0.65 % from P9 to P11. P7 outperformed all of the other polymers in terms of Jsc and
PCE when spin coating out of pristine DCB.
109
60
50
40
30
EQE (%) 20
10
0 300 400 500 600 700 800 900 Wavelength (nm)
Figure 37: External quantum efficiency spectra of BHJ solar cells based on P7 (black),
P8 (blue), P9 (orange), P10 (green) and P11 (red) with PC71BM.
Table 6: Photovoltaic characteristics of best devices prepared from P7-P11 and PC71BM.
Voc (V) Jsc (mA/cm2) FF PCE (%) P7 0.80 10.23 0.49 3.87 P8 0.83 6.36 0.43 2.27 P9 0.75 7.55 0.46 2.59 P10 0.67 4.53 0.39 1.13 P11 0.92 7.02 0.52 3.25
8.7. Solvent Additive Processing of Polymer P11
Using 1,2-dichlorobenzene (DCB) as the solvent, P11:PC71BM weight ratios were varied from 1:1 to 1:2.2. The Vocs and FF are relatively constant at ~ 0.92 V and
0.48, respectively, at P11:PC71BM ratios of 1:1.5 or greater. The Jsc peaks at ~7.3
mA/cm2 and the power conversion efficiency (PCE) peaks at an average of 3.06 % at a
ratio 1:1.5. The Voc is > 0.2 V higher for devices fabricated from P11 which is consistent
110 with a deeper HOMO level as determined by cyclic voltammetry. Using this optimal
P11:PC71BM ratio, devices were fabricated from chlorobenzene (CB). Despite and improvement in the Vocs and FFs to ~ 0.97 V and 0.55, respectively, a precipitous drop in
2 Jsc to 2.64 mA/cm resulted in lower average PCEs of ~ 1.41 %.
To further improve device performance, additive processing with P11 was
investigated.262-263 Two such additives that have been shown to greatly improve device
performance are 1,8-diiodooctane(DIO)264 and 1-chloronapthalene (CN).265 Both
additives are high boiling and slow the film-drying process. They differ in that DIO has
been shown to promote polymer aggregation, which increases the domain sizes within the
film, while CN prevents polymer aggregation and decreases phase separation. Given
P11’s high solubility and poor tendency to aggregate, DIO was initially investigated as an
additive in both CB and DCB. However, DIO processing led to poorly reproducible
device performance. The effects of CN depended greatly on the host solvent.
A comparison of the PV characteristics of devices prepared from pristine CB and
DCB with those prepared with CN additive are shown in Figures 38a and b, while the
best J-V and EQE curves for each condition are shown in Figures 38c and d. Using DCB
as the host solvent, devices were fabricated from solutions containing 1 % and 2 % CN.
Both loadings resulted in a decrease in average device PCE from 3.06 % without additive
to 2.42 % with 1 % CN and 1.82 % with 2 % CN. When CB is used as the host solvent
the effect of the additives is quite different. Average PCE for devices prepared from CB
solution without additive was 1.41 %.
111
Figure 38: Summary of chlorobenzene ratio on device performance. (a) Summary of open circuit voltage and short circuit current density. (b) Summary of fill factor and power conversion efficiency. Points represent the average of at least eight devices with standard deviation. (c) The best current-voltage curves, and (d) the best external quantum efficiency curves for each condition. This figure is reproduced with permission from
Wanyi Nie.
The addition of 1, 2 and 4 % CN results in average PCEs of 2.82, 5.65, and
4.01 % respectively (Appendix B12). The best device fabricated using 2 % CN in CB
2 showed a Voc of 0.887 V, Jsc of 13.6 mA/cm , FF of 0.508, and PCE of 6.05 %. The improvements in PCEs upon addition of CN to CB are a result of dramatically improved
2 2 Jsc from an average of 2.64 mA/cm for pristine CB to an average of 12.43 mA/cm for
112 CB with 2 % CN. For both host solvents, the Voc and FF drop upon addition of the CN. A
loss in Voc is not uncommon with additive processing, presumably a result of increased ordering stabilizing the HOMO level of the polymer. However, increases in Jsc are
typically accompanied by increases in FF, which is a result of improvements in active
layer morphology that allow for improved charge separation and collection. The external
quantum efficiency for the best device fabricated from CB with 2 % CN is above 55 %
from 350 to 670 nm reaching a maximum of 69 % at 590 nm.
8.8. Conclusion
In summary, the synthesis and characterization of polymers P4-P11 as well as the
device performance of polymers P7-P11 has been carried out. For polymers P4-P6, the yields were relatively low because the 3-octyl side chain is not bulky enough to decrease crystallinity and solubilize the polymers. After addition of a bulky 6-undecyl side chain, aggregation was prevented, enabling the production of high molecular weight, freely soluble copolymers P7-P11. UV-visible spectroscopy showed a decrease in band gap as the electron-withdrawing nature of the acceptor increased. HOMO and LUMO levels were calculated using cyclic voltammetry for P7-P11 and indicated that the selenium based acceptors vastly decrease the band gap compared to the sulfur and oxygen-based acceptors. OPV devices were fabricated for polymers P7-P11. Vocs were low for the
selenium-based acceptor polymers P9-P10 compared to P7, P8 and P11, which is normal for lower band gap materials. The fill factor for the pyridine-based acceptor polymers P8 and P10 were lower than the benzene-based acceptor polymers P7, P9 and P11. Two possible explanations are poor packing of the bulky 6-undecyl side chain or palladium
113 contamination due to the pyridine nitrogen atoms ability to coordinate palladium. At an optimized P11:PC71BM ratio, solvent additive processing was employed to further improve device performance. Using DCB as the host solvent, the addition of CN resulted in a decrease in PCE relative to devices prepared from pristine solvent. Conversely, devices prepared from a solution of 2% CN in CB resulted in a dramatic improvement in
PCE to an average of 5.65 %, compared with 1.41 % from pristine chlorobenzene. The optimized devices have high Voc, but a FF around ~0.5 limits the overall PCE of these devices.
114 CHAPTER 9
SYNTHESIS, CHARACTERIZATION AND
PHOTOVOLTAIC PROPERTIES OF POLYMERS P12-P14
Christopher M. MacNeill, Robert C. Coffin, Eric Peterson, Ronald E. Noftle and David
L. Carroll
Some of the results from the following chapter were published as a manuscript in the journal, Synthetic Metals, 2011 DOI: 10.1016/j.synthmet.2011.02.010. Stylistic variations are due to the requirements of the journal. All of the research presented was conducted by Christopher M. MacNeill with help from Robert C. Coffin. The photovoltaic device data was completed by Eric Peterson. The manuscript was prepared by Christopher M. MacNeill and Robert C. Coffin and edited by David L. Carroll and
Ronald E. Noftle.
115 9.1. Synthesis of Polymers P12-P14
Polymer P12238-240 was synthesized according to the same procedure outlined in
Chapter 7 and used as the control during this study. The bis-stannylated monomer, 2,6- bis(trimethyltin)-4,8-bis(2-ethylhexyl-oxy)benzo[1,2-b:4,5-b’]dithiophene (35), was polymerized with 1,3-dibromo-5-octylthieno[3,4-b]pyrrole-4,6-dione (38a)235-236 in
chlorobenzene under microwave radiation using tetrakis(triphenylphosphine)
palladium(0) (Pd(PPh3)4) as the catalyst to give P12 (Scheme 11). Polymers P13-P14
were synthesized using the same microwave procedure. Reacting 2,6-Bis(trimethyltin)-
4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b;3,4-b’]dithiophene (33),237 with either 1,3-
dibromo-5-octylthieno [3,4-b]pyrrole-4,6-dione (38a) or 1,3-dibromo-5-(2-ethylhexyl)
thieno[3,4-b]pyrro-le-4,6-dione (38b), 235-236 gave polymers P13-P14 (Scheme 12).
C8H17 C H 8 17 O N O O O O N O Pd(PPh3)4 S S + (H3C)3Sn Sn(CH3)3 chlorobenzene S microwave S S n Br Br 200oC, 10 min S O O
38a P12 35
Scheme 11: The synthesis of polymer P12.
The polymers were subsequently precipitated, washed with methanol and hexane,
and then extracted with chloroform in a Soxhlet extractor. Gel-permeation
chromatography (135 °C, 1,2,4-trichlorobenzene) of polymer P13 precipitated from the
chloroform extract revealed a number average molecular weight (Mn) of 10.3 kg/mol and
polydispersity index (PDI) of 1.24.
116
R Pd(PPh ) O N O 3 4 S + chlorobenzene S S n microwave Br S Br o Me3Sn S S SnMe3 200 C, 10 min O N O
38a-b 33 R R=n-octyl P13 R = 2-ethylhexyl P14
Scheme 12. The synthesis of polymers P13-P14.
The polymers are very soluble (>10 mg/mL) in chlorinated solvents such as chloroform, chlorobenzene and dichlorobenzene.
9.2. Thermogravimetric Analysis of P12-P14
Thermogravimetric analysis was performed on polymers P12-P14 under argon at
10 °C/min and the results can be seen in Figure 39. P12 is stable up to 280oC, after
which, there is a decrease in weight attributed to the loss of the alkoxy side chains on the
BDT unit (calc., 31.7 %; found, 31.4 %). A second weight decrease is observed between
450 and 500oC, which is attributed to loss of the octyl side chain on the thienopyrroledione monomer (calc., 15.8 %; found, 15.2 %). The TGA of P12 is
comparable to the literature TGA trace.238 Polymers P13-P14 showed greater thermal
stability, with their onsets of degradation ranging from 375 to 400°C. These results are
consistent with the loss of the ethylhexyl side chains from the CPDT monomer and loss of either an octyl side chain or an ethylhexyl side chain from the thienopyrroledione monomer (calculated: P13, 50.3 %, P14; 50.5 %, found: P13; 49.5 %, P14; 51.3 %).
Degradation of the polymer structure was observed after 500oC for all three polymers.
117
120
100
80
60
Weight % 40
20
0 0 100 200 300 400 500 600
Temperature (oC)
Figure 39: The TGA curve of P12 (blue), P13 (black) and P14 (red) under argon at
10oC/min.
Differential scanning calorimetry shows no discernable thermal transitions between 0 and
250 °C (Appendix B12) for polymer P13. This indicates that thermal annealing of the
device substrate, in order to align the polymer chains, is not required because the polymer
does not have a glass transition temperature.
9.3. UV-Visible Spectroscopy of P12-P14
Normalized UV-visible absorption spectra of P12, P13 and P14 in chloroform
239 solution can be seen in Figure 40. The λmax for P12 in solution is 633 nm (lit. 627 nm) compared to 653 nm, for polymers P13 and P14. This is due to the lower band gap of the
CPDT donor monomer compared to BDT. The absorption onset for P12 in solution is
118 685 nm (lit. 685 nm)238 compared to 712 nm for P13-P14, corresponding to an optical band gap of 1.74 eV, 0.07 eV lower than P12.
Absorbance (a.u.)
300 400 500 600 700 800 900 Wavelength (nm)
Figure 40: The UV-vis absorption spectra of P12 (blue), P13 (black) and P14 (red) in chloroform solution.
9.4. Electrochemistry of P12-P14
Cyclic voltammetry of drop-cast polymer films was employed to estimate the
HOMO and LUMO energy levels of P12-P14 (Figure 41). The onset of oxidation for P12 was 0.41 V, which corresponds to a HOMO level of -5.21 eV (lit. 5.4 eV).239 The onset
of oxidation of P13-P14 was ~0.27 V corresponding to a HOMO level of -5.07 eV. As
seen in the figure the onset is similar to that for PBDTTPD and because of this a similar
Voc in the OPV devices was anticipated. The onset of reduction for P12-P14 is -1.67 V which corresponds to a LUMO level of -3.13 eV (lit. - 3.4 eV). This gives an electrochemical band gap of 2.14 eV for P12 (lit. 2.03, 1.81 eV)238,240 and 1.94 eV for
P13-P14. Table 7 shows the optical and electrochemical characteristics of P12-P14.
119
20µA
Current
-2.5 -1.5 -0.5 0.5 1.5 + Potential (V vs. Fc/Fc )
Figure 41: The cyclic voltammograms of P12 (blue), P13 (black) and P14 (red) films
drop-cast from chloroform solution.
Table 7: Table of results from electrochemical and UV-visible spectroscopy
measurements of polymers P12-P14.
opt elect λmax Eg Eox onset HOMO Ered onset LUMO Eg (nm) (eV) (V) (eV) (V) (eV) (eV) P12 633 1.81 0.41 -5.21 -1.67 -3.13 2.14 P13 653 1.74 0.27 -5.07 -1.67 -3.13 1.94 P14 653 1.74 0.27 -5.07 -1.67 -3.13 1.94
9.5. X-Ray Powder Diffraction of P12-P14
The internal structure of the polymers was investigated using X-ray powder
diffraction (Figure 42). For P12, one low intensity peak was seen at 2θ = 5.7. This
corresponds to a d-spacing of 20.8 Å (lit. 20.9 Å)238. This d-spacing relates to the intermolecular distance between polymer chains in the same plane. The peak at 2θ = 24.8
120 238 (d2 = 3.60 Å, lit. 3.6 Å ) corresponds to the π-π stacking distance between polymer
chains in adjacent planes. For P13 and P14, similar powder diffraction spectra can be seen. Four low intensity diffraction peaks were observed at 2θ = 5.7, 7.7, 9.4 for P13 and
2θ = 5.6 and 8.3 for P14. These 2θ values give rise to d1-spacings of 15.6 Å, 11.4 Å, 9.4
Å for P13 and 15.9 Å and 10.6 Å for P14, respectively. The peaks at d1 = 15.6 Å for P13
and 15.9 Å for P14, correspond to the intermolecular distance between polymer chains.
The slight difference in length arises from the different side chains on the TPD acceptor.
For P13, the side chain is an octyl group, while for P14, the side chain is an ethylhexyl
group. The peaks at d3 = 11.4 Å and 10.6 Å, for P13 and P14, respectively, relate to the
second order peak of the powder pattern.
200 d1 = 20.8 Å 180 d1 = 15.9 Å
160
140 d3 = 10.6 Å d2 = 3.67 Å 120
100 d1 = 15.6 Å
Intensity d3 = 11.4 Å 80 d2 = 3.77 Å 60
40
20 d = 3.60 Å 2 0 3 8 13 18 23 28 2θ (degrees)
Figure 42: The powder diffraction patterns for P12 (blue), P13 (black) and P14 (red) on loop.
If the d1 peak corresponds to the (1,0,0) plane, the d3 peak will correspond to the (2,0,0)
plane. This finding is indicative of long range order in the polymer. The peaks at d2 =
121 3.77 Å for P13 and 3.67 Å for P14, correspond to the π-π stacking distance between polymer chains in adjacent planes.
9.6. Photovoltaic Properties of P12 and P13
The photovoltaic characteristics of the polymer were determined using a standard bulk heterojunction device architecture as reported in Chapters 6-7. The composition of
2 the device is ITO/PEDOT:PSS/P12-P13:PC61BM/Al. The 0.38 mm devices were
fabricated under an inert atmosphere and tested in air. The active layer of P12 was spin-
coated from a chlorobenzene solution (8 mg/mL) with a weight ratio of 1:1.5
P12:PC61BM. The polymer showed a Voc of 0.78 V, a Jsc of 6.51 mA/cm2 and a FF of
0.45 and a PCE of 2.31. Due to the similarity of the results for P13 and P14, only the photovoltaic characteristics of P13 were investigated (Table 8).
2
0
)
2 -0.1 0.1 0.3 0.5 0.7 0.9
-2
-4
-6
Current Density (mA/cm -8
-10 Voltage (V)
Figure 43: Current-voltage characteristics of BHJ solar cells based on 1:1.5 (w:w)
P12:PC61BM (blue) and 1:2.5 (w:w) P13:PC61BM (black) with 2 % DIO additive.
122 The active layer of P13 was deposited from a chlorobenzene solution (9 mg/mL) and the
weight ratio of P13:PC61BM was varied from 1:1 to 1:3 in increments of 0.5 to determine
the optimal fullerene loading. As seen in Table 9, by increasing the P13:PC61BM from
1:1 to 1:2.5, the Voc remains relatively constant while the Jsc increases from 3.95 to 8.02
mA/cm2 and PCE increases from 1.02 to 2.43 %. At 1:3 the device efficiencies
dramatically decrease. In order to further improve device efficiencies, the 1:2.5
P13:PC61BM devices were processed using 2% 1,8-diiodooctane (DIO) as a solvent
additive.237 Figure 43 shows an average of the J-V curves for these devices. Processing with DIO leads to a decrease in Voc from 0.92 to 0.87 V but improvements in Jsc and fill factor (FF) lead to an improved average PCE of 3.15 %. The Voc of these devices is
similar to that reported for PBDTTPD238-240 consistent with the HOMO level determined
by CV measurement. The EQE of the DIO processed devices is shown in Figure 44.
60
50
40
30
EQE % 20
10
0 350 450 550 650 750 Wavelength (nm)
Figure 44: External quantum efficiency spectra of BHJ solar cells based on 1:1.5 (w:w)
P12:PC61BM (blue) and 1:2.5 (w:w) P13:PC61BM with 2% DIO additive (black).
123 For P12, The EQE is flat (around ~ 40-45 %) between 475-600 nm. The current
integrates to 7.14 mA/cm2 for the EQE of P12. This is slightly greater than the short
circuit current generated from the device (6.51 mA/cm2). This indicates decent current
production compared to the upper limit of the polymer. The EQE peaks at ~ 45-50 % between 550 and 675 nm for P13 and current is generated beyond 700 nm.
Table 8: Photovoltaic characteristics of best devices prepared from P12-P13 and
PC61BM.
2 Voc (V) Jsc (mA/cm ) FF PCE (%) P12 0.78 6.51 0.45 2.31 P13 0.92 8.02 0.34 2.43
Table 9: A comparison of the photovoltaic characteristics of P13 at different (w:w) ratios
PC61BM and using additive processing. The best device PCE can be seen in parenthesis.
2 P13:PCBM Voc (V) Jsc (mA/cm ) FF PCE (%) 1:1 0.89 3.95 0.29 1.02 1:1.5 0.92 6.81 0.34 2.05 1:2 0.90 7.65 0.34 2.30 1:2.5 0.92 8.02 0.34 2.43 1:3 0.80 6.24 0.28 1.27 1:2.5 2% DIO 0.87 8.70 0.43 3.15 (3.47)
9.7. Conclusion
In conclusion, we have successfully synthesized a new copolymer, P13, using a
Stille coupling procedure under microwave radiation and compared it to a known
polymer P12. The UV-visible spectrum indicates that the P13 polymer absorbed further
into the red region than P12, indicating a lower band gap. Cyclic voltammetry revealed
124 that the HOMO and LUMO energy levels were consistent with the optical band gap observed in the absorbance spectrum. Powder x-ray diffraction of P12-P14 showed that the polymer had long range order. The J-V and EQE curves showed that P13 had a high
2 Voc (0.92 V) and Jsc (8.02 mA/cm ), and a good PCE (2.43), while the best device in 2% solvent additive gave a PCE of 3.47. These results indicate that P13 has potential application as a donor polymer in BHJ solar cells.
125 CONCLUSIONS
There has been on-going research into the study of new materials with applications in areas such as sustainability, renewability and green technologies. These materials have become imperative to our survival as a society, now more than ever.
Inorganic/organic polymeric materials, such as coordination polymers for use as heterogeneous catalysts, may offer a way to make new organic materials in faster time periods, under milder conditions with a catalyst that can be recycled in subsequent reactions. Simple filtration and drying allows for the coordination polymer to be re-used up to three times without loss of activity. Since homogeneous catalalysts are expensive, difficult to recover, and lose catalytic effectiveness, coordination polymers may provide environmentally cost-effective synthetic routes.
Nine new lanthanide-based coordination polymers were synthesized and characterized using a variety of methods such as single crystal x-ray diffraction, powder diffraction, elemental analysis, TGA, infrared spectroscopy and solid state photoluminescence. The heterogeneous catalytic activity of coordination polymers 1-2 and 7-9 were assessed in the Biginelli reaction. The Biginelli reaction is a cyclocondensation reaction of an aldehyde, urea and a dicarbonyl compound to give a substituted dihydropyrimidinone, which have been used as anti-virals and in other medicinal applications. Coordination polymers 1-2 showed low yields of dihydropyrimidinone product in the Biginelli reaction because of the mild basicity of the frameworks due to the 2,5-thiophenedicarboxylate linker. Coordination polymers 5-9 were synthesized using a less basic linker, 2,3,5,6-tetrafluoroterephthalic acid, and
126 catalytic activity in the Biginelli reaction doubled. These results showed that, by
synthesizing a coordination polymer using a less basic organic linker with electron
withdrawing groups, the lanthanide metal ion became more electropositive and a better
Lewis acid.
Organic polymeric materials promise the same improvements as
inorganic/organic polymeric materials in terms of sustainability and renewability. The
use of organic polymeric materials as photovoltaic devices to harvest sunlight and turn it
into electricity, will help relieve our dependence on foreign oil and cut down on the
release of carbon dioxide gas which contributes to global warming. Today, silicon-based
devices dominate the solar cell market due to their high power conversion efficiencies;
however, organic photovoltaics offer a cheaper alternative to conventional silicon-based
devices, with an ease in processing conditions due to the ability of the organic
photovoltaics to be solution-cast printed or spray-coated.
Twelve new low band gap polymers were synthesized and characterized using a
variety of methods such as 1H-NMR, 13C-NMR, infrared spectroscopy, gel permeation chromatography, TGA, UV-visible spectroscopy, cyclic voltammetry and powder x-ray diffraction. Polymers P1 and P2 were insoluble in all common chlorinated solvents. The molecular weight of polymer P2 increased ten fold when the ethyl branch was moved one carbon closer to the BDT backbone (P3). This slight change was enough to frustrate stacking of the polymer in the solid state, enabling it to stay in solution longer and continue to grow in molecular weight. The soluble donor monomer having a 3-octyl side
chain polymerized with alternate electron-withdrawing co-monomers yielded co-
polymers P4-P6 that were again fairly insoluble. These polymers did show a lower
127 optical and electrochemical band gap than the P3 polymer. Moving from the soluble 3- octyl side chain donor-acceptor co-polymer P3 to a bulkier 6-undecyl donor-acceptor co- polymer P7, further increased the molecular weight of the polymer, as well as its solution processability. Device data showed an increase in EQE from 350-700 nm, as well as an increase in PCE from ~ 3 % to ~ 3.9 %. Co-polymers P8-P11 were synthesized using
similar electron-acceptor monomers as seen in P4-P6. This lowered the band gap of the
co-polymers while maintaining good solution processability, which was not observed
with co-polymers P4-P6. P11 showed a high Voc along with some crystallinity in the
powder diffraction spectrum so it was further optimized using solvent additives. After
processing with DIO and CN, this polymer-based device showed an improvement from
2.7 % efficiency to a champion efficiency of 6.05 %. With results like these and many
others, the theoretical limit of 10 % PCE for a polymer-based device is on the horizon. It
may only be a matter of time before researchers achieve this feat and polymer solar cell
production is begun on a global scale.
128 FUTURE WORK
Future work for the first project should be to assess the catalytic activity of the
coordination polymers 1-9 in other reactions besides the Biginelli reaction. This may lead
to coordination polymers 1-9 showing better activity in other systems. Other reactions
may include Lewis acid-based catalytic reactions, the Knoevenagel condensation, the
cyanosilylation of aldehydes or the epoxidation of olefins.
New lanthanide-based coordination polymers based on larger organic linkers
should be synthesized and characterized. These new coordination polymers with larger
channel sizes may have their catalytic properties evaluated by the Biginelli reaction. By
varying the size of the organic substrates, one should be able to probe for size selective
catalysis and determine whether catalysis can take place in the channels of the frameworks instead of on the surface which was observed for coordination polymers 1-9.
Future work for the second project would be to answer some of the questions that
have arisen during the research already conducted. The selenium-based polymers P9 and
P10 showed lower power conversion efficiencies compared to P3-P11. This could be due to the ability of the selenium acceptor to coordinate palladium. Rigorous steps must be taken during the polymer workup to remove palladium. Use of palladium coordinating ligands and celite filtration, combined with quantification of the palladium content in the polymers using inductively coupled plasma mass spectrometry, may determine whether it is the palladium that is inhibiting power conversion efficiency of the device.
If there is to be commercialization of organic solar cells which can be placed on the roofs of houses or windows of buildings, modules will have to be spray-coated. Initial
129 results of spray-coating polymer P11 showed good power conversion efficiencies around
3 %. As of the start of 2011, the world record efficiency for a spray coated device is ~
2.8 %. Despite this fascinating result, optimization of the polymer solar cell devices should continue in order to achieve greater efficiencies. Using solvent additive processing with spray coating should help with this optimization.
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153
APPENDIX A: CRYSTAL STRUCTURES FOR COMPOUNDS (1-9),
A full hemisphere of diffracted intensities for compounds (1-9) was measured
using graphite- monochromated MoKα radiation (= 0.71073 Å) on a Bruker SMART
APEX CCD Single Crystal Diffraction System. Lattice constants were determined with
the Bruker SAINT software package. The Bruker software package SHELXTL was used to solve the structure using “direct methods” techniques. The data was corrected for
variable absorption effects using SADABS. All stages of weighted full-matrix least-
2 squares refinement were conducted using Fo data with the SHELXTL software package.
The resulting structural parameters have been refined to convergence using counter-
weighted full-matrix least-squares techniques and a structural model which incorporated
anisotropic thermal parameters for all nonhydrogen atoms.
Crystallographic data for compounds (1), (2), and (5)-(9) have been deposited in
the Cambridge Crystallographic Data Centre: 720500, 720501, 768795-768799. These
data can be obtained free of charge via the internet at www.ccdc.cam.ac.uk/data_request
/cif, by email at [email protected]., or by contacting the Cambridge Crysta-
llographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-
336033.
154 APPENDIX A1: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (1) [La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7]
Wake Forest University X-Ray Code: a69l
Table A1-1. Crystal data and structure refinement for La2(C6H2O4S)3(ONC3H7)2 (H2O)-ONC3H7 ______Identification code a69l Empirical formula C27 H29 La2 N3 O16 S3 Formula weight 1025.53 Temperature 223(2) K Wavelength 0.71073 Å Crystal system Orthorhombic 9 Space group Pna2(1) – C 2v (No. 33) Unit cell dimensions a = 17.434(4) Å b = 11.227(3) Å c = 17.980(4) Å. Volume 3519.0(15) Å3 Z 4 Density (calculated) 1.936 g/cm3 Absorption coefficient 2.649 mm-1 F(000) 2008 Crystal size 0.16 x 0.07 x 0.02 mm3 Theta range for data collection 3.81 to 27.50° Index ranges -22≤h≤22, -14≤k≤14, -23≤l≤22 Independent reflections 8041 [R(int) = 0.0878] Completeness to theta = 27.50° 99.7 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.9489 and 0.6766 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 8041 / 37 / 470 Goodness-of-fit on F2 1.072
Final R indices [I>2sigma(I)] R1 = 0.0542, wR2 = 0.1145
R indices (all data) R1 = 0.0665, wR2 = 0.1200 Largest diff. peak and hole 3.593 and -1.537 e-/Å3 ______
155 Table A1-2. Bond lengths [Å] and angles [°] for La2(C6H2O4S)3(ONC3H7)2(H2O)- ONC3H7 ______La(1)-O(23)#1 2.391(6) O(13)-C(16) 1.245(10) La(1)-O(21) 2.400(6) O(14)-C(16) 1.275(11) La(1)-O(13)#2 2.492(6) O(21)-C(25) 1.260(12) La(1)-O(31) 2.502(6) O(22)-C(25) 1.244(12) La(1)-O(1) 2.549(8) O(23)-C(26) 1.261(11) La(1)-O(33)#3 2.553(6) O(24)-C(26) 1.263(11) La(1)-O(12)#4 2.564(6) O(31)-C(35) 1.270(11) La(1)-O(34)#3 2.869(6) O(32)-C(35) 1.260(11) La(2)-O(11)#5 2.470(6) O(33)-C(36) 1.272(11) La(2)-O(14) 2.536(6) O(34)-C(36) 1.255(10) La(2)-O(34)#6 2.538(6) C(11)-C(12) 1.392(10) La(2)-O(22) 2.539(6) C(11)-C(15) 1.514(10) La(2)-O(24)#7 2.569(6) C(12)-C(13) 1.414(10) La(2)-O(2) 2.587(7) C(13)-C(14) 1.373(11) La(2)-O(4) 2.675(5) C(14)-C(16) 1.471(11) La(2)-O(13) 2.926(7) C(21)-C(22) 1.371(10) La(2)-O(32) 2.430(6) C(21)-C(25) 1.492(11) S(1)-C(11) 1.699(9) C(22)-C(23) 1.419(11) S(1)-C(14) 1.723(9) C(23)-C(24) 1.378(11) S(2)-C(24) 1.698(8) C(24)-C(26) 1.482(11) S(2)-C(21) 1.714(9) C(31)-C(32) 1.354(10) S(3)-C(34) 1.701(8) C(31)-C(35) 1.490(10) S(3)-C(31) 1.708(9) C(32)-C(33) 1.398(10) O(11)-C(15) 1.253(11) C(33)-C(34) 1.368(10) O(12)-C(15) 1.246(11) C(34)-C(36) 1.469(10) O(1)-C(1) 1.259(13) N(1)-C(1) 1.284(14) O(2)-C(4) 1.237(12) N(2)-C(4) 1.311(14) O(3)-C(7) 1.216(16) N(3)-C(7) 1.328(17) N(1)-C(2) 1.44(2) N(2)-C(6) 1.457(16) N(1)-C(3) 1.48(2) N(3)-C(9) 1.44(2) N(2)-C(5) 1.424(18) N(3)-C(8) 1.502(19) O(4)-H(41) 0.80(10) O(23)#1-La(1)-O(13)#2 73.2(2) O(23)#1-La(1)-O(21) 131.6(2) O(21)-La(1)-O(13)#2 154.5(2)
156 O(23)#1-La(1)-O(31) 80.4(2) O(11)#5-La(2)-O(24)#7 128.4(2) O(21)-La(1)-O(31) 91.1(2) O(14)-La(2)-O(24)#7 77.6(2) O(13)#2-La(1)-O(31) 87.3(2) O(34)#6-La(2)-O(24)#7 76.59(19) O(23)#1-La(1)-O(1) 140.4(2) O(22)-La(2)-O(24)#7 141.7(2) O(21)-La(1)-O(1) 76.5(2) O(32)-La(2)-O(2) 72.6(2) O(13)#2-La(1)-O(1) 79.0(2) O(11)#5-La(2)-O(2) 133.3(2) O(31)-La(1)-O(1) 70.7(2) O(14)-La(2)-O(2) 138.2(2) O(23)#1-La(1)-O(33)#3 79.5(2) O(34)#6-La(2)-O(2) 79.5(2) O(21)-La(1)-O(33)#3 73.2(2) O(22)-La(2)-O(2) 68.7(2) O(13)#2-La(1)-O(33)#3 124.3(2) O(24)#7-La(2)-O(2) 73.5(2) O(31)-La(1)-O(33)#3 134.6(2) O(32)-La(2)-O(4) 69.6(3) O(1)-La(1)-O(33)#3 140.0(2) O(11)#5-La(2)-O(4) 70.5(2) O(23)#1-La(1)-O(12)#4 129.9(2) O(14)-La(2)-O(4) 69.9(3) O(21)-La(1)-O(12)#4 83.2(2) O(34)#6-La(2)-O(4) 137.7(3) O(13)#2-La(1)-O(12)#4 82.6(2) O(22)-La(2)-O(4) 67.4(3) O(31)-La(1)-O(12)#4 142.2(2) O(24)#7-La(2)-O(4) 142.2(3) O(1)-La(1)-O(12)#4 71.7(2) O(2)-La(2)-O(4) 120.1(2) O(33)#3-La(1)-O(12)#4 79.3(2) O(32)-La(2)-O(13) 117.2(2) O(23)#1-La(1)-O(34)#3 67.58(19) O(11)#5-La(2)-O(13) 69.0(2) O(21)-La(1)-O(34)#3 115.2(2) O(14)-La(2)-O(13) 46.85(19) O(13)#2-La(1)-O(34)#3 77.01(18) O(34)#6-La(2)-O(13) 75.28(18) O(31)-La(1)-O(34)#3 147.2(2) O(22)-La(2)-O(13) 145.9(2) O(1)-La(1)-O(34)#3 132.1(2) O(24)#7-La(2)-O(13) 65.36(19) O(33)#3-La(1)-O(34)#3 47.62(18) O(2)-La(2)-O(13) 135.5(2) O(12)#4-La(1)-O(34)#3 64.55(19) O(4)-La(2)-O(13) 103.0(2) O(32)-La(2)-O(11)#5 139.9(2) O(32)-La(2)-O(14) 74.8(2) O(11)#5-La(2)-O(14) 88.4(2) O(32)-La(2)-O(34)#6 149.5(2) O(11)#5-La(2)-O(34)#6 69.6(2) O(14)-La(2)-O(34)#6 122.1(2) O(32)-La(2)-O(22) 91.0(2) O(11)#5-La(2)-O(22) 77.0(2) O(14)-La(2)-O(22) 137.3(2) O(34)#6-La(2)-O(22) 90.2(2) O(32)-La(2)-O(24)#7 83.8(2)
157 Table A1-3. Hydrogen coordinates ( x 104) and isotropic displacement parameters (Å2x
103) for La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7 ______x y z U(eq) ______H(12) -6180 4144 8309 32 H(13) -6363 5137 7102 35 H(22) -2086 10499 3270 38 H(23) -2243 11372 2018 39 H(32) -4660 9702 7114 44 H(33) -4810 10701 8314 42 H(1) -1705 11461 4450 55 H(2A) -1772 13404 4110 115 H(2B) -1230 14185 4621 115 H(2C) -2130 14235 4731 115 H(3A) -1628 12488 6245 89 H(3B) -2023 13707 6019 89 H(3C) -1118 13582 5988 89 H(4) -3811 10979 5125 43 H(5A) -5062 11423 3709 141 H(5B) -4550 12406 3318 141 H(5C) -5122 12771 3963 141 H(6A) -3164 12543 4667 90 H(6B) -3664 13545 4280 90 H(6C) -3254 12560 3791 90 H(7) -4306 4736 5470 76 H(8A) -3042 3429 6648 131 H(8B) -3439 2161 6606 131 H(8C) -3688 3083 7228 131 H(9A) -5195 3295 5871 186 H(9B) -5089 3159 6742 186 H(9C) -4831 2117 6203 186 H(41) -3210(60) 6530(80) 5390(60) 31 ______
158 Table A1-4. Hydrogen bonds for La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7 [Å and °]. ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(4)-H(41)...O(3) 0.80(10) 2.02(10) 2.777(11) 156(10) ______
Figure A1-1: A view of the asymmetric unit of La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7 with nonhydrogen atoms represented by thermal vibration ellipsoids drawn to encompass 50% of their electron density. Hydrogen atoms omitted for clarity.
159
Figure A1-2: A view of the framework of La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7 with nonhydrogen atoms represented by arbitrarily small spheres, which are in no way representative of their true thermal motion. Hydrogen atoms omitted for clarity.
Figure A1-3: A view of the framework of La2(C6H2O4S)3(ONC3H7)2(H2O)-ONC3H7 projected down the a-axis with nonhydrogen atoms represented by arbitrarily small spheres, which are in no way representative of their true thermal motion. Hydrogen atoms omitted for clarity.
160 APPENDIX A2: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (2) [Gd2(C6H2O4S)3(OCHNMe2)2(H2O)]
Wake Forest University X-Ray Code: a23m
Table A2-1 Crystal Data and Structure refinement for Gd2(C6H2O4S)3(OCHNMe2)2 (H2O) ______Identification code a23m2m Empirical formula C24 H22 Gd2 N2 O15 S3 Formula weight 989.12 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 5 Space group P21/n [an alternate setting of P21/c – C2h Unit cell dimensions a = 17.5387(17) Å b = 10.8038(11) Å, β = 104.793(2)° c = 17.7283(18) Å Volume 3247.9(6) Å3 Z 4 Density (calculated) 2.023 g/cm3 Absorption coefficient 4.312 mm-1 F(000) 1904 Crystal size 0.07 x 0.07 x 0.02 mm3 Theta range for data collection 3.77 to 25.50° Index ranges -21≤h≤21, -13≤k≤13, -21≤l≤21 Independent reflections 6005 [R(int) = 0.0590] Completeness to theta = 25.50° 99.6 % Absorption correction Multi-scan (SADABS) Ratio Min/Max transmission 0.720921 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 6005 / 0 / 422 Goodness-of-fit on F2 1.188
Final R indices [I>2σ(I)] R1 = 0.0487, wR2 = 0.0956
R indices (all data) R1 = 0.0603, wR2 = 0.0993 Largest diff. peak and hole 2.189 and -1.710 e-/Å3 ______
161 Table A2-2. Bond lengths [Å] and angles [°] for Gd2(C6H2O4S)3(OCHNMe2)2(H2O) ______Gd(1)-O(1) 2.306(5) Gd(2)-O(4)#4 2.303(5) Gd(1)-O(2A) 2.323(5) Gd(2)-O(1A) 2.340(5) Gd(1)-O(3A)#1 2.347(5) Gd(2)-O(1B)#2 2.347(5) Gd(1)-O(4A)#2 2.359(6) Gd(2)-O(2) 2.352(5) Gd(1)-O(5) 2.373(5) Gd(2)-O(3)#5 2.382(5) Gd(1)-O(4B)#3 2.401(5) Gd(2)-O(2B)#6 2.386(5) Gd(1)-O(3B) 2.440(5) Gd(2)-O(6) 2.450(6) Gd(1)-O(4B) 2.589(5) Gd(2)-O(7) 2.645(6) Gd(1)-Gd(1)#3 3.9472(8) O(4B)-C(6B) 1.301(9) S(1)-C(5) 1.718(8) C(1)-C(2) 1.482(10) S(1)-C(2) 1.724(8) C(2)-C(3) 1.333(11) S(1A)-C(5A) 1.722(8) C(3)-C(4) 1.412(11) S(1A)-C(2A) 1.720(8) C(4)-C(5) 1.355(11) S(1B)-C(2B) 1.708(8) C(5)-C(6) 1.484(10) S(1B)-C(5B) 1.724(8) C(1A)-C(2A) 1.501(10) O(1)-C(1) 1.265(9) C(2A)-C(3A) 1.350(11) O(2)-C(1) 1.243(9) C(3A)-C(4A) 1.414(11) O(3)-C(6) 1.256(9) C(4A)-C(5A) 1.361(11) O(4)-C(6) 1.257(9) C(5A)-C(6A) 1.475(10) O(1A)-C(1A) 1.262(9) C(1B)-C(2B) 1.495(10) O(2A)-C(1A) 1.244(9) C(2B)-C(3B) 1.352(11) O(3A)-C(6A) 1.244(9) C(3B)-C(4B) 1.403(11) O(4A)-C(6A) 1.285(9) C(4B)-C(5B) 1.348(11) O(1B)-C(1B) 1.253(9) C(5B)-C(6B) 1.474(10) O(2B)-C(1B) 1.256(9) O(5)-C(7) 1.212(11) O(3B)-C(6B) 1.240(9) O(6)-C(10) 1.206(11) N(1)-C(7) 1.299(12) O(1)-Gd(1)-O(3A)#1 105.48(19) N(2)-C(10) 1.282(13) O(2A)-Gd(1)-O(3A)#1 145.0(2) N(1)-C(9) 1.472(13) O(1)-Gd(1)-O(4A)#2 92.65(19) N(1)-C(8) 1.486(14) O(2A)-Gd(1)-O(4A)#2 73.9(2) N(2)-C(12) 1.466(13) O(3A)#1-Gd(1)-O(4A)#2 137.12(19) N(2)-C(11) 1.505(14) O(1)-Gd(1)-O(5) 77.27(19) O(7)-H(71) 0.89(10) O(2A)-Gd(1)-O(5) 73.7(2) O(1)-Gd(1)-O(2A) 84.33(19) O(3A)#1-Gd(1)-O(5) 75.84(19)
162 O(4A)#2-Gd(1)-O(5) 146.88(19) O(1B)#2-Gd(2)-O(6) 136.8(2) O(1)-Gd(1)-O(4B)#3 82.00(18) O(2)-Gd(2)-O(6) 74.2(2) O(2A)-Gd(1)-O(4B)#3 144.32(19) O(3)#5-Gd(2)-O(6) 70.9(2) O(3A)#1-Gd(1)-O(4B)#3 70.67(18) O(2B)#6-Gd(2)-O(6) 74.78(19) O(4A)#2-Gd(1)-O(4B)#3 73.98(19) O(4)#4-Gd(2)-O(7) 75.1(2) O(5)-Gd(1)-O(4B)#3 133.83(18) O(1A)-Gd(2)-O(7) 67.72(19) O(1)-Gd(1)-O(3B) 151.90(18) O(1B)#2-Gd(2)-O(7) 72.5(2) O(2A)-Gd(1)-O(3B) 74.19(19) O(2)-Gd(2)-O(7) 71.1(2) O(3A)#1-Gd(1)-O(3B) 83.61(19) O(3)#5-Gd(2)-O(7) 139.2(2) O(4A)#2-Gd(1)-O(3B) 98.4(2) O(2B)#6-Gd(2)-O(7) 140.04(19) O(5)-Gd(1)-O(3B) 79.44(19) O(6)-Gd(2)-O(7) 119.8(2) O(4B)#3-Gd(1)-O(3B) 125.86(17) O(1)-Gd(1)-O(4B) 155.55(17) O(2A)-Gd(1)-O(4B) 108.65(18) O(3A)#1-Gd(1)-O(4B) 76.09(18) O(4A)#2-Gd(1)-O(4B) 72.18(18) O(5)-Gd(1)-O(4B) 125.70(18) O(4B)#3-Gd(1)-O(4B) 75.49(17) O(3B)-Gd(1)-O(4B) 51.99(16) O(4)#4-Gd(2)-O(1A) 140.21(19) O(4)#4-Gd(2)-O(1B)#2 77.34(19) O(1A)-Gd(2)-O(1B)#2 78.41(19) O(4)#4-Gd(2)-O(2) 81.8(2) O(1A)-Gd(2)-O(2) 98.7(2) O(1B)#2-Gd(2)-O(2) 141.5(2) O(4)#4-Gd(2)-O(3)#5 121.1(2) O(1A)-Gd(2)-O(3)#5 81.80(19) O(1B)#2-Gd(2)-O(3)#5 75.38(19) O(2)-Gd(2)-O(3)#5 142.8(2) O(4)#4-Gd(2)-O(2B)#6 74.74(19) O(1A)-Gd(2)-O(2B)#6 144.78(18) O(1B)#2-Gd(2)-O(2B)#6 124.56(18) O(2)-Gd(2)-O(2B)#6 79.18(19) O(3)#5-Gd(2)-O(2B)#6 79.71(18) O(4)#4-Gd(2)-O(6) 144.1(2) O(1A)-Gd(2)-O(6) 70.91(19)
163 Table A2-3. Hydrogen coordinates ( x 104) and isotropic displacement parameters
(Å2x 103) for Gd2(C6H2O4S)3(OCHNMe2)2(H2O) ______x y z U(eq) ______H(3A) 2063 2620 2204 39 H(4A) 2746 1476 3387 38 H(3AA) 3239 1721 -1827 38 H(4AA) 2659 787 -3119 36 H(3BA) 5876 3763 -3255 32 H(4BA) 5815 4581 -1979 32 H(7A) 3817 882 -295 63 H(8A) 3741 477 1593 116 H(8B) 3629 -993 1528 116 H(8C) 2883 -99 1243 116 H(9A) 3615 -1227 -445 121 H(9B) 2895 -1557 -79 121 H(9C) 3769 -1991 353 121 H(10A) 1330 1193 596 54 H(11A) 1849 236 -1112 136 H(11B) 914 398 -1418 136 H(11C) 1287 -951 -1216 136 H(12A) 1148 -891 694 127 H(12B) 1444 -1724 78 127 H(12C) 542 -1298 -105 127 H(71) 2500(60) 5520(90) 250(60) 44 ______
164 Table A2-4: Hydrogen bonds for Gd2(C6H2O4S)3(OCHNMe2)2(H2O) ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(7)-H(71)...O(1) 0.89(10) 2.29(10) 3.172(9) 175(9) O(7)-H(71)...O(2) 0.89(10) 2.30(10) 2.915(9) 126(8) ______
Figure A2-1: The perspective drawing of Gd2(C6H2O4S)3(OCHNMe2)2(H2O) with non- hydrogen atoms represented by thermal ellipsoids drawn to encompass 50% of the electron density
165
(a)
(b)
Figure A2-2: Perspective drawings of Gd2(C6H2O4S)3(OCHNMe2)2(H2O) down the (a) b- axis of the unit cell and (b) the a-axis of the unit cell.
166
APPENDIX A3: CRYSTAL STRUCTURE TABLES AND FIGURES FOR . COMPOUND (3) [Eu4(C6H2O4S)6(H2O)2(DMF)3 (H2O/n-prOH)]
Wake Forest University X-Ray Code: a20n
. Table A4-1 Crystal Data and Structure refinement for Eu4(C6H2O4S)6(H2O)2(DMF)3 (H2O/n-prOH)
Empirical formula C46.50 H42 Eu4 N3 O30 S6 Formula weight 1923.03 Temperature 173(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group Pc (No. 7) Unit cell dimensions a = 17.801(3) Å b = 10.8402(15) Å, β = 90.140(2)° c = 16.749(2) Å Volume 3232.1(8) Å3 Z 2 Density (calculated) 1.976 g/cm3 Absorption coefficient 4.108 mm-1 F(000) 1860 Theta range for data collection 3.82 to 26.00° Index ranges -21≤h≤21, -13≤k≤13, -20≤l≤20 Reflections collected 26925 Independent reflections 12253 [R(int) = 0.0567] Completeness to theta = 26.00° 99.7 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.8209 and 0.6699 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 12253 / 401 / 521 Goodness-of-fit on F2 1.057
Final R indices [I>2sigma(I)] R1 = 0.0512, wR2 = 0.0998
R indices (all data) R1 = 0.0604, wR2 = 0.1041 Largest diff. peak and hole 2.673 and -1.716 e-/Å3 ______
167 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters
(Å2x 103) for Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n-prOH). U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ______x y z U(eq) ______Eu(1) 6405(1) 6049(1) -1623(1) 11(1) Eu(2) 6420(1) 4074(1) -3786(1) 11(1) Eu(3) 1354(1) 1443(1) -264(1) 12(1) Eu(4) 1432(1) -355(1) 1880(1) 15(1) S(1) -1072(2) 3253(4) 1030(3) 18(1) O(11) -2882(6) 4032(11) 2213(6) 17(3) O(12) -2533(7) 4582(11) 1002(6) 19(3) O(13) 648(6) 1381(12) 1781(7) 21(3) O(14) 394(6) 2160(10) 554(6) 16(3) C(11) -1712(7) 3315(15) 1777(8) 29(4) C(12) -1498(8) 2662(14) 2426(8) 24(4) C(13) -772(8) 2099(15) 2319(8) 28(4) C(14) -485(6) 2384(13) 1594(7) 12(3) C(15) -2419(7) 4040(14) 1652(8) 10(4) C(16) 250(6) 1955(14) 1278(7) 11(3) S(2) -1041(2) -1578(4) -562(3) 22(1) O(21) 734(6) -484(10) 638(6) 18(3) O(22) 383(5) -96(11) -597(6) 14(2) O(23) -2802(6) -3029(11) 347(7) 20(3) O(24) -2465(6) -3315(12) -917(6) 20(3) C(21) -361(7) -1504(13) 157(8) 16(3) C(22) -516(7) -2227(13) 793(8) 20(4) C(23) -1214(7) -2874(14) 689(8) 21(4) C(24) -1550(6) -2606(13) -4(8) 20(4) C(25) 295(8) -626(16) 60(8) 21(5) C(26) -2328(6) -3007(16) -204(8) 12(4) S(3) 3806(2) -2253(5) 420(3) 24(1) O(31) 5313(7) -3507(12) 464(7) 23(3) O(32) 5665(5) -2861(10) -738(6) 13(3) O(33) 2366(6) -1052(10) 867(6) 19(3)
168 O(34) 2079(6) -373(10) -362(7) 25(3) C(31) 4458(6) -2353(12) -321(7) 11(3) C(32) 4221(7) -1806(15) -1011(8) 26(4) C(33) 3496(7) -1247(14) -922(8) 22(4) C(34) 3221(6) -1408(13) -184(8) 21(3) C(35) 5206(7) -2953(17) -180(8) 17(4) C(36) 2497(7) -918(16) 135(8) 18(4) S(4) 3989(2) 2246(4) 1983(3) 25(1) O(41) 5491(7) 3238(10) 2388(6) 16(3) O(42) 5725(6) 4055(9) 1185(7) 13(3) O(43) 2531(7) 964(11) 2045(7) 26(4) O(44) 2100(6) 1543(12) 857(7) 26(3) C(41) 4558(7) 3117(15) 1396(8) 21(4) C(42) 4241(8) 3400(16) 686(9) 26(4) C(43) 3529(8) 2797(16) 591(9) 32(5) C(44) 3324(6) 2176(14) 1243(8) 18(4) C(45) 5321(7) 3505(14) 1687(7) 9(3) C(46) 2599(7) 1536(14) 1392(8) 11(4) S(5) 3882(2) 3350(4) -1440(3) 19(1) O(51) 2438(6) 2044(11) -1005(7) 18(3) O(52) 2234(7) 1244(13) -2195(8) 30(4) O(53) 5324(7) 4666(11) -1388(6) 19(3) O(54) 5736(6) 4134(10) -2603(7) 15(3) C(51) 3396(6) 2235(13) -1971(8) 13(3) C(52) 3771(8) 1820(13) -2618(8) 19(4) C(53) 4482(8) 2414(13) -2688(9) 24(4) C(54) 4590(6) 3292(12) -2127(7) 6(3) C(55) 2622(7) 1824(15) -1707(8) 17(4) C(56) 5275(8) 4066(15) -2030(8) 19(4) S(6) -1226(2) 2220(5) -2375(3) 26(1) O(61) 774(5) 2027(11) -1433(7) 20(3) O(62) 293(7) 1035(12) -2482(7) 23(3) O(63) -2912(6) 4175(11) -1579(7) 19(3) O(64) -2683(6) 3363(11) -2798(6) 22(3) C(61) -501(6) 2326(14) -1712(7) 13(4) C(62) -674(9) 3008(17) -1061(9) 38(5)
169 C(63) -1427(9) 3463(19) -1103(10) 42(6) C(64) -1768(7) 3168(14) -1789(8) 16(4) C(65) 247(7) 1748(16) -1900(10) 25(5) C(66) -2525(7) 3582(16) -2076(8) 16(4) O(1) 6641(7) 8195(12) -1855(7) 29(3) N(1) 6440(14) 10216(15) -1514(9) 46(4) C(1) 6288(18) 9110(20) -1769(12) 55(7) C(2) 5990(15) 11230(30) -1414(18) 77(8) C(3) 7186(15) 10370(30) -1275(17) 88(10) O(2) 6179(6) 1874(11) -3626(7) 26(3) N(2) 6384(15) -110(15) -3829(9) 53(4) C(4) 6617(9) 1001(16) -3676(10) 21(4) C(5) 6969(13) -1060(20) -3832(16) 63(7) C(6) 5650(20) -310(40) -3980(30) 144(17) O(3) 1225(7) -2555(11) 1682(7) 34(3) N(3) 1602(14) -4590(20) 1776(13) 79(8) C(7) 1756(14) -3310(20) 1653(13) 60(7) C(8) 760(30) -5000(60) 1950(30) 200(30) C(9) 2215(18) -5410(30) 1690(20) 108(12) O(4) d 1486(11) 3694(9) -190(11) 47(3) C(17) d 1139(15) 4420(20) -491(18) 14(7) C(18) d 1523(18) 5610(20) -652(16) 18(7) C(19) d 2100(40) 6050(70) -100(40) 150(30) O(5) 6410(8) 4855(7) -163(6) 21(2) O(6) 1360(9) 811(8) 3104(6) 23(2)
170 Table 3. Bond lengths [Å] and angles [°] for Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n- prOH) ______Eu(1)-O(32)#1 2.311(10) Eu(2)-O(23)#6 2.306(10) Eu(1)-O(11)#2 2.330(10) Eu(2)-O(54) 2.331(10) Eu(1)-O(63)#3 2.368(11) Eu(2)-O(42)#5 2.377(10) Eu(1)-O(1) 2.396(13) Eu(2)-O(12)#2 2.393(11) Eu(1)-O(24)#4 2.431(10) Eu(2)-O(31)#7 2.414(11) Eu(1)-O(41)#5 2.444(10) Eu(2)-O(64)#3 2.422(11) Eu(1)-O(53) 2.472(12) Eu(2)-O(2) 2.438(12) Eu(1)-O(5) 2.767(10) Eu(2)-O(5)#5 2.581(9) Eu(1)-O(54) 2.900(11) Eu(2)-O(11)#2 2.924(11) Eu(1)-Eu(2) 4.2091(9) Eu(3)-Eu(4) 4.0889(11) Eu(3)-O(44) 2.300(11) Eu(4)-O(52)#8 2.315(11) Eu(3)-O(61) 2.300(11) Eu(4)-O(13) 2.349(11) Eu(3)-O(14) 2.327(10) Eu(4)-O(6) 2.412(10) Eu(3)-O(34) 2.359(10) Eu(4)-O(62)#8 2.410(12) Eu(3)-O(51) 2.387(10) Eu(4)-O(21) 2.425(10) Eu(3)-O(22) 2.465(11) Eu(4)-O(3) 2.436(12) Eu(3)-O(4) 2.455(10) Eu(4)-O(43) 2.439(11) Eu(3)-O(21) 2.805(11) Eu(4)-O(33) 2.496(10) Eu(4)-O(44) 2.933(13) O(21)-C(25) 1.252(13) S(1)-C(14) 1.694(11) O(22)-C(25) 1.252(13) S(1)-C(11) 1.695(11) O(23)-C(26) 1.253(13) O(11)-C(15) 1.252(12) O(23)-Eu(2)#10 2.306(10) O(11)-Eu(1)#9 2.330(10) O(24)-C(26) 1.263(13) O(11)-Eu(2)#9 2.924(11) O(24)-Eu(1)#11 2.431(10) O(12)-C(15) 1.253(12) C(21)-C(22) 1.351(13) O(12)-Eu(2)#9 2.393(11) C(21)-C(25) 1.515(13) O(13)-C(16) 1.263(12) C(22)-C(23) 1.438(13) O(14)-C(16) 1.259(12) C(23)-C(24) 1.338(14) C(11)-C(12) 1.351(14) O(21)-C(25) 1.252(13) C(11)-C(15) 1.499(13) O(22)-C(25) 1.252(13) C(12)-C(13) 1.441(13) O(23)-C(26) 1.253(13) S(2)-C(21) 1.708(11) O(23)-Eu(2)#10 2.306(10) S(2)-C(24) 1.714(11) O(24)-C(26) 1.263(13)
171 O(24)-Eu(1)#11 2.431(10) C(22)-C(23) 1.438(13) C(21)-C(22) 1.351(13) C(23)-C(24) 1.338(14) C(21)-C(25) 1.515(13) O(32)#1-Eu(1)-O(11)#2 150.3(4) O(41)#5-Eu(1)-O(54) 64.6(3) O(32)#1-Eu(1)-O(63)#3 135.4(4) O(53)-Eu(1)-O(54) 48.5(3) O(11)#2-Eu(1)-O(63)#3 73.3(4) O(5)-Eu(1)-O(54) 99.5(3) O(32)#1-Eu(1)-O(1) 73.0(4) O(32)#1-Eu(1)-Eu(2) 144.8(3) O(11)#2-Eu(1)-O(1) 78.8(4) O(11)#2-Eu(1)-Eu(2) 41.9(3) O(63)#3-Eu(1)-O(1) 138.4(4) O(63)#3-Eu(1)-Eu(2) 65.5(3) O(32)#1-Eu(1)-O(24)#4 90.9(4) O(1)-Eu(1)-Eu(2) 110.6(3) O(11)#2-Eu(1)-O(24)#4 88.1(4) O(24)#4-Eu(1)-Eu(2) 123.8(2) O(63)#3-Eu(1)-O(24)#4 78.7(4) O(41)#5-Eu(1)-Eu(2) 65.3(3) O(1)-Eu(1)-O(24)#4 70.0(4) O(53)-Eu(1)-Eu(2) 80.5(2) O(32)#1-Eu(1)-O(41)#5 83.9(4) O(5)-Eu(1)-Eu(2) 121.55(15) O(11)#2-Eu(1)-O(41)#5 78.9(4) O(54)-Eu(1)-Eu(2) 32.0(2) O(63)#3-Eu(1)-O(41)#5 129.3(4) O(23)#6-Eu(2)-O(54) 149.9(4) O(1)-Eu(1)-O(41)#5 72.5(4) O(23)#6-Eu(2)-O(42)#5 136.1(4) O(24)#4-Eu(1)-O(41)#5 142.0(4) O(54)-Eu(2)-O(42)#5 73.7(4) O(32)#1-Eu(1)-O(53) 76.3(4) O(23)#6-Eu(2)-O(12)#2 74.7(4) O(11)#2-Eu(1)-O(53) 122.4(4) O(54)-Eu(2)-O(12)#2 121.2(4) O(63)#3-Eu(1)-O(53) 82.8(4) O(42)#5-Eu(2)-O(12)#2 83.3(4) O(1)-Eu(1)-O(53) 138.7(4) O(23)#6-Eu(2)-O(31)#7 92.2(5) O(24)#4-Eu(1)-O(53) 137.6(4) O(54)-Eu(2)-O(31)#7 91.3(4) O(41)#5-Eu(1)-O(53) 77.4(4) O(42)#5-Eu(2)-O(31)#7 77.5(4) O(32)#1-Eu(1)-O(5) 70.9(3) O(12)#2-Eu(2)-O(31)#7 135.5(4) O(11)#2-Eu(1)-O(5) 136.2(4) O(23)#6-Eu(2)-O(64)#3 83.0(4) O(63)#3-Eu(1)-O(5) 64.6(4) O(54)-Eu(2)-O(64)#3 76.9(4) O(1)-Eu(1)-O(5) 126.7(3) O(42)#5-Eu(2)-O(64)#3 128.9(4) O(24)#4-Eu(1)-O(5) 72.7(4) O(12)#2-Eu(2)-O(64)#3 77.4(4) O(41)#5-Eu(1)-O(5) 138.4(4) O(31)#7-Eu(2)-O(64)#3 144.1(4) O(53)-Eu(1)-O(5) 64.9(4) O(23)#6-Eu(2)-O(2) 72.3(4) O(32)#1-Eu(1)-O(54) 119.7(3) O(54)-Eu(2)-O(2) 80.9(4) O(11)#2-Eu(1)-O(54) 73.9(3) O(63)#3-Eu(1)-O(54) 67.3(4) O(1)-Eu(1)-O(54) 132.4(4) O(24)#4-Eu(1)-O(54) 144.8(4)
172 Table 7. Hydrogen bonds for Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n-prOH [Å and °]. ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(6)-H(6)...O(34)#8 0.847(10) 2.24(12) 2.906(17) 136(15) ______
Figure A3-1: A perspective drawing of the contents of the asymmetric unit for Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n-prOH) . Europium and sulfur atoms are represented by large cross-hatched or dotted spheres, oxygen and nitrogen atoms are represented by medium-sized shaded spheres and carbon and hydrogen atoms are represented by medium and small open spheres, respectively.
173
Figure A3-2: A perspective drawing of Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n-prOH with completed coordination spheres for each of the europium atoms. Europium and sulfur atoms are represented by 50% probability ellipsoids and the remaining atoms are represented as described in Figure A3-1. Hydrogen atoms have been omitted from this view for purposes of clarity.
Figures A3-3: A projection of the unit cell when viewed down the c-axis in crystalline Eu4(C6H2O4S)6(OH2)2(DMF)3- (H2O/n-prOH) with atoms represented as in Figure A3-1. Hydrogen atoms have been omitted from these views for purposes of clarity.
174 APPENDIX A4: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (4) [Y(C6H2O4S)(NO3)(ONC3H7)2]
Wake Forest University X-Ray Code: a23m
Table A4-1 Crystal Data and Structure refinement for Y(C6H2O4S)(NO3)(ONC3H7)2 ______Identification code a77l2m Empirical formula C12 H16 N3 O9 S Y Formula weight 467.25 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/n Unit cell dimensions a = 10.607(4) Å b = 10.668(4) Å, β = 95.870(6)° c = 15.709(5) Å Volume 1768.3(10) Å3 Z 4 Density (calculated) 1.755 g/cm3 Absorption coefficient 3.468 mm-1 F(000) 944 Crystal size 0.12 x 0.07 x 0.05 mm3 Theta range for data collection 3.82 to 26.40° Index ranges -13≤h≤13, -13≤k≤12, -19≤l≤19 Independent reflections 3590 [R(int) = 0.0866] Completeness to theta = 26.40° 98.8 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.8457 and 0.6810 Refinement method Full-matrix least-squares on F2 Data / parameters 3590 / 307 Goodness-of-fit on F2 1.004 Final R indices [I>2sigma(I)] R1 = 0.0594, wR2 = 0.1039 R indices (all data) R1 = 0.0940, wR2 = 0.1121 Largest diff. peak and hole 0.487 and -0.649 e.Å-3 ______
175 Table A4-2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for Y(C6H2O4S)(NO3)(ONC3H7)2. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ______x y z U(eq) ______Y(1) 2509(1) 4678(1) 182(1) 19(1) S(1) 4393(2) 7332(2) 2504(1) 27(1) O(1) 4132(4) 5373(5) 1168(3) 38(1) O(2) 5915(4) 9661(5) 4228(3) 46(1) O(3) 3107(5) 6856(4) -176(3) 47(1) O(4) 1843(5) 6662(4) 787(3) 45(1) O(5) 2512(6) 8515(5) 475(4) 76(2) O(6) 1601(5) 2889(5) -554(4) 54(2) O(7) 3419(5) 2888(5) 814(3) 50(1) O(8) 6097(4) 5524(4) 794(3) 36(1) O(9) 3907(4) 9098(4) 3890(3) 32(1) N(1) 4520(14) 1337(14) 1468(12) 32(4) N(2) 528(15) 1098(14) -911(11) 43(4) N(3) 2481(6) 7376(6) 360(4) 51(2) C(1) 5223(6) 5798(6) 1246(4) 27(2) C(2) 5544(6) 6728(6) 1950(4) 32(2) C(3) 6709(7) 7189(8) 2225(5) 58(3) C(4) 6666(7) 8054(8) 2886(5) 53(2) C(5) 5460(6) 8224(6) 3109(4) 33(2) C(6) 5071(6) 9043(6) 3789(4) 24(1) C(7) 4256(8) 2216(8) 797(7) 73(3) C(8) 5732(13) 708(13) 1581(13) 65(6) C(9) 3490(40) 810(40) 1873(18) 35(6) C(9') 3850(50) 850(50) 1820(30) 90(20) C(10) 1187(14) 1938(15) -397(11) 46(4) C(11) 299(14) -127(12) -629(10) 51(5) C(12) 40(20) 1460(20) -1781(19) 77(11) N(1') 4350(19) 1017(18) 1013(10) 43(5) C(8') 5136(16) 2(14) 774(12) 58(6) N(2') 613(15) 1450(16) -1398(15) 32(4)
176 C(10') 825(13) 2539(15) -958(9) 30(4) C(11') 1589(17) 469(15) -1291(11) 59(5) C(12') -495(19) 1203(19) -1938(13) 34(5)
The nitrogen and carbon atoms of both DMF solvent molecules are disordered over two preferred orientations and were refined with corresponding occupancies of 52% and 48%, respectively.
Table A4-3. Bond lengths [Å] and angles [°] for Y(C6H2O4S)(NO3)(ONC3H7)2 ______Y(1)-O(8)#1 2.246(4) Y(1)-O(1) 2.318(4) Y(1)-O(2)#2 2.254(4) Y(1)-O(6) 2.383(5) Y(1)-O(9)#3 2.283(4) Y(1)-O(4) 2.453(4) Y(1)-O(7) 2.317(5) Y(1)-O(3) 2.488(5) S(1)-C(5) 1.694(6) S(1)-C(2) 1.697(6) O(1)-C(1) 1.237(7) O(8)-C(1) 1.259(7) O(2)-C(6) 1.259(7) O(9)-C(6) 1.262(7) O(3)-N(3) 1.254(7) O(6)-C(10') 1.055(14) O(4)-N(3) 1.256(7) O(6)-C(10) 1.142(16) O(5)-N(3) 1.229(7) O(7)-C(7) 1.144(8) N(1)-C(7) 1.417(18) N(2)-C(10) 1.35(2) N(1)-C(9) 1.43(4) N(2)-C(11) 1.408(19) N(1)-C(8) 1.445(19) N(2)-C(12) 1.46(3) C(1)-C(2) 1.499(8) C(4)-C(5) 1.372(9) C(2)-C(3) 1.359(8) C(5)-C(6) 1.472(8) C(3)-C(4) 1.393(9) C(7)-N(1') 1.32(2) N(2')-C(10') 1.36(2) C(9')-N(1') 1.44(4) N(2')-C(12') 1.40(2) N(1')-C(8') 1.44(2) N(2')-C(11') 1.47(2) O(8)#1-Y(1)-O(2)#2 94.45(16) O(9)#3-Y(1)-O(7) 77.02(17) O(8)#1-Y(1)-O(9)#3 158.72(16) O(8)#1-Y(1)-O(1) 89.50(15) O(2)#2-Y(1)-O(9)#3 90.67(16) O(2)#2-Y(1)-O(1) 143.07(17) O(8)#1-Y(1)-O(7) 86.52(17) O(9)#3-Y(1)-O(1) 98.74(15) O(2)#2-Y(1)-O(7) 142.58(18) O(7)-Y(1)-O(1) 74.26(17)
177 O(8)#1-Y(1)-O(6) 81.59(17) O(1)-Y(1)-O(4) 71.83(16) O(2)#2-Y(1)-O(6) 72.0(2) O(6)-Y(1)-O(4) 139.54(19) O(9)#3-Y(1)-O(6) 80.40(17) O(8)#1-Y(1)-O(3) 74.62(16) O(7)-Y(1)-O(6) 71.2(2) O(2)#2-Y(1)-O(3) 75.44(17) O(1)-Y(1)-O(6) 144.7(2) O(9)#3-Y(1)-O(3) 126.63(16) O(8)#1-Y(1)-O(4) 125.64(17) O(7)-Y(1)-O(3) 139.63(18) O(2)#2-Y(1)-O(4) 76.20(17) O(1)-Y(1)-O(3) 70.30(16) O(9)#3-Y(1)-O(4) 75.64(16) O(6)-Y(1)-O(3) 137.58(19) O(7)-Y(1)-O(4) 131.95(17) O(4)-Y(1)-O(3) 51.09(16) C(5)-S(1)-C(2) 91.5(3) C(1)-O(1)-Y(1) 143.8(4) C(10)-O(6)-Y(1) 138.8(10) C(6)-O(2)-Y(1)#4 166.1(5) C(7)-O(7)-Y(1) 142.8(6) N(3)-O(3)-Y(1) 95.5(4) C(1)-O(8)-Y(1)#1 169.0(4) N(3)-O(4)-Y(1) 97.2(4) C(6)-O(9)-Y(1)#5 144.0(4) C(10')-O(6)-Y(1) 145.8(11) C(7)-N(1)-C(9) 119(2) C(7)-N(1)-C(8) 120.3(15) C(9)-N(1)-C(8) 118(2) C(10)-N(2)-C(11) 121.6(15) C(10)-N(2)-C(12) 119.4(17) C(11)-N(2)-C(12) 119.0(15)
178
Figure A4-1: A view of the asymmetric unit of Y(C6H2O4S)(NO3)(ONC3H7)2 with nonhydrogen and hydrogen atoms represented by arbitrarily small spheres, which are in no way representative of their true thermal motion.
179
Figure A4-2: A view of the framework of Y(C6H2O4S)(NO3)(ONC3H7)2 projected down the a-axis with nonhydrogen atoms represented by arbitrarily small spheres, which are in no way representative of their true thermal motion. Hydrogen atoms omitted for clarity.
180
Figure A4-3: A view of the framework of Y(C6H2O4S)(NO3)(ONC3H7)2 projected down the b-axis with nonhydrogen atoms represented by arbitrarily small spheres, which are in no way representative of their true thermal motion. Hydrogen atoms omitted for clarity.
181 APPENDIX A5: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (5) [Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO)]
Wake Forest University X-Ray Code: a36o
Table A5-1 Crystal Data and Structure refinement for Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______Identification code a36o2m Empirical formula C48 H56 F12 N4 O18 Tb2 Formula weight 1522.81 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 6 Space group C2/c – C 2h (No. 15) Unit cell dimensions a = 23.282(3) Å b = 11.185(2) Å, β = 108.650(2)° c = 23.230(3) Å Volume 5731.6(13) Å3 Z 4 Density (calculated) 1.765 g/cm3 Absorption coefficient 2.559 mm-1 F(000) 3016 Crystal size 0.22 x 0.09 x 0.03 mm3 Theta range for data collection 3.96 to 30.05° Index ranges -32≤h≤32, -15≤k≤15, -32≤l≤30 Independent reflections 8299 [R(int) = 0.0594] Completeness to theta = 30.05° 98.6 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.4326 and 0.3213 Refinement method Full-matrix least-squares on F2 Data / parameters 8299 / 390 Goodness-of-fit on F2 1.048
Final R indices [6637 I>2σ(I)] R1 = 0.0412, wR2 = 0.0829
R indices (all data) R1 = 0.0576, wR2 = 0.0888 Largest diff. peak and hole 1.691 and -0.820 e-/Å3
______
182 Table A5-2. Bond lengths [Å] and angles [°] for Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - a,b 2(Et2NCHO) ______Tb(1)-O(1) 2.366(2) Tb(1)-O(6)#3 2.747(3) Tb(1)-O(2)#1 2.319(2) Tb(1)-O(6)#2 2.349(3) Tb(1)-O(3) 2.469(2) Tb(1)-O(7) 2.381(2) Tb(1)-O(4) 2.457(3) Tb(1)-O(8) 2.409(3) Tb(1)-O(5)#3 2.478(3) F(1)-C(3) 1.351(4) O(1)-C(1) 1.249(3) F(2)-C(4) 1.339(4) O(2)-C(6) 1.247(3) F(3)-C(9) 1.337(4) O(3)-C(7) 1.246(4) F(4)-C(10) 1.346(4) O(4)-C(7) 1.259(4) F(5)-C(12) 1.337(4) O(5)-C(14) 1.239(5) F(6)-C(13) 1.335(4) O(6)-C(14) 1.255(4) C(1)-C(2) 1.507(7) C(7)-C(8) 1.512(5) C(5)-C(6) 1.497(6) C(11)-C(14) 1.513(5) C(2)-C(3) 1.383(4) C(25)-C(26) 1.483(7) C(3)-C(4) 1.374(5) O(8)-C(20) 1.448(6) C(4)-C(5) 1.388(4) O(8)-H(8O) 0.87(5) C(8)-C(9) 1.400(5) C(20)-C(21) 1.460(8) C(8)-C(13) 1.387(5) O(2)#1-Tb(1)-O(6)#2 74.77(9) C(9)-C(10) 1.376(5) O(2)#1-Tb(1)-O(1) 131.17(9) C(10)-C(11) 1.374(5) O(6)#2-Tb(1)-O(1) 72.72(8) C(11)-C(12) 1.377(5) O(2)#1-Tb(1)-O(7) 139.38(9) C(12)-C(13) 1.390(5) O(6)#2-Tb(1)-O(7) 145.00(8) O(7)-C(15) 1.229(4) O(1)-Tb(1)-O(7) 75.65(9) O(9)-C(22) 1.224(5) O(2)#1-Tb(1)-O(8) 73.10(10) N(1)-C(15) 1.322(5) O(6)#2-Tb(1)-O(8) 137.93(9) N(2)-C(22) 1.335(6) O(1)-Tb(1)-O(8) 149.14(9) N(1)-C(16) 1.467(6) O(7)-Tb(1)-O(8) 73.90(10) N(1)-C(18) 1.482(5) O(2)#1-Tb(1)-O(4) 130.17(9) N(2)-C(25) 1.461(6) O(6)#2-Tb(1)-O(4) 86.13(9) N(2)-C(23) 1.466(6) O(1)-Tb(1)-O(4) 82.59(9) C(16)-C(17) 1.493(7) O(7)-Tb(1)-O(4) 75.21(9) C(18)-C(19) 1.508(7) O(8)-Tb(1)-O(4) 94.35(10) C(23)-C(24) 1.501(8) O(2)#1-Tb(1)-O(3) 77.54(9)
183 O(6)#2-Tb(1)-O(3) 74.24(9) O(4)-Tb(1)-O(5)#3 147.68(9) O(1)-Tb(1)-O(3) 125.39(9) O(3)-Tb(1)-O(5)#3 146.72(9) O(7)-Tb(1)-O(3) 114.06(9) O(2)#1-Tb(1)-O(6)#3 68.86(8) O(8)-Tb(1)-O(3) 72.89(9) O(6)#2-Tb(1)-O(6)#3 71.32(9) O(4)-Tb(1)-O(3) 52.89(9) O(1)-Tb(1)-O(6)#3 66.75(8) O(2)#1-Tb(1)-O(5)#3 78.25(9) O(7)-Tb(1)-O(6)#3 109.15(8) O(6)#2-Tb(1)-O(5)#3 120.29(9) O(8)-Tb(1)-O(6)#3 119.53(9) O(1)-Tb(1)-O(5)#3 87.83(9) O(4)-Tb(1)-O(6)#3 145.95(9) O(7)-Tb(1)-O(5)#3 72.51(9) O(3)-Tb(1)-O(6)#3 136.76(8) O(8)-Tb(1)-O(5)#3 78.45(10) O(5)#3-Tb(1)-O(6)#3 49.33(8) C(1)-O(1)-Tb(1) 138.6(3) C(14)-O(5)-Tb(1)#5 100.3(2) C(6)-O(2)-Tb(1)#4 139.2(3) C(14)-O(6)-Tb(1)#2 161.0(2) C(7)-O(3)-Tb(1) 92.3(2) C(14)-O(6)-Tb(1)#5 87.1(2) C(7)-O(4)-Tb(1) 92.5(2) Tb(1)#2-O(6)-Tb(1)#5 108.61(9) O(1)-C(1)-O(1)#6 128.4(5) C(13)-C(8)-C(9) 116.0(3) O(1)-C(1)-C(2) 115.8(2) C(13)-C(8)-C(7) 122.9(3) O(1)#6-C(1)-C(2) 115.8(2) C(9)-C(8)-C(7) 121.1(3) C(3)#6-C(2)-C(3) 116.5(5) F(3)-C(9)-C(10) 117.7(3) C(3)#6-C(2)-C(1) 121.8(2) F(3)-C(9)-C(8) 121.0(3) C(3)-C(2)-C(1) 121.8(2) C(10)-C(9)-C(8) 121.3(3) F(1)-C(3)-C(4) 117.6(3) F(4)-C(10)-C(11) 119.1(3) F(1)-C(3)-C(2) 120.3(3) F(4)-C(10)-C(9) 118.6(3) C(4)-C(3)-C(2) 122.0(3) C(11)-C(10)-C(9) 122.3(4) F(2)-C(4)-C(3) 118.7(3) C(10)-C(11)-C(12) 117.2(3) F(2)-C(4)-C(5) 119.8(3) C(10)-C(11)-C(14) 120.6(3) C(3)-C(4)-C(5) 121.5(3) C(12)-C(11)-C(14) 122.2(3) C(4)-C(5)-C(4)#6 116.6(4) F(5)-C(12)-C(11) 120.0(3) C(4)-C(5)-C(6) 121.7(2) F(5)-C(12)-C(13) 118.8(3) C(4)#6-C(5)-C(6) 121.7(2) C(11)-C(12)-C(13) 121.2(3) O(2)-C(6)-O(2)#6 128.6(5) F(6)-C(13)-C(8) 120.7(3) O(2)-C(6)-C(5) 115.7(2) F(6)-C(13)-C(12) 117.2(3) O(2)#6-C(6)-C(5) 115.7(2) C(8)-C(13)-C(12) 122.0(3) O(3)-C(7)-O(4) 122.3(3) O(5)-C(14)-O(6) 123.3(3) O(3)-C(7)-C(8) 118.1(3) O(5)-C(14)-C(11) 118.5(3) O(4)-C(7)-C(8) 119.6(3) O(6)-C(14)-C(11) 118.2(3)
184 Table A5-3. Torsion angles [°] for Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______O(2)#1-Tb(1)-O(1)-C(1) 22.5(3) O(6)#2-Tb(1)-O(1)-C(1) -27.9(2) O(7)-Tb(1)-O(1)-C(1) 167.3(3) O(8)-Tb(1)-O(1)-C(1) 157.8(2) O(4)-Tb(1)-O(1)-C(1) -116.1(3) O(3)-Tb(1)-O(1)-C(1) -83.1(3) O(5)#3-Tb(1)-O(1)-C(1) 94.8(3) O(6)#3-Tb(1)-O(1)-C(1) 48.7(2) O(2)#1-Tb(1)-O(3)-C(7) -174.3(2) O(6)#2-Tb(1)-O(3)-C(7) -96.9(2) O(1)-Tb(1)-O(3)-C(7) -42.2(3) O(7)-Tb(1)-O(3)-C(7) 46.9(2) O(8)-Tb(1)-O(3)-C(7) 109.8(2) O(4)-Tb(1)-O(3)-C(7) 0.4(2) O(5)#3-Tb(1)-O(3)-C(7) 141.5(2) O(6)#3-Tb(1)-O(3)-C(7) -135.0(2) C(14)#3-Tb(1)-O(3)-C(7) -172.0(2) O(2)#1-Tb(1)-O(4)-C(7) 6.5(3) O(6)#2-Tb(1)-O(4)-C(7) 72.8(2) O(1)-Tb(1)-O(4)-C(7) 145.8(2) O(7)-Tb(1)-O(4)-C(7) -137.1(2) O(8)-Tb(1)-O(4)-C(7) -65.0(2) O(3)-Tb(1)-O(4)-C(7) -0.4(2) O(5)#3-Tb(1)-O(4)-C(7) -140.2(2) O(6)#3-Tb(1)-O(4)-C(7) 120.4(2) Tb(1)-O(1)-C(1)-O(1)#6 -10.25(18) Tb(1)-O(1)-C(1)-C(2) 169.75(18) O(1)-C(1)-C(2)-C(3)#6 48.0(2) O(1)#6-C(1)-C(2)-C(3)#6 -132.0(2) O(1)-C(1)-C(2)-C(3) -132.0(2) O(1)#6-C(1)-C(2)-C(3) 48.0(2) C(3)#6-C(2)-C(3)-F(1) -176.7(4) C(1)-C(2)-C(3)-F(1) 3.2(4) C(3)#6-C(2)-C(3)-C(4) -0.2(2)
185 C(1)-C(2)-C(3)-C(4) 179.8(2) F(1)-C(3)-C(4)-F(2) -0.3(5) C(2)-C(3)-C(4)-F(2) -176.9(3) F(1)-C(3)-C(4)-C(5) 177.1(3) C(2)-C(3)-C(4)-C(5) 0.5(5) F(2)-C(4)-C(5)-C(4)#6 177.1(4) C(3)-C(4)-C(5)-C(4)#6 -0.2(2) F(2)-C(4)-C(5)-C(6) -2.9(4) C(3)-C(4)-C(5)-C(6) 179.8(2) Tb(1)#4-O(2)-C(6)-O(2)#6 9.45(18) Tb(1)#4-O(2)-C(6)-C(5) -170.54(18) C(4)-C(5)-C(6)-O(2) 130.9(2) C(4)#6-C(5)-C(6)-O(2) -49.1(2) C(4)-C(5)-C(6)-O(2)#6 -49.1(2) C(4)#6-C(5)-C(6)-O(2)#6 130.9(2) Tb(1)-O(3)-C(7)-O(4) -0.7(4) Tb(1)-O(3)-C(7)-C(8) 179.5(3) Tb(1)-O(4)-C(7)-O(3) 0.7(4) Tb(1)-O(4)-C(7)-C(8) -179.5(3) O(3)-C(7)-C(8)-C(13) -150.4(4) O(4)-C(7)-C(8)-C(13) 29.7(6) O(3)-C(7)-C(8)-C(9) 28.5(5) O(4)-C(7)-C(8)-C(9) -151.3(4) C(13)-C(8)-C(9)-F(3) -179.9(4) C(7)-C(8)-C(9)-F(3) 1.1(6) C(13)-C(8)-C(9)-C(10) 0.6(6) C(7)-C(8)-C(9)-C(10) -178.4(4) F(3)-C(9)-C(10)-F(4) 1.1(6) C(8)-C(9)-C(10)-F(4) -179.4(4) F(3)-C(9)-C(10)-C(11) -179.2(4) C(8)-C(9)-C(10)-C(11) 0.3(6) ______
186 Table A5-4. Hydrogen bonds for Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) [Å and °] ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(8)-H(8O)...O(9) 0.87(5) 1.87(5) 2.699(4) 159(4) ______
Figure A5-1: shows a perspective drawing of the contents of the asymmetric unit for Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). Nonhydrogen atoms are represented by thermal vibration ellipsoids drawn to encompass 50% of their electron density. Hydrogen atoms are represented by arbitrarily-small spheres, which are in no way representative of their true thermal motion.
187
Figure A5-2: Perspective view of projections down the a-axis of the unit cell in crystalline Tb2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) Hydrogen atoms have been omitted for clarity.
188 APPENDIX A6: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (6) [Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO)]
Wake Forest University X-Ray Code: a42o
Table A6-1 Crystal Data and Structure refinement for Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______Identification code a42o2m Empirical formula C48 H56 F12 N4 O18 Gd2 Formula weight 1519.47 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 6 Space group C2/c – C 2h (No. 15) Unit cell dimensions a = 23.312(3) Å b = 11.2196(15) Å, β = 108.630(2)° c = 23.249(3) Å Volume 5762.2(14) Å3 Z 4 Density (calculated) 1.752 g/cm3 Absorption coefficient 2.393 mm-1 F(000) 3008 Crystal size 0.18 x 0.04 x 0.02 mm3 Theta range for data collection 3.96 to 28.50° Index ranges -31≤h≤31, -14≤k≤15, -31≤l≤31 Independent reflections 7269 [R(int) = 0.0577] Completeness to theta = 57.00° 99.4 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.4326 and 0.3526 Refinement method Full-matrix least-squares on F2 Data / parameters 7269 / 390 Goodness-of-fit on F2 1.145
Final R indices [6196 I>2σ(I)] R1 = 0.0472, wR2 = 0.0930
R indices (all data) R1 = 0.0591, wR2 = 0.0971 Largest diff. peak and hole 1.678 and -2.168 e-/Å3 ______
189 Table A6-2. Bond lengths [Å] and angles [°] for Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - a,b 2(Et2NCHO) ______Gd(1)-O(2)#1 2.333(3) Gd(1)-O(4) 2.470(3) Gd(1)-O(6)#2 2.370(3) Gd(1)-O(3) 2.489(3) Gd(1)-O(1) 2.380(3) Gd(1)-O(5)#3 2.490(3) Gd(1)-O(7) 2.401(3) Gd(1)-O(6)#3 2.726(3) Gd(1)-O(8) 2.426(3) F(1)-C(3) 1.337(5) O(1)-C(1) 1.248(4) F(2)-C(4) 1.338(5) O(2)-C(6) 1.249(4) F(3)-C(9) 1.343(5) O(3)-C(7) 1.248(5) F(4)-C(10) 1.341(5) O(4)-C(7) 1.248(5) F(5)-C(12) 1.338(5) O(5)-C(14) 1.235(6) F(6)-C(13) 1.342(5) O(6)-C(14) 1.252(5) C(1)-C(2) 1.517(8) C(7)-C(8) 1.506(6) C(5)-C(6) 1.506(8) C(11)-C(14) 1.518(6) C(2)-C(3) 1.387(5) N(2)-C(22) 1.342(7) C(3)-C(4) 1.384(6) N(1)-C(16) 1.467(6) C(4)-C(5) 1.376(5) N(1)-C(18) 1.482(5) C(8)-C(13) 1.373(6) N(2)-C(25) 1.461(6) C(8)-C(9) 1.406(6) N(2)-C(23) 1.466(6) C(9)-C(10) 1.366(6) C(16)-C(17) 1.495(10) C(10)-C(11) 1.378(6) C(18)-C(19) 1.494(10) C(11)-C(12) 1.381(6) C(23)-C(24) 1.490(10) C(12)-C(13) 1.386(6) C(25)-C(26) 1.481(9) O(7)-C(15) 1.234(5) O(8)-C(20) 1.450(8) O(9)-C(22) 1.235(7) O(8)-H(8O) 0.79(6) N(1)-C(15) 1.320(6) C(20)-C(21) 1.455(10) O(2)#1-Gd(1)-O(6)#2 74.83(11) O(1)-Gd(1)-O(8) 149.10(12) O(2)#1-Gd(1)-O(1) 131.78(10) O(7)-Gd(1)-O(8) 73.66(12) O(6)#2-Gd(1)-O(1) 72.57(10) O(2)#1-Gd(1)-O(4) 129.80(11) O(2)#1-Gd(1)-O(7) 139.13(11) O(6)#2-Gd(1)-O(4) 86.66(11) O(6)#2-Gd(1)-O(7) 145.17(10) O(1)-Gd(1)-O(4) 82.50(11) O(1)-Gd(1)-O(7) 75.70(11) O(7)-Gd(1)-O(4) 75.24(11) O(2)#1-Gd(1)-O(8) 73.15(12) O(8)-Gd(1)-O(4) 93.48(13) O(6)#2-Gd(1)-O(8) 138.02(11) O(2)#1-Gd(1)-O(3) 77.49(11)
190 O(6)#2-Gd(1)-O(3) 74.23(11) O(4)-Gd(1)-O(5)#3 147.59(12) O(1)-Gd(1)-O(3) 124.64(11) O(3)-Gd(1)-O(5)#3 146.74(11) O(7)-Gd(1)-O(3) 114.16(11) O(2)#1-Gd(1)-O(6)#3 69.33(9) O(8)-Gd(1)-O(3) 72.91(12) O(6)#2-Gd(1)-O(6)#3 71.36(11) O(4)-Gd(1)-O(3) 52.47(11) O(1)-Gd(1)-O(6)#3 67.12(10) O(2)#1-Gd(1)-O(5)#3 78.25(11) O(7)-Gd(1)-O(6)#3 108.78(10) O(6)#2-Gd(1)-O(5)#3 120.24(11) O(8)-Gd(1)-O(6)#3 119.86(11) O(1)-Gd(1)-O(5)#3 88.57(11) O(4)-Gd(1)-O(6)#3 146.46(11) O(7)-Gd(1)-O(5)#3 72.36(11) O(3)-Gd(1)-O(6)#3 137.04(10) O(8)-Gd(1)-O(5)#3 78.51(12) O(5)#3-Gd(1)-O(6)#3 49.29(10) C(1)-O(1)-Gd(1) 137.9(3) C(14)-O(5)-Gd(1)#5 99.7(3) C(6)-O(2)-Gd(1)#4 139.2(3) C(14)-O(6)-Gd(1)#2 159.8(3) C(7)-O(3)-Gd(1) 91.9(3) C(14)-O(6)-Gd(1)#5 88.0(3) C(7)-O(4)-Gd(1) 92.7(3) Gd(1)#2-O(6)-Gd(1)#5 108.57(11) O(1)#6-C(1)-O(1) 129.5(5) C(13)-C(8)-C(9) 115.2(4) O(1)#6-C(1)-C(2) 115.3(3) C(13)-C(8)-C(7) 123.5(4) O(1)-C(1)-C(2) 115.3(3) C(9)-C(8)-C(7) 121.3(4) C(3)#6-C(2)-C(3) 117.1(5) F(3)-C(9)-C(10) 117.0(4) C(3)#6-C(2)-C(1) 121.5(3) F(3)-C(9)-C(8) 120.8(4) C(3)-C(2)-C(1) 121.5(3) C(10)-C(9)-C(8) 122.2(4) F(1)-C(3)-C(4) 118.3(4) F(4)-C(10)-C(9) 119.3(4) F(1)-C(3)-C(2) 120.3(4) F(4)-C(10)-C(11) 119.2(4) C(4)-C(3)-C(2) 121.3(4) C(9)-C(10)-C(11) 121.6(4) F(2)-C(4)-C(5) 120.8(4) C(10)-C(11)-C(12) 117.4(4) F(2)-C(4)-C(3) 118.0(4) C(10)-C(11)-C(14) 120.7(4) C(5)-C(4)-C(3) 121.1(4) C(12)-C(11)-C(14) 122.0(4) C(4)-C(5)-C(4)#6 118.0(6) F(5)-C(12)-C(11) 119.8(4) C(4)-C(5)-C(6) 121.0(3) F(5)-C(12)-C(13) 119.5(4) C(4)#6-C(5)-C(6) 121.0(3) C(11)-C(12)-C(13) 120.7(4) O(2)#6-C(6)-O(2) 128.3(6) F(6)-C(13)-C(8) 120.6(4) O(2)#6-C(6)-C(5) 115.9(3) F(6)-C(13)-C(12) 116.4(4) O(2)-C(6)-C(5) 115.9(3) C(8)-C(13)-C(12) 123.0(4) O(3)-C(7)-O(4) 122.9(4) O(5)-C(14)-O(6) 123.0(4) O(3)-C(7)-C(8) 117.6(4) O(5)-C(14)-C(11) 118.9(4) O(4)-C(7)-C(8) 119.5(4) O(6)-C(14)-C(11) 118.0(4)
191 192 Table A6-3. Torsion angles [°] for Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______O(2)#1-Gd(1)-O(1)-C(1) 20.9(4) O(6)#2-Gd(1)-O(1)-C(1) -28.7(3) O(7)-Gd(1)-O(1)-C(1) 165.8(3) O(8)-Gd(1)-O(1)-C(1) 158.2(3) O(4)-Gd(1)-O(1)-C(1) -117.6(3) O(3)-Gd(1)-O(1)-C(1) -84.5(3) O(5)#3-Gd(1)-O(1)-C(1) 93.7(3) O(6)#3-Gd(1)-O(1)-C(1) 47.9(3) O(2)#1-Gd(1)-O(3)-C(7) -175.6(3) O(6)#2-Gd(1)-O(3)-C(7) -98.0(3) O(1)-Gd(1)-O(3)-C(7) -43.0(3) O(7)-Gd(1)-O(3)-C(7) 45.9(3) O(8)-Gd(1)-O(3)-C(7) 108.5(3) O(4)-Gd(1)-O(3)-C(7) 0.0(3) O(5)#3-Gd(1)-O(3)-C(7) 140.4(3) O(6)#3-Gd(1)-O(3)-C(7) -135.8(3) O(2)#1-Gd(1)-O(4)-C(7) 5.5(4) O(6)#2-Gd(1)-O(4)-C(7) 72.6(3) O(1)-Gd(1)-O(4)-C(7) 145.4(3) O(7)-Gd(1)-O(4)-C(7) -137.4(3) O(8)-Gd(1)-O(4)-C(7) -65.3(3) O(3)-Gd(1)-O(4)-C(7) 0.0(3) O(5)#3-Gd(1)-O(4)-C(7) -139.3(3) O(6)#3-Gd(1)-O(4)-C(7) 120.7(3) Gd(1)-O(1)-C(1)-O(1)#6 -9.3(2) Gd(1)-O(1)-C(1)-C(2) 170.7(2) O(1)#6-C(1)-C(2)-C(3)#6 -131.2(3) O(1)-C(1)-C(2)-C(3)#6 48.8(3) O(1)#6-C(1)-C(2)-C(3) 48.8(3) O(1)-C(1)-C(2)-C(3) -131.2(3) C(3)#6-C(2)-C(3)-F(1) -177.5(5) C(1)-C(2)-C(3)-F(1) 2.5(5) C(3)#6-C(2)-C(3)-C(4) 0.4(3) C(1)-C(2)-C(3)-C(4) -179.6(3)
193 F(1)-C(3)-C(4)-F(2) 0.7(6) C(2)-C(3)-C(4)-F(2) -177.2(3) F(1)-C(3)-C(4)-C(5) 177.1(3) C(2)-C(3)-C(4)-C(5) -0.8(6) F(2)-C(4)-C(5)-C(4)#6 176.7(5) C(3)-C(4)-C(5)-C(4)#6 0.4(3) F(2)-C(4)-C(5)-C(6) -3.3(5) C(3)-C(4)-C(5)-C(6) -179.6(3) Gd(1)#4-O(2)-C(6)-O(2)#6 9.0(2) Gd(1)#4-O(2)-C(6)-C(5) -171.0(2) C(4)-C(5)-C(6)-O(2)#6 -49.0(3) C(4)#6-C(5)-C(6)-O(2)#6 131.0(3) C(4)-C(5)-C(6)-O(2) 131.0(3) C(4)#6-C(5)-C(6)-O(2) -49.0(3) Gd(1)-O(3)-C(7)-O(4) -0.1(5) Gd(1)-O(3)-C(7)-C(8) 179.2(4) Gd(1)-O(4)-C(7)-O(3) 0.1(5) Gd(1)-O(4)-C(7)-C(8) -179.2(4) O(2)#1-Gd(1)-C(7)-O(3) 4.5(3) O(6)#2-Gd(1)-C(7)-O(3) 75.8(3) O(1)-Gd(1)-C(7)-O(3) 144.6(3) O(7)-Gd(1)-C(7)-O(3) -138.9(3) O(8)-Gd(1)-C(7)-O(3) -66.1(3) O(4)-Gd(1)-C(7)-O(3) -179.9(5) O(5)#3-Gd(1)-C(7)-O(3) -88.5(4) O(6)#3-Gd(1)-C(7)-O(3) 76.4(4) O(2)#1-Gd(1)-C(7)-O(4) -175.6(3) O(6)#2-Gd(1)-C(7)-O(4) -104.3(3) O(1)-Gd(1)-C(7)-O(4) -35.4(3) O(7)-Gd(1)-C(7)-O(4) 41.0(3) O(8)-Gd(1)-C(7)-O(4) 113.8(3) ______
194 Table A6-4. Hydrogen bonds for Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) [Å and °] ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(8)-H(8O)...O(9) 0.79(6) 1.93(6) 2.698(5) 165(6) ______
Figure A6-1: (a) shows a perspective drawing of the contents of the asymmetric unit for Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). Nonhydrogen atoms are represented by thermal vibration ellipsoids drawn to encompass 50% of their electron density. Hydrogen atoms are represented by arbitrarily-small spheres, which are in no way representative of their true thermal motion.
195
Figure A6-2: show projections of the unit cell when viewed down the a-axis of the unit cell in crystalline Gd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) with atoms represented as in Figure 1. Hydrogen atoms have been omitted for clarity.
196 APPENDIX A7: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (7) [Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO)]
Wake Forest University X-Ray Code: a99o
Table A8-1 Crystal data and structure refinement for Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______
Identification code a99o2_0m Empirical formula C48 H56 Eu2 F12 N4 O18 Formula weight 1508.89 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 6 Space group C2/c – C 2h (No. 15) Unit cell dimensions a = 23.300(3) Å b = 11.229(1) Å, β = 108.658(1)° c = 23.285(3) Å Volume 5771.9(12) Å3 Z 4 formula units Density (calculated) 1.736 g/cm3 Absorption coefficient 2.264 mm-1 F(000) 3000 Crystal size 0.13 x 0.09 x 0.05 mm3 Theta range for data collection 3.95 to 30.05° Index ranges -32≤h≤31, -15≤k≤15, -32≤l≤32 Independent reflections 8404 [R(int) = 0.0434] Completeness to theta = 30.05° 99.2 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.7462 and 0.6210 Refinement method Full-matrix least-squares on F2 Data / parameters 8404 / 390 Goodness-of-fit on F2 1.180
Final R indices [7238 I>2σ(I) data] R1 = 0.0426, wR2 = 0.0899
R indices (all data) R1 = 0.0527, wR2 = 0.0933 Largest diff. peak and hole 1.909 and -2.036 e-/Å3 ______
197 Table A8-2. Bond lengths [Å] and angles [°] for Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - a,b,c 2(Et2NCHO) ______Eu(1)-O(2)#1 2.340(2) O(3)-C(7) 1.248(4) Eu(1)-O(6)#2 2.386(3) O(4)-C(7) 1.261(4) Eu(1)-O(1) 2.391(2) O(5)-C(14) 1.234(4) Eu(1)-O(7) 2.407(3) O(6)-C(14) 1.261(4) Eu(1)-O(8) 2.434(3) C(1)-C(2) 1.505(7) Eu(1)-O(4) 2.479(3) C(5)-C(6) 1.505(7) Eu(1)-O(3) 2.487(3) C(7)-C(8) 1.502(5) Eu(1)-O(5)#3 2.511(3) C(11)-C(14) 1.483(5) Eu(1)-O(6)#3 2.725(3) C(2)-C(3) 1.383(4) F(1)-C(3) 1.345(4) C(3)-C(4) 1.382(5) F(2)-C(4) 1.339(4) C(4)-C(5) 1.381(4) F(3)-C(9) 1.343(4) C(8)-C(13) 1.396(5) F(4)-C(10) 1.340(4) C(8)-C(9) 1.382(5) F(5)-C(12) 1.340(4) C(9)-C(10) 1.378(5) F(6)-C(13) 1.336(4) C(10)-C(11) 1.396(5) O(1)-C(1) 1.249(3) C(11)-C(12) 1.386(5) O(2)-C(6) 1.247(3) C(12)-C(13) 1.387(5) O(7)-C(15) 1.235(5) N(1)-C(15) 1.319(5) O(9)-C(22) 1.224(6) N(2)-C(22) 1.340(6) N(1)-C(16) 1.460(6) N(2)-C(23) 1.454(7) N(1)-C(18) 1.472(6) N(2)-C(25) 1.457(6) C(16)-C(17) 1.488(9) C(23)-C(24) 1.499(9) C(18)-C(19) 1.520(9) C(25)-C(26) 1.484(7) O(8)-C(20) 1.436(6) O(8)-H(8O) 0.81(6) C(20)-C(21) 1.470(9) O(1)-Eu(1)-O(8) 149.43(10) O(2)#1-Eu(1)-O(6)#2 74.61(9) O(7)-Eu(1)-O(8) 74.05(10) O(2)#1-Eu(1)-O(1) 131.61(9) O(2)#1-Eu(1)-O(4) 129.74(9) O(6)#2-Eu(1)-O(1) 72.37(9) O(6)#2-Eu(1)-O(4) 86.96(10) O(2)#1-Eu(1)-O(7) 139.27(10) O(1)-Eu(1)-O(4) 82.55(10) O(6)#2-Eu(1)-O(7) 145.14(9) O(7)-Eu(1)-O(4) 75.39(9) O(1)-Eu(1)-O(7) 75.66(9) O(8)-Eu(1)-O(4) 93.70(11) O(2)#1-Eu(1)-O(8) 72.95(10) O(2)#1-Eu(1)-O(3) 77.57(9) O(6)#2-Eu(1)-O(8) 137.95(10) O(6)#2-Eu(1)-O(3) 74.54(9)
198 O(1)-Eu(1)-O(3) 124.53(9) C(4)-C(3)-C(2) 121.7(4) O(7)-Eu(1)-O(3) 114.29(9) F(2)-C(4)-C(5) 120.3(3) O(8)-Eu(1)-O(3) 72.95(10) F(2)-C(4)-C(3) 118.2(3) O(4)-Eu(1)-O(3) 52.34(9) C(5)-C(4)-C(3) 121.4(3) O(2)#1-Eu(1)-O(5)#3 78.31(10) C(4)#6-C(5)-C(4) 117.1(4) O(6)#2-Eu(1)-O(5)#3 120.02(9) C(4)#6-C(5)-C(6) 121.5(2) O(1)-Eu(1)-O(5)#3 88.69(10) C(4)-C(5)-C(6) 121.5(2) O(7)-Eu(1)-O(5)#3 72.17(9) O(2)#6-C(6)-O(2) 129.4(4) O(8)-Eu(1)-O(5)#3 78.30(10) O(2)#6-C(6)-C(5) 115.3(2) O(4)-Eu(1)-O(5)#3 147.55(10) O(2)-C(6)-C(5) 115.3(2) O(3)-Eu(1)-O(5)#3 146.74(9) O(3)-C(7)-O(4) 121.6(3) O(2)#1-Eu(1)-O(6)#3 69.29(8) O(3)-C(7)-C(8) 118.2(3) O(6)#2-Eu(1)-O(6)#3 71.17(9) O(4)-C(7)-C(8) 120.2(3) O(1)-Eu(1)-O(6)#3 67.13(8) C(9)-C(8)-C(13) 116.0(3) O(7)-Eu(1)-O(6)#3 108.49(8) C(9)-C(8)-C(7) 122.0(3) O(8)-Eu(1)-O(6)#3 119.51(9) C(13)-C(8)-C(7) 122.0(3) O(4)-Eu(1)-O(6)#3 146.59(9) F(3)-C(9)-C(10) 117.2(3) O(3)-Eu(1)-O(6)#3 137.20(8) F(3)-C(9)-C(8) 120.4(3) O(5)#3-Eu(1)-O(6)#3 49.26(8) C(10)-C(9)-C(8) 122.4(3) C(1)-O(1)-Eu(1) 138.6(3) F(4)-C(10)-C(9) 119.1(3) C(6)-O(2)-Eu(1)#4 138.7(3) F(4)-C(10)-C(11) 118.9(3) C(7)-O(3)-Eu(1) 93.0(2) C(9)-C(10)-C(11) 122.0(3) C(7)-O(4)-Eu(1) 93.1(2) C(12)-C(11)-C(10) 115.7(3) C(14)-O(5)-Eu(1)#5 99.4(2) C(12)-C(11)-C(14) 123.8(3) C(14)-O(6)-Eu(1)#2 159.5(2) C(10)-C(11)-C(14) 120.5(3) C(14)-O(6)-Eu(1)#5 88.5(2) F(5)-C(12)-C(11) 118.7(3) Eu(1)#2-O(6)-Eu(1)#5 108.76(9) F(5)-C(12)-C(13) 119.0(3) O(1)#6-C(1)-O(1) 128.5(5) C(11)-C(12)-C(13) 122.3(3) O(1)#6-C(1)-C(2) 115.7(2) F(6)-C(13)-C(12) 116.9(3) O(1)-C(1)-C(2) 115.7(2) F(6)-C(13)-C(8) 121.4(3) C(3)-C(2)-C(3)#6 116.7(4) C(12)-C(13)-C(8) 121.6(3) C(3)-C(2)-C(1) 121.6(2) O(5)-C(14)-O(6) 122.8(3) C(3)#6-C(2)-C(1) 121.6(2) O(5)-C(14)-C(11) 118.8(3) F(1)-C(3)-C(4) 117.8(3) O(6)-C(14)-C(11) 118.3(3) F(1)-C(3)-C(2) 120.4(3)
199 Table A8-3. Torsion angles [°] for Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______O(2)#1-Eu(1)-O(1)-C(1) 20.4(3) O(6)#2-Eu(1)-O(1)-C(1) -28.7(3) O(7)-Eu(1)-O(1)-C(1) 165.4(3) O(8)-Eu(1)-O(1)-C(1) 157.5(2) O(4)-Eu(1)-O(1)-C(1) -117.9(3) O(3)-Eu(1)-O(1)-C(1) -84.8(3) O(5)#3-Eu(1)-O(1)-C(1) 93.4(3) O(6)#3-Eu(1)-O(1)-C(1) 47.8(3) O(2)#1-Eu(1)-O(3)-C(7) -175.4(2) O(6)#2-Eu(1)-O(3)-C(7) -98.2(2) O(1)-Eu(1)-O(3)-C(7) -43.1(3) O(7)-Eu(1)-O(3)-C(7) 45.8(2) O(8)-Eu(1)-O(3)-C(7) 108.8(2) O(4)-Eu(1)-O(3)-C(7) 0.1(2) O(5)#3-Eu(1)-O(3)-C(7) 140.2(2) O(6)#3-Eu(1)-O(3)-C(7) -135.9(2) O(2)#1-Eu(1)-O(4)-C(7) 5.6(3) O(6)#2-Eu(1)-O(4)-C(7) 72.7(2) O(1)-Eu(1)-O(4)-C(7) 145.3(2) O(7)-Eu(1)-O(4)-C(7) -137.6(3) O(8)-Eu(1)-O(4)-C(7) -65.2(2) O(3)-Eu(1)-O(4)-C(7) -0.1(2) O(5)#3-Eu(1)-O(4)-C(7) -139.1(2) O(6)#3-Eu(1)-O(4)-C(7) 120.8(2) Eu(1)-O(1)-C(1)-O(1)#6 -9.19(19) Eu(1)-O(1)-C(1)-C(2) 170.82(19) O(1)#6-C(1)-C(2)-C(3) 48.8(2) O(1)-C(1)-C(2)-C(3) -131.2(2) O(1)#6-C(1)-C(2)-C(3)#6 -131.2(2) O(1)-C(1)-C(2)-C(3)#6 48.8(2) C(3)#6-C(2)-C(3)-F(1) -176.8(4) C(1)-C(2)-C(3)-F(1) 3.2(4) C(3)#6-C(2)-C(3)-C(4) -0.1(2) C(1)-C(2)-C(3)-C(4) 179.9(2)
200 F(1)-C(3)-C(4)-F(2) -0.4(5) C(2)-C(3)-C(4)-F(2) -177.3(3) F(1)-C(3)-C(4)-C(5) 177.0(3) C(2)-C(3)-C(4)-C(5) 0.1(5) F(2)-C(4)-C(5)-C(4)#6 177.3(4) C(3)-C(4)-C(5)-C(4)#6 -0.1(2) F(2)-C(4)-C(5)-C(6) -2.7(4) C(3)-C(4)-C(5)-C(6) 179.9(2) Eu(1)#4-O(2)-C(6)-O(2)#6 8.67(19) Eu(1)#4-O(2)-C(6)-C(5) -171.32(19) C(4)#6-C(5)-C(6)-O(2)#6 130.6(2) C(4)-C(5)-C(6)-O(2)#6 -49.4(2) C(4)#6-C(5)-C(6)-O(2) -49.4(2) C(4)-C(5)-C(6)-O(2) 130.6(2) Eu(1)-O(3)-C(7)-O(4) -0.1(4) Eu(1)-O(3)-C(7)-C(8) 179.9(3) Eu(1)-O(4)-C(7)-O(3) 0.1(4) Eu(1)-O(4)-C(7)-C(8) -179.9(3) O(3)-C(7)-C(8)-C(9) 28.8(5) O(4)-C(7)-C(8)-C(9) -151.2(4) O(3)-C(7)-C(8)-C(13) -149.9(4) O(4)-C(7)-C(8)-C(13) 30.1(5) C(13)-C(8)-C(9)-F(3) -179.4(4) C(7)-C(8)-C(9)-F(3) 1.9(6) C(13)-C(8)-C(9)-C(10) -0.3(6) C(7)-C(8)-C(9)-C(10) -179.0(4) F(3)-C(9)-C(10)-F(4) 0.3(6) C(8)-C(9)-C(10)-F(4) -178.8(4) F(3)-C(9)-C(10)-C(11) 179.2(4) C(8)-C(9)-C(10)-C(11) 0.1(6) F(4)-C(10)-C(11)-C(12) 179.7(3) C(9)-C(10)-C(11)-C(12) 0.8(6) F(4)-C(10)-C(11)-C(14) -0.7(6) C(9)-C(10)-C(11)-C(14) -179.6(4) C(10)-C(11)-C(12)-F(5) 179.7(3) C(14)-C(11)-C(12)-F(5) 0.1(6)
201 C(10)-C(11)-C(12)-C(13) -1.6(6) C(14)-C(11)-C(12)-C(13) 178.9(3) F(5)-C(12)-C(13)-F(6) -2.4(5) C(11)-C(12)-C(13)-F(6) 178.8(3) F(5)-C(12)-C(13)-C(8) -179.8(3) C(11)-C(12)-C(13)-C(8) 1.5(6) C(9)-C(8)-C(13)-F(6) -177.7(3) C(7)-C(8)-C(13)-F(6) 1.0(6) C(9)-C(8)-C(13)-C(12) -0.5(6) C(7)-C(8)-C(13)-C(12) 178.3(3) Eu(1)#5-O(5)-C(14)-O(6) -1.4(4) Eu(1)#5-O(5)-C(14)-C(11) -179.7(3) Eu(1)#2-O(6)-C(14)-O(5) 149.5(5) Eu(1)#5-O(6)-C(14)-O(5) 1.3(4) Eu(1)#2-O(6)-C(14)-C(11) -32.3(8) Eu(1)#5-O(6)-C(14)-C(11) 179.5(3) C(12)-C(11)-C(14)-O(5) -97.1(4) C(10)-C(11)-C(14)-O(5) 83.4(5) C(12)-C(11)-C(14)-O(6) 84.6(4) C(10)-C(11)-C(14)-O(6) -95.0(4) O(2)#1-Eu(1)-O(7)-C(15) 97.9(4) O(6)#2-Eu(1)-O(7)-C(15) -64.9(4) O(1)-Eu(1)-O(7)-C(15) -41.0(3) O(8)-Eu(1)-O(7)-C(15) 134.8(4) O(4)-Eu(1)-O(7)-C(15) -126.9(4) O(3)-Eu(1)-O(7)-C(15) -162.8(3) O(5)#3-Eu(1)-O(7)-C(15) 52.3(3) O(6)#3-Eu(1)-O(7)-C(15) 18.4(4) Eu(1)-O(7)-C(15)-N(1) -175.4(3) C(16)-N(1)-C(15)-O(7) 2.7(7) C(18)-N(1)-C(15)-O(7) -178.9(5) C(15)-N(1)-C(16)-C(17) 89.2(6) C(18)-N(1)-C(16)-C(17) -89.2(6) C(15)-N(1)-C(18)-C(19) 105.0(6) C(16)-N(1)-C(18)-C(19) -76.6(7) ______
202 Table A8-4. Hydrogen bonds for Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) [Å and °]a,b ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(8)-H(8O)...O(9) 0.81(6) 1.92(6) 2.696(4) 160(5) ______
Figure A8-1: shows a perspective drawing of the contents of the asymmetric unit for Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). The europium atom is represented by a large cross-hatched sphere; fluorine atoms are represented by medium-sized dotted spheres; oxygen and nitrogen atoms are represented by medium-sized shaded spheres and carbon and hydrogen atoms are represented by medium and small open spheres, respectively.
203
Figure A8-2: show projections of the unit cell when viewed down the b-axis of the unit cell in crystalline Eu2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) with atoms represented as in Figure A8-1. Hydrogen atoms have been omitted for clarity.
204 APPENDIX A8: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (8) [La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO)]
Wake Forest University X-Ray Code: a46o
Table A6-1 Crystal data and structure refinement for La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______Identification code a46o2m Empirical formula C48 H56 F12 La2 N4 O18 Formula weight 1482.79 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 6 Space group C2/c– C 2h (No. 15) Unit cell dimensions a = 23.542(2) Å b = 11.3837(8) Å, β = 108.640(1)° c = 23.623(2) Å Volume 5998.9(7) Å3 Z 4 Density (calculated) 1.642 g/cm3 Absorption coefficient 1.512 mm-1 F(000) 2952 Crystal size 0.268 x 0.156 x 0.088 mm3 Theta range for data collection 3.90 to 30.05° Index ranges -33≤h≤33, -16≤k≤15, -33≤l≤33 Independent reflections 8664 [R(int) = 0.0432] Completeness to theta = 30.05° 98.6 % Absorption correction Multi-scan (SADABS) Refinement method Full-matrix least-squares on F2 Data / parameters 8664 / 390 Goodness-of-fit on F2 1.064
Final R indices [7345 I>2σ(I) data] R1 = 0.0396, wR2 = 0.0892
R indices (all data) R1 = 0.0498, wR2 = 0.0938 Largest diff. peak and hole 1.515 and -1.081 e-/Å3
______
205 Table A7-2. Bond lengths [Å] and angles [°] for La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______La(1)-O(2)#1 2.439(2) O(3)-C(7) 1.247(4) La(1)-O(1) 2.482(2) O(4)-C(7) 1.251(4) La(1)-O(6)#2 2.494(2) O(5)-C(14) 1.234(4) La(1)-O(7) 2.508(2) O(6)-C(14) 1.257(4) La(1)-O(8) 2.527(2) C(1)-C(2) 1.509(5) La(1)-O(3) 2.570(2) C(5)-C(6) 1.512(5) La(1)-O(4) 2.581(2) C(7)-C(8) 1.514(4) La(1)-O(5)#3 2.625(2) C(11)-C(14) 1.505(4) La(1)-O(6)#3 2.761(2) C(2)-C(3) 1.380(4) F(1)-C(3) 1.344(3) C(3)-C(4) 1.381(4) F(2)-C(4) 1.340(3) C(4)-C(5) 1.379(4) F(3)-C(9) 1.336(4) C(8)-C(13) 1.390(4) F(4)-C(10) 1.339(4) C(8)-C(9) 1.393(4) F(5)-C(12) 1.341(3) C(9)-C(10) 1.372(4) F(6)-C(13) 1.337(4) C(10)-C(11) 1.380(4) O(1)-C(1) 1.248(3) C(11)-C(12) 1.382(4) O(2)-C(6) 1.240(3) C(12)-C(13) 1.382(4) O(7)-C(15) 1.233(4) N(1)-C(15) 1.320(4) O(9)-C(22) 1.228(5) N(2)-C(22) 1.331(5) N(1)-C(16) 1.464(6) N(2)-C(23) 1.456(7) N(1)-C(18) 1.470(5) N(2)-C(25) 1.462(5) C(16)-C(17) 1.486(7) C(23)-C(24) 1.495(8) C(18)-C(19) 1.520(8) C(25)-C(26) 1.491(6) O(8)-C(20) 1.416(7) O(8)-H(8O) 0.81(5) C(20)-C(21) 1.354(9) O(6)#2-La(1)-O(8) 137.34(8) O(2)#1-La(1)-O(1) 130.63(7) O(7)-La(1)-O(8) 75.46(9) O(2)#1-La(1)-O(6)#2 73.07(7) O(2)#1-La(1)-O(3) 78.19(8) O(1)-La(1)-O(6)#2 71.49(7) O(1)-La(1)-O(3) 122.88(8) O(2)#1-La(1)-O(7) 140.06(8) O(6)#2-La(1)-O(3) 75.05(7) O(1)-La(1)-O(7) 75.84(7) O(7)-La(1)-O(3) 115.01(8) O(6)#2-La(1)-O(7) 145.30(7) O(8)-La(1)-O(3) 73.61(8) O(2)#1-La(1)-O(8) 72.76(8) O(2)#1-La(1)-O(4) 128.61(8) O(1)-La(1)-O(8) 151.06(8) O(1)-La(1)-O(4) 83.70(8)
206 O(6)#2-La(1)-O(4) 88.84(8) F(2)-C(4)-C(5) 120.4(3) O(7)-La(1)-O(4) 76.16(8) F(2)-C(4)-C(3) 118.5(3) O(8)-La(1)-O(4) 92.98(9) C(5)-C(4)-C(3) 121.0(3) O(3)-La(1)-O(4) 50.52(7) C(4)#6-C(5)-C(4) 117.6(4) O(2)#1-La(1)-O(5)#3 78.92(8) C(4)-C(5)-C(6) 121.19(18) O(1)-La(1)-O(5)#3 89.06(8) O(2)#6-C(6)-O(2) 128.9(4) O(6)#2-La(1)-O(5)#3 118.62(7) O(2)-C(6)-C(5) 115.57(18) O(7)-La(1)-O(5)#3 71.49(8) O(3)-C(7)-O(4) 123.3(3) O(8)-La(1)-O(5)#3 78.44(8) O(3)-C(7)-C(8) 117.7(3) O(3)-La(1)-O(5)#3 148.00(8) O(4)-C(7)-C(8) 119.0(3) O(4)-La(1)-O(5)#3 147.64(8) C(13)-C(8)-C(9) 116.0(3) O(2)#1-La(1)-O(6)#3 69.42(7) C(13)-C(8)-C(7) 122.6(3) O(1)-La(1)-O(6)#3 67.23(7) C(9)-C(8)-C(7) 121.4(3) O(6)#2-La(1)-O(6)#3 71.00(7) F(3)-C(9)-C(10) 117.6(3) O(7)-La(1)-O(6)#3 106.66(7) F(3)-C(9)-C(8) 120.6(3) O(8)-La(1)-O(6)#3 118.35(8) C(10)-C(9)-C(8) 121.8(3) O(3)-La(1)-O(6)#3 138.33(7) F(4)-C(10)-C(9) 119.1(3) O(4)-La(1)-O(6)#3 148.46(8) F(4)-C(10)-C(11) 118.8(3) O(5)#3-La(1)-O(6)#3 48.06(7) C(9)-C(10)-C(11) 122.0(3) C(1)-O(1)-La(1) 139.2(2) C(10)-C(11)-C(12) 116.7(3) C(6)-O(2)-La(1)#4 140.1(2) C(10)-C(11)-C(14) 120.7(3) C(7)-O(3)-La(1) 93.41(18) C(12)-C(11)-C(14) 122.6(3) C(7)-O(4)-La(1) 92.76(19) F(5)-C(12)-C(13) 118.9(3) C(14)-O(5)-La(1)#5 97.56(19) F(5)-C(12)-C(11) 119.4(3) C(14)-O(6)-La(1)#2 157.7(2) C(13)-C(12)-C(11) 121.7(3) C(14)-O(6)-La(1)#5 90.54(18) F(6)-C(13)-C(12) 117.5(3) La(1)#2-O(6)-La(1)#5 108.94(7) F(6)-C(13)-C(8) 120.7(3) O(1)-C(1)-O(1)#6 128.8(4) C(12)-C(13)-C(8) 121.7(3) O(1)-C(1)-C(2) 115.58(18) O(5)-C(14)-O(6) 123.8(3) O(1)#6-C(1)-C(2) 115.58(18) O(5)-C(14)-C(11) 118.6(3) C(3)-C(2)-C(3)#6 116.9(4) O(6)-C(14)-C(11) 117.6(3) C(3)-C(2)-C(1) 121.57(18) C(15)-O(7)-La(1) 129.0(2) C(3)#6-C(2)-C(1) 121.57(18) C(20)-O(8)-La(1) 127.2(4) F(1)-C(3)-C(2) 120.4(3) C(20)-O(8)-H(8O) 103(3) F(1)-C(3)-C(4) 117.8(3) La(1)-O(8)-H(8O) 122(3) C(2)-C(3)-C(4) 121.7(3)
207 Table A7-3. Torsion angles [°] for La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). ______O(2)#1-La(1)-O(1)-C(1) 16.3(3) O(6)#2-La(1)-O(1)-C(1) -29.9(2) O(7)-La(1)-O(1)-C(1) 161.9(3) O(8)-La(1)-O(1)-C(1) 154.5(2) O(3)-La(1)-O(1)-C(1) -87.2(2) O(4)-La(1)-O(1)-C(1) -120.8(2) O(5)#3-La(1)-O(1)-C(1) 90.8(2) O(6)#3-La(1)-O(1)-C(1) 46.7(2) O(2)#1-La(1)-O(3)-C(7) -176.7(2) O(1)-La(1)-O(3)-C(7) -45.7(2) O(6)#2-La(1)-O(3)-C(7) -101.3(2) O(7)-La(1)-O(3)-C(7) 43.2(2) O(8)-La(1)-O(3)-C(7) 108.0(2) O(4)-La(1)-O(3)-C(7) -0.22(19) O(5)#3-La(1)-O(3)-C(7) 138.1(2) O(6)#3-La(1)-O(3)-C(7) -137.56(18) O(2)#1-La(1)-O(4)-C(7) 4.6(3) O(1)-La(1)-O(4)-C(7) 143.2(2) O(6)#2-La(1)-O(4)-C(7) 71.7(2) O(7)-La(1)-O(4)-C(7) -139.9(2) O(8)-La(1)-O(4)-C(7) -65.6(2) O(3)-La(1)-O(4)-C(7) 0.22(19) O(5)#3-La(1)-O(4)-C(7) -138.6(2) O(6)#3-La(1)-O(4)-C(7) 120.8(2) La(1)-O(1)-C(1)-O(1)#6 -7.82(16) La(1)-O(1)-C(1)-C(2) 172.17(16) O(1)-C(1)-C(2)-C(3) -130.22(19) O(1)#6-C(1)-C(2)-C(3) 49.78(19) O(1)-C(1)-C(2)-C(3)#6 49.78(19) O(1)#6-C(1)-C(2)-C(3)#6 -130.22(19) C(3)#6-C(2)-C(3)-F(1) -176.5(3) C(1)-C(2)-C(3)-F(1) 3.5(3) C(3)#6-C(2)-C(3)-C(4) -0.2(2) C(1)-C(2)-C(3)-C(4) 179.8(2)
208 F(1)-C(3)-C(4)-F(2) -0.7(4) C(2)-C(3)-C(4)-F(2) -177.1(2) F(1)-C(3)-C(4)-C(5) 176.8(2) C(2)-C(3)-C(4)-C(5) 0.4(4) F(2)-C(4)-C(5)-C(4)#6 177.3(3) C(3)-C(4)-C(5)-C(4)#6 -0.2(2) F(2)-C(4)-C(5)-C(6) -2.7(3) C(3)-C(4)-C(5)-C(6) 179.8(2) La(1)#4-O(2)-C(6)-O(2)#6 6.00(17) La(1)#4-O(2)-C(6)-C(5) -174.00(17) C(4)#6-C(5)-C(6)-O(2)#6 128.48(19) C(4)-C(5)-C(6)-O(2)#6 -51.52(19) C(4)#6-C(5)-C(6)-O(2) -51.52(19) C(4)-C(5)-C(6)-O(2) 128.48(19) La(1)-O(3)-C(7)-O(4) 0.4(4) La(1)-O(3)-C(7)-C(8) -179.8(2) La(1)-O(4)-C(7)-O(3) -0.4(4) La(1)-O(4)-C(7)-C(8) 179.8(3) O(3)-C(7)-C(8)-C(13) -147.3(3) O(4)-C(7)-C(8)-C(13) 32.5(5) O(3)-C(7)-C(8)-C(9) 31.6(5) O(4)-C(7)-C(8)-C(9) -148.7(3) C(13)-C(8)-C(9)-F(3) -179.2(3) C(7)-C(8)-C(9)-F(3) 1.9(5) C(13)-C(8)-C(9)-C(10) -1.1(5) C(7)-C(8)-C(9)-C(10) 180.0(3) F(3)-C(9)-C(10)-F(4) -0.3(5) C(8)-C(9)-C(10)-F(4) -178.4(3) F(3)-C(9)-C(10)-C(11) 179.3(3) C(8)-C(9)-C(10)-C(11) 1.1(6) F(4)-C(10)-C(11)-C(12) 179.3(3) C(9)-C(10)-C(11)-C(12) -0.2(5) F(4)-C(10)-C(11)-C(14) 0.3(5) C(9)-C(10)-C(11)-C(14) -179.3(3) C(10)-C(11)-C(12)-F(5) 179.8(3) ______
209 Table A7-4. Hydrogen bonds for La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) [Å and °]. ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(8)-H(8O)...O(9) 0.81(5) 1.89(5) 2.691(4) 166(5) ______
Figure A7-1: A perspective drawing of the contents of the asymmetric unit for La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). Nonhydrogen atoms are represented by thermal vibration ellipsoids drawn to encompass 50% of their electron density. Hydrogen atoms are represented by arbitrarily-small spheres, which are in no way representative of their true thermal motion.
210
Figure A7-2: A projection of the unit cell when viewed down the b-axis in crystalline La2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) with atoms represented as arbitrarily small spheres, which are in no way representative of their true thermal motion.. Hydrogen atoms have been omitted for clarity.
211 APPENDIX A9: CRYSTAL STRUCTURE TABLES AND FIGURES FOR COMPOUND (9) [Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO)]
Wake Forest University X-Ray Code: a48o
Table A9-1 Crystal data and structure refinement for Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______Identification code a48o2m Empirical formula C48 H56 F12 N4 Nd2 O18 Formula weight 1493.45 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic 6 Space group C2/c– C 2h (No. 15) Unit cell dimensions a = 23.398(2) Å b = 11.301(1) Å, β = 108.634(1)° c = 23.425(2) Å Volume 5869.4(9) Å3 Z 4 Density (calculated) 1.690 g/cm3 Absorption coefficient 1.858 mm-1 F(000) 2976 Crystal size 0.18 x 0.05 x 0.02 mm3 Theta range for data collection 3.93 to 27.50° Index ranges -30≤h≤30, -14≤k≤14, -30≤l≤29 Independent reflections 6694 [R(int) = 0.0608] Completeness to theta = 27.50° 99.2 % Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.9638 and 0.7309 Refinement method Full-matrix least-squares on F2 Data / parameters 6694 / 390 Goodness-of-fit on F2 1.126
Final R indices [5694 I>2σ(I) data] R1 = 0.0486, wR2 = 0.1001
R indices (all data) R1 = 0.0605, wR2 = 0.1047 Largest diff. peak and hole 1.597 and -1.793 e-/Å3 ______
212 Table 3. Bond lengths [Å] and angles [°] for Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______Nd(1)-O(2)#1 2.381(3) O(3)-C(7) 1.243(5) Nd(1)-O(1) 2.431(3) O(4)-C(7) 1.260(6) Nd(1)-O(6)#2 2.436(3) O(5)-C(14) 1.234(6) Nd(1)-O(7) 2.447(3) O(6)-C(14) 1.253(5) Nd(1)-O(8) 2.475(4) C(1)-C(2) 1.518(8) Nd(1)-O(3) 2.523(3) C(5)-C(6) 1.505(9) Nd(1)-O(4) 2.527(3) C(7)-C(8) 1.513(6) Nd(1)-O(5)#3 2.559(3) C(11)-C(14) 1.500(6) Nd(1)-O(6)#3 2.729(3) C(2)-C(3) 1.382(6) F(1)-C(3) 1.349(5) C(3)-C(4) 1.373(6) F(2)-C(4) 1.337(5) C(4)-C(5) 1.387(6) F(3)-C(9) 1.336(5) C(8)-C(13) 1.387(6) F(4)-C(10) 1.334(5) C(8)-C(9) 1.389(6) F(5)-C(12) 1.345(5) C(9)-C(10) 1.373(7) F(6)-C(13) 1.336(5) C(10)-C(11) 1.396(6) O(1)-C(1) 1.244(4) C(11)-C(12) 1.375(6) O(2)-C(6) 1.247(4) C(12)-C(13) 1.389(6) O(7)-C(15) 1.232(6) N(1)-C(15) 1.316(7) O(9)-C(22) 1.228(7) N(2)-C(22) 1.344(7) N(1)-C(16) 1.459(8) N(2)-C(23) 1.455(9) N(1)-C(18) 1.473(8) N(2)-C(25) 1.454(7) C(16)-C(17) 1.485(10) C(23)-C(24) 1.506(11) C(18)-C(19) 1.504(11) C(25)-C(26) 1.490(9) O(8)-C(20) 1.433(8) O(8)-H(8O) 0.77(5) C(20)-C(21) 1.454(12) O(6)#2-Nd(1)-O(8) 137.80(12) O(2)#1-Nd(1)-O(1) 131.51(11) O(7)-Nd(1)-O(8) 74.46(13) O(2)#1-Nd(1)-O(6)#2 74.03(11) O(2)#1-Nd(1)-O(3) 77.67(11) O(1)-Nd(1)-O(6)#2 71.98(11) O(1)-Nd(1)-O(3) 123.58(12) O(2)#1-Nd(1)-O(7) 139.54(12) O(6)#2-Nd(1)-O(3) 74.65(11) O(1)-Nd(1)-O(7) 75.81(11) O(7)-Nd(1)-O(3) 114.55(11) O(6)#2-Nd(1)-O(7) 145.29(11) O(8)-Nd(1)-O(3) 73.40(12) O(2)#1-Nd(1)-O(8) 72.80(12) O(2)#1-Nd(1)-O(4) 129.13(11) O(1)-Nd(1)-O(8) 150.03(12) O(1)-Nd(1)-O(4) 82.93(12)
213 O(6)#2-Nd(1)-O(4) 87.91(12) C(4)-C(3)-C(2) 122.2(5) O(7)-Nd(1)-O(4) 75.53(12) F(2)-C(4)-C(3) 118.8(4) O(8)-Nd(1)-O(4) 93.25(13) F(2)-C(4)-C(5) 120.0(4) O(3)-Nd(1)-O(4) 51.57(11) C(3)-C(4)-C(5) 121.2(5) O(2)#1-Nd(1)-O(5)#3 78.67(12) C(4)-C(5)-C(4)#6 116.9(6) O(1)-Nd(1)-O(5)#3 89.02(12) C(4)-C(5)-C(6) 121.6(3) O(6)#2-Nd(1)-O(5)#3 119.40(11) C(4)#6-C(5)-C(6) 121.6(3) O(7)-Nd(1)-O(5)#3 71.97(12) O(2)-C(6)-O(2)#6 129.7(6) O(8)-Nd(1)-O(5)#3 78.32(12) O(2)-C(6)-C(5) 115.2(3) O(3)-Nd(1)-O(5)#3 147.35(12) O(2)#6-C(6)-C(5) 115.2(3) O(4)-Nd(1)-O(5)#3 147.50(12) O(3)-C(7)-O(4) 122.7(4) O(2)#1-Nd(1)-O(6)#3 69.64(10) O(3)-C(7)-C(8) 118.0(4) O(1)-Nd(1)-O(6)#3 67.24(10) O(4)-C(7)-C(8) 119.2(4) O(6)#2-Nd(1)-O(6)#3 71.08(11) C(13)-C(8)-C(9) 116.4(4) O(7)-Nd(1)-O(6)#3 107.77(10) C(13)-C(8)-C(7) 122.4(4) O(8)-Nd(1)-O(6)#3 119.10(11) C(9)-C(8)-C(7) 121.3(4) O(3)-Nd(1)-O(6)#3 137.67(10) F(3)-C(9)-C(10) 117.3(4) O(4)-Nd(1)-O(6)#3 147.42(11) F(3)-C(9)-C(8) 120.7(4) O(5)#3-Nd(1)-O(6)#3 48.76(10) C(10)-C(9)-C(8) 122.0(4) C(1)-O(1)-Nd(1) 138.4(3) F(4)-C(10)-C(9) 119.6(4) C(6)-O(2)-Nd(1)#4 138.9(3) F(4)-C(10)-C(11) 118.7(4) C(7)-O(3)-Nd(1) 93.1(3) C(9)-C(10)-C(11) 121.7(4) C(7)-O(4)-Nd(1) 92.5(3) C(12)-C(11)-C(10) 116.3(4) C(14)-O(5)-Nd(1)#5 98.3(3) C(12)-C(11)-C(14) 123.4(4) C(14)-O(6)-Nd(1)#2 158.3(3) C(10)-C(11)-C(14) 120.3(4) C(14)-O(6)-Nd(1)#5 89.7(3) F(5)-C(12)-C(11) 119.2(4) Nd(1)#2-O(6)-Nd(1)#5 108.85(11) F(5)-C(12)-C(13) 118.7(4) O(1)#6-C(1)-O(1) 129.5(6) C(11)-C(12)-C(13) 122.1(4) O(1)#6-C(1)-C(2) 115.2(3) F(6)-C(13)-C(8) 121.2(4) O(1)-C(1)-C(2) 115.2(3) F(6)-C(13)-C(12) 117.4(4) C(3)-C(2)-C(3)#6 116.3(6) C(8)-C(13)-C(12) 121.4(4) C(3)-C(2)-C(1) 121.9(3) O(5)-C(14)-O(6) 123.2(4) C(3)#6-C(2)-C(1) 121.9(3) O(5)-C(14)-C(11) 118.4(4) F(1)-C(3)-C(4) 117.9(4) O(6)-C(14)-C(11) 118.3(4) F(1)-C(3)-C(2) 119.8(4)
214 215 216
Table 6. Torsion angles [°] for Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) ______O(2)#1-Nd(1)-O(1)-C(1) 18.3(4) O(6)#2-Nd(1)-O(1)-C(1) -29.3(3) O(7)-Nd(1)-O(1)-C(1) 163.8(4) O(8)-Nd(1)-O(1)-C(1) 156.4(3) O(3)-Nd(1)-O(1)-C(1) -85.9(4) O(4)-Nd(1)-O(1)-C(1) -119.4(4) O(5)#3-Nd(1)-O(1)-C(1) 92.2(4) O(6)#3-Nd(1)-O(1)-C(1) 47.3(3) C(7)-Nd(1)-O(1)-C(1) -104.0(4) C(14)#3-Nd(1)-O(1)-C(1) 70.8(4) O(2)#1-Nd(1)-O(3)-C(7) -176.4(3) O(1)-Nd(1)-O(3)-C(7) -44.4(3) O(6)#2-Nd(1)-O(3)-C(7) -99.8(3) O(7)-Nd(1)-O(3)-C(7) 44.5(3) O(8)-Nd(1)-O(3)-C(7) 108.1(3) O(4)-Nd(1)-O(3)-C(7) 0.0(3) O(5)#3-Nd(1)-O(3)-C(7) 139.2(3) O(6)#3-Nd(1)-O(3)-C(7) -136.6(3) C(14)#3-Nd(1)-O(3)-C(7) -173.8(3) O(2)#1-Nd(1)-O(4)-C(7) 4.6(4) O(1)-Nd(1)-O(4)-C(7) 144.1(3) O(6)#2-Nd(1)-O(4)-C(7) 72.0(3) O(7)-Nd(1)-O(4)-C(7) -138.8(3) O(8)-Nd(1)-O(4)-C(7) -65.7(3) O(3)-Nd(1)-O(4)-C(7) 0.0(3) O(5)#3-Nd(1)-O(4)-C(7) -139.0(3) O(6)#3-Nd(1)-O(4)-C(7) 120.8(3) C(14)#3-Nd(1)-O(4)-C(7) 171.7(3) Nd(1)-O(1)-C(1)-O(1)#6 -8.5(2) Nd(1)-O(1)-C(1)-C(2) 171.5(2) O(1)#6-C(1)-C(2)-C(3) 49.4(3) O(1)-C(1)-C(2)-C(3) -130.6(3) O(1)#6-C(1)-C(2)-C(3)#6 -130.6(3) O(1)-C(1)-C(2)-C(3)#6 49.4(3)
216 217
C(3)#6-C(2)-C(3)-F(1) -177.3(5) C(1)-C(2)-C(3)-F(1) 2.7(5) C(3)#6-C(2)-C(3)-C(4) 0.1(3) C(1)-C(2)-C(3)-C(4) -179.9(3) F(1)-C(3)-C(4)-F(2) -0.1(6) C(2)-C(3)-C(4)-F(2) -177.5(4) F(1)-C(3)-C(4)-C(5) 177.2(3) C(2)-C(3)-C(4)-C(5) -0.2(7) F(2)-C(4)-C(5)-C(4)#6 177.4(5) C(3)-C(4)-C(5)-C(4)#6 0.1(3) F(2)-C(4)-C(5)-C(6) -2.6(5) C(3)-C(4)-C(5)-C(6) -179.9(3) Nd(1)#4-O(2)-C(6)-O(2)#6 7.1(2) Nd(1)#4-O(2)-C(6)-C(5) -172.9(2) C(4)-C(5)-C(6)-O(2) 129.5(3) C(4)#6-C(5)-C(6)-O(2) -50.5(3) C(4)-C(5)-C(6)-O(2)#6 -50.5(3) C(4)#6-C(5)-C(6)-O(2)#6 129.5(3) Nd(1)-O(3)-C(7)-O(4) 0.1(5) Nd(1)-O(3)-C(7)-C(8) -179.9(4) Nd(1)-O(4)-C(7)-O(3) -0.1(5) Nd(1)-O(4)-C(7)-C(8) 179.9(4) O(3)-C(7)-C(8)-C(13) -148.5(5) O(4)-C(7)-C(8)-C(13) 31.5(7) Nd(1)-C(7)-C(8)-C(13) -155(25) O(3)-C(7)-C(8)-C(9) 30.6(7) O(4)-C(7)-C(8)-C(9) -149.4(5) Nd(1)-C(7)-C(8)-C(9) 24(26) C(13)-C(8)-C(9)-F(3) -179.5(5) C(7)-C(8)-C(9)-F(3) 1.3(7) C(13)-C(8)-C(9)-C(10) -0.2(8) C(7)-C(8)-C(9)-C(10) -179.4(5) F(3)-C(9)-C(10)-F(4) -0.1(8) C(8)-C(9)-C(10)-F(4) -179.3(5) F(3)-C(9)-C(10)-C(11) 179.7(5) C(8)-C(9)-C(10)-C(11) 0.4(8)
217 218
F(4)-C(10)-C(11)-C(12) -179.9(4) C(9)-C(10)-C(11)-C(12) 0.3(7) F(4)-C(10)-C(11)-C(14) 0.2(7) C(9)-C(10)-C(11)-C(14) -179.5(5) C(10)-C(11)-C(12)-F(5) -179.9(4) C(14)-C(11)-C(12)-F(5) -0.1(7) C(10)-C(11)-C(12)-C(13) -1.2(7) C(14)-C(11)-C(12)-C(13) 178.7(4) C(9)-C(8)-C(13)-F(6) -178.1(4) C(7)-C(8)-C(13)-F(6) 1.0(7) C(9)-C(8)-C(13)-C(12) -0.6(7) C(7)-C(8)-C(13)-C(12) 178.5(4) F(5)-C(12)-C(13)-F(6) -2.3(7) C(11)-C(12)-C(13)-F(6) 179.0(4) F(5)-C(12)-C(13)-C(8) -179.9(4) C(11)-C(12)-C(13)-C(8) 1.4(7) Nd(1)#5-O(5)-C(14)-O(6) -1.4(5) Nd(1)#5-O(5)-C(14)-C(11) -179.7(3) Nd(1)#2-O(6)-C(14)-O(5) 150.6(6) Nd(1)#5-O(6)-C(14)-O(5) 1.3(5) Nd(1)#2-O(6)-C(14)-C(11) -31.2(10) Nd(1)#5-O(6)-C(14)-C(11) 179.6(3) Nd(1)#2-O(6)-C(14)-Nd(1)#5 149.3(8) C(12)-C(11)-C(14)-O(5) -97.0(6) C(10)-C(11)-C(14)-O(5) 82.9(6) C(12)-C(11)-C(14)-O(6) 84.7(6) C(10)-C(11)-C(14)-O(6) -95.4(5) C(12)-C(11)-C(14)-Nd(1)#5 -101(4) C(10)-C(11)-C(14)-Nd(1)#5 79(4) O(2)#1-Nd(1)-O(7)-C(15) 99.0(5) O(1)-Nd(1)-O(7)-C(15) -40.2(4) O(6)#2-Nd(1)-O(7)-C(15) -62.4(5) O(8)-Nd(1)-O(7)-C(15) 136.0(5) O(3)-Nd(1)-O(7)-C(15) -160.9(4) O(4)-Nd(1)-O(7)-C(15) -126.4(5) ______
218 219
Table 7. Hydrogen bonds for Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) [Å and °]. ______D-H...A d(D-H) d(H...A) d(D...A) <(DHA) ______O(8)-H(8O)...O(9) 0.77(5) 1.96(5) 2.696(6) 162(5) ______
Figure A9-1: A perspective drawing of the contents of the asymmetric unit for Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO). The neodymium atom is represented by a large cross-hatched sphere; fluorine atoms are represented by medium-sized dotted spheres; oxygen and nitrogen atoms are represented by medium-sized shaded spheres and carbon and hydrogen atoms are represented by medium and small open spheres, respectively.
219 220
Figure A9-2: A perspective drawing of the coordination sphere about a single Nd atom in crystalline Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) with atoms represented as in Figure A9-1.
Figure A9-3: A projection of the unit cell when viewed down the b-axis in crystalline Nd2(C8O4F4)3(EtOH)2(Et2NCHO)2 - 2(Et2NCHO) with atoms represented as in Figure A9-1. Hydrogen atoms have been omitted for clarity.
220 APPENDIX B: CHARACTERIZATION OF FRAMEWORKS 1-9
120
100
80
60
Weight % ST R 40
20
0 0 100 200 300 400 500 600 700 800 900 1000 Temperature (oC)
Figure B1: TGA of compound 1 using solvothermal (ST) and reflux (R) methods from
40oC-900oC at 5oC/min under air (40mL/min).
120
100
80
60
Weight % R ST 40
20
0 0 100 200 300 400 500 600 700 800 900 1000 Temperature (oC)
Figure B2: TGA of compound 2 using solvothermal (ST) and reflux (R) methods from
40oC-900oC at 5oC/min under air (40mL/min).
221 110
100
90
80
Weight % 70
60 ST
50 R
40 0 100 200 300 400 500 600 700 800 900 1000 temperature (oC)
Figure B3: TGA of compound 3 using solvothermal (ST) and reflux (R) methods from
40oC-900oC at 5oC/min under air (40mL/min).
La (2,5-TD C ) (D M F) (H O)-DMF (1 ) 2 3 2 2 800
700
600
500
400
Intensity reflux 300
200 100 sealed tube
0
0 102030405060 2 - Scale
Figure B4: X-ray powder diffraction spectra comparing the solvothermal method with the reflux method for compound 1.
222 Gd (2,5-TDC) (DM F) (H O) (2) 2 3 2 2 500 450
400
350
300 250 reflux Intensity 200
150
100
50 sealed tube 0
0 102030405060 2 - Scale
Figure B5: X-ray powder diffraction spectra comparing the solvothermal method with the reflux method for compound 2.
Eu (2,5-TDC) (DM F) (H O) (3) 2 3 2 2 180 160 140
120 reflux
100 80 Intensity 60
40 sealed tube 20
0
-20 0 102030405060 2 - Scale
Figure B6: X-ray powder diffraction spectra comparing the solvothermal method with the reflux method for compound 3.
223
400
350 (1)
300 (2) 250 (3)
200
(4) Intensity 150
(5) 100
50
0 4000 3500 3000 2500 2000 1500 1000 500 0 wavenumber (cm-1)
Figure B7: The IR spectra of Frameworks 5-9
1300 1200 1100 1000 (9) 900 800 (8) 700 600 (7) Intensity 500 400 (6) 300 200 (5) 100 0 simulated
0 102030405060
2 degree
Figure B8: The powder diffraction patterns of coordination polymer (5-9) along with the simulated (black).
224 simulated as-synthesized catalyst recovered rxn 1 500 catalyst recovered rxn 2
400
300
Intensity 200
100
0
0 102030405060 2 degree
Figure B9: The powder diffraction patterns of catalyst 3a before and after being reacted in the Biginelli reaction at 70oC.
simulated as-synthesized 600 catalyst recovered rxn 1 catalyst recovered rxn 2
500
400
300
Intensity 200
100
0
01020304050 2 degree
Figure B10: The powder diffraction patterns of catalyst 3a before and after being reacted in the Biginelli reaction at RT for 3 days.
225
Figure B8: 119Sn-NMR spectrum of 2,6-Bis(trimethyltin)-4,8-didodecyloxybenzo[1,2- b:4,5-b’]dithiophene (34)
226
Figure B9: 119Sn-NMR spectrum of 2,6-Bis(trimethyltin)-4,8-bis(2-ethylhexyloxy)benzo [1,2-b:4,5-b’]dithiophene (35)
227
Figure B10: 119Sn-NMR spectrum of 2,6-Bis(trimethyltin)-4,8-bis(1-ethylhexyloxy)benzo [1,2-b:4,5-b’]dithiophene (36)
228
Figure B11: 119Sn-NMR spectrum of 2,6-Bis(trimethyltin)-4,8-bis(1- pentylhexyloxy)benzo[1,2-b:4,5-b’]dithiophene (37)
229
) 0 0 2
-2 -2
-4 -4
-6
-6 -8
-8 1% CN in CB Current Density(mA/cm 2% CN in DCB Density(mA/cm^2) Current -10 4% CN in CB
0.0 0.3 0.6 0.9 0.0 0.5 1.0 Voltage(V) Voltage(V)
Figure B12: Additive concentration comparison for (a) 2% CN in DCB (b) 1% and 4% CN in CB.
Temperature (oC) 0 0 50 100 150 200 -0.5
-1
-1.5
-2
-2.5 -3 Heat Flow (W/g) Heat -3.5
-4
-4.5
-5
Figure B13: Differential Scanning Calorimetry of P13 at 20oC/min under nitrogen.
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237 8. License Contingent Upon Payment: While you may exercise the rights licensed immediately upon issuance of the license at the end of the licensing process for the transaction, provided that you have disclosed complete and accurate details of your proposed use, no license is finally effective unless and until full payment is received from you (either by publisher or by CCC) as provided in CCC's Billing and Payment terms and conditions. If full payment is not received on a timely basis, then any license preliminarily granted shall be deemed automatically revoked and shall be void as if never granted. Further, in the event that you breach any of these terms and conditions or any of CCC's Billing and Payment terms and conditions, the license is automatically revoked and shall be void as if never granted. Use of materials as described in a revoked license, as well as any use of the materials beyond the scope of an unrevoked license, may constitute copyright infringement and publisher reserves the right to take any and all action to protect its copyright in the materials.
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238 LIMITED LICENSE
The following terms and conditions apply only to specific license types:
15. Translation: This permission is granted for non-exclusive world English rights only unless your license was granted for translation rights. If you licensed translation rights you may only translate this content into the languages you requested. A professional translator must perform all translations and reproduce the content word for word preserving the integrity of the article. If this license is to re-use 1 or 2 figures then permission is granted for non-exclusive world rights in all languages.
16. Website: The following terms and conditions apply to electronic reserve and author websites: Electronic reserve: If licensed material is to be posted to website, the web site is to be password-protected and made available only to bona fide students registered on a relevant course if: This license was made in connection with a course, This permission is granted for 1 year only. You may obtain a license for future website posting, All content posted to the web site must maintain the copyright information line on the bottom of each image, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx or the Elsevier homepage for books at http://www.elsevier.com , and Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
17. Author website for journals with the following additional clauses:
All content posted to the web site must maintain the copyright information line on the bottom of each image, and he permission granted is limited to the personal version of your paper. You are not allowed to download and post the published electronic version of your article (whether PDF or HTML, proof or final version), nor may you scan the printed edition to create an electronic version, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx , As part of our normal production process, you will receive an e-mail notice when your article appears on Elsevier’s online service ScienceDirect (www.sciencedirect.com). That e-mail will include the article’s Digital Object Identifier (DOI). This number provides the electronic link to the published article and should be included in the posting of your personal version. We ask that you wait until you receive this e-mail and have the DOI to do any posting. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
239 18. Author website for books with the following additional clauses: Authors are permitted to place a brief summary of their work online only. A hyper-text must be included to the Elsevier homepage at http://www.elsevier.com
All content posted to the web site must maintain the copyright information line on the bottom of each image You are not allowed to download and post the published electronic version of your chapter, nor may you scan the printed edition to create an electronic version. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
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20. Thesis/Dissertation: If your license is for use in a thesis/dissertation your thesis may be submitted to your institution in either print or electronic form. Should your thesis be published commercially, please reapply for permission. These requirements include permission for the Library and Archives of Canada to supply single copies, on demand, of the complete thesis and include permission for UMI to supply single copies, on demand, of the complete thesis. Should your thesis be published commercially, please reapply for permission.
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241 ELSEVIER LICENSE TERMS AND CONDITIONS
Mar 23, 2011
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Licensed content publication Synthetic Metals
Licensed content title Synthesis, structure, and electrochemistry of N-(3-thenoyl)fluorosulfonimide and bis(2- thenoic)imide. Preparation of polymers containing the fluorosulfonimide group
Licensed content author Christopher M. MacNeill, Jian Dai, Cynthia S. Day, Stephen P. Lazar, S. Jarrett Howell, Ronald E. Noftle
242 Licensed content date August 2009
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243 Terms and Conditions
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244 8. License Contingent Upon Payment: While you may exercise the rights licensed immediately upon issuance of the license at the end of the licensing process for the transaction, provided that you have disclosed complete and accurate details of your proposed use, no license is finally effective unless and until full payment is received from you (either by publisher or by CCC) as provided in CCC's Billing and Payment terms and conditions. If full payment is not received on a timely basis, then any license preliminarily granted shall be deemed automatically revoked and shall be void as if never granted. Further, in the event that you breach any of these terms and conditions or any of CCC's Billing and Payment terms and conditions, the license is automatically revoked and shall be void as if never granted. Use of materials as described in a revoked license, as well as any use of the materials beyond the scope of an unrevoked license, may constitute copyright infringement and publisher reserves the right to take any and all action to protect its copyright in the materials.
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245 LIMITED LICENSE
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246 18. Author website for books with the following additional clauses: Authors are permitted to place a brief summary of their work online only. A hyper-text must be included to the Elsevier homepage at http://www.elsevier.com
All content posted to the web site must maintain the copyright information line on the bottom of each image You are not allowed to download and post the published electronic version of your chapter, nor may you scan the printed edition to create an electronic version. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
19. Website (regular and for author): A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx. or for books to the Elsevier homepage at http://www.elsevier.com
20. Thesis/Dissertation: If your license is for use in a thesis/dissertation your thesis may be submitted to your institution in either print or electronic form. Should your thesis be published commercially, please reapply for permission. These requirements include permission for the Library and Archives of Canada to supply single copies, on demand, of the complete thesis and include permission for UMI to supply single copies, on demand, of the complete thesis. Should your thesis be published commercially, please reapply for permission.
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248 ELSEVIER LICENSE TERMS AND CONDITIONS
Mar 24, 2011
This is a License Agreement between Christopher MacNeill ("You") and Elsevier ("Elsevier") provided by Copyright Clearance Center ("CCC"). The license consists of your order details, the terms and conditions provided by Elsevier, and the payment terms and conditions.
All payments must be made in full to CCC. For payment instructions, please see information listed at the bottom of this form.
Supplier Elsevier Limited The Boulevard,Langford Lane Kidlington,Oxford,OX5 1GB,UK
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Pfafftown, NC 27040
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License date Mar 24, 2011
Licensed content publisher Elsevier
Licensed content publication Synthetic Metals
Licensed content title A cyclopentadithiophene/ thienopyrrole- dione-based donor–acceptor copolymer for organic solar cells
Licensed content author Christopher M. MacNeill, Eric D. Peterson, Ronald E. Noftle, David L. Carroll, Robert C. Coffin
Licensed content date 22 March 2011
249 Licensed content volume number n/a
Licensed content issue number n/a
Number of pages 1
Start Page
End Page
Type of Use reuse in a thesis/dissertation
Intended publisher of new work other
Format both print and electronic
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Will you be translating? No
Order reference number
Title of your thesis/dissertation Synthesis Characterization and Properties of Coordination Polymers and Low Band Gap Polymers for use as Renewable Materials
Expected completion date May 2011
Estimated size (number of pages) 200
Elsevier VAT number GB 494 6272 12
Permissions price 0.00 USD
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Total 0.00 USD
250 Terms and Conditions
INTRODUCTION
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“Reprinted from Publication title, Vol /edition number, Author(s), Title of article / title of chapter, Pages No., Copyright (Year), with permission from Elsevier [OR APPLICABLE SOCIETY COPYRIGHT OWNER].” Also Lancet special credit - “Reprinted from The Lancet, Vol. number, Author(s), Title of article, Pages No., Copyright (Year), with permission from Elsevier.”
4. Reproduction of this material is confined to the purpose and/or media for which permission is hereby given.
5. Altering/Modifying Material: Not Permitted. However figures and illustrations may be altered/adapted minimally to serve your work. Any other abbreviations, additions, deletions and/or any other alterations shall be made only with prior written authorization of Elsevier Ltd. (Please contact Elsevier at [email protected])
6. If the permission fee for the requested use of our material is waived in this instance, please be advised that your future requests for Elsevier materials may attract a fee.
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251 8. License Contingent Upon Payment: While you may exercise the rights licensed immediately upon issuance of the license at the end of the licensing process for the transaction, provided that you have disclosed complete and accurate details of your proposed use, no license is finally effective unless and until full payment is received from you (either by publisher or by CCC) as provided in CCC's Billing and Payment terms and conditions. If full payment is not received on a timely basis, then any license preliminarily granted shall be deemed automatically revoked and shall be void as if never granted. Further, in the event that you breach any of these terms and conditions or any of CCC's Billing and Payment terms and conditions, the license is automatically revoked and shall be void as if never granted. Use of materials as described in a revoked license, as well as any use of the materials beyond the scope of an unrevoked license, may constitute copyright infringement and publisher reserves the right to take any and all action to protect its copyright in the materials.
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10. Indemnity: You hereby indemnify and agree to hold harmless publisher and CCC, and their respective officers, directors, employees and agents, from and against any and all claims arising out of your use of the licensed material other than as specifically authorized pursuant to this license.
11. No Transfer of License: This license is personal to you and may not be sublicensed, assigned, or transferred by you to any other person without publisher's written permission.
12. No Amendment Except in Writing: This license may not be amended except in a writing signed by both parties (or, in the case of publisher, by CCC on publisher's behalf).
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14. Revocation: Elsevier or Copyright Clearance Center may deny the permissions described in this License at their sole discretion, for any reason or no reason, with a full refund payable to you. Notice of such denial will be made using the contact information provided by you. Failure to receive such notice will not alter or invalidate the denial. In no event will Elsevier or Copyright Clearance Center be responsible or liable for any costs, expenses or damage incurred by you as a result of a denial of your permission request, other than a refund of the amount(s) paid by you to Elsevier and/or Copyright Clearance Center for denied permissions.
252 LIMITED LICENSE
The following terms and conditions apply only to specific license types:
15. Translation: This permission is granted for non-exclusive world English rights only unless your license was granted for translation rights. If you licensed translation rights you may only translate this content into the languages you requested. A professional translator must perform all translations and reproduce the content word for word preserving the integrity of the article. If this license is to re-use 1 or 2 figures then permission is granted for non-exclusive world rights in all languages.
16. Website: The following terms and conditions apply to electronic reserve and author websites: Electronic reserve: If licensed material is to be posted to website, the web site is to be password-protected and made available only to bona fide students registered on a relevant course if: This license was made in connection with a course, This permission is granted for 1 year only. You may obtain a license for future website posting, All content posted to the web site must maintain the copyright information line on the bottom of each image, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx or the Elsevier homepage for books at http://www.elsevier.com , and Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
17. Author website for journals with the following additional clauses:
All content posted to the web site must maintain the copyright information line on the bottom of each image, and he permission granted is limited to the personal version of your paper. You are not allowed to download and post the published electronic version of your article (whether PDF or HTML, proof or final version), nor may you scan the printed edition to create an electronic version, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx , As part of our normal production process, you will receive an e-mail notice when your article appears on Elsevier’s online service ScienceDirect (www.sciencedirect.com). That e-mail will include the article’s Digital Object Identifier (DOI). This number provides the electronic link to the published article and should be included in the posting of your personal version. We ask that you wait until you receive this e-mail and have the DOI to do any posting. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
253 18. Author website for books with the following additional clauses: Authors are permitted to place a brief summary of their work online only. A hyper-text must be included to the Elsevier homepage at http://www.elsevier.com
All content posted to the web site must maintain the copyright information line on the bottom of each image You are not allowed to download and post the published electronic version of your chapter, nor may you scan the printed edition to create an electronic version. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu.
19. Website (regular and for author): A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx. or for books to the Elsevier homepage at http://www.elsevier.com
20. Thesis/Dissertation: If your license is for use in a thesis/dissertation your thesis may be submitted to your institution in either print or electronic form. Should your thesis be published commercially, please reapply for permission. These requirements include permission for the Library and Archives of Canada to supply single copies, on demand, of the complete thesis and include permission for UMI to supply single copies, on demand, of the complete thesis. Should your thesis be published commercially, please reapply for permission.
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255 SCHOLASTIC VITA
Christopher M. MacNeill
Born: May 28, 1983, Boston, MA, USA
Education:
May 2011 Ph.D. Chemistry Wake Forest University, Winston-Salem, NC
Dissertation: Synthesis, Characterization and Properties of Coordination- and Low Band-Gap Polymers for Potential Catalytic and Photovoltaic Applications Advisor: Dr. Ronald E. Noftle
August 2006 M.S. Chemistry Sacred Heart University, Fairfield, CT Magna Cum Laude
Dissertation: Synthesis, Charaterization and FT-NMR solvent effect studies on Diamagnetic Complexes of Multidentate Heterocyclic Ligands.
May 2005 B.S. Chemistry Sacred Heart University, Fairfield, CT Magna Cum Laude
Academic Experience:
2009-2010 Graduate Research Assistant Department of Chemistry, Wake Forest University
2006-2011 Graduate Teaching Assistant Department of Chemistry, Wake Forest University
Chemical Analysis I Spring 2011 Materials Chemistry I Spring 2009 Inorganic Chemistry I Fall 2010 College Chemistry I (3) Fall 2006-2008 Organic Chemistry I Spring 2007 College Chemistry II Spring 2008
256
2004-2006 Undergraduate Research Assistant Department of Chemistry, Sacred Heart University
Professional Experience:
2005-2006 Research and Development Intern Unilever Home and Person Care, Trumbull, CT
Honors and Awards:
2007-2009 Wake Forest University Graduate Student Travel Award 2007, 2010 International Center for Materials Research Travel Award 2005-2006 Gold Medal of Excellence in Chemistry, Sacred Heart University
Publications:
“Variation of the side chain branch position leads to vastly improved molecular weight and OPV performance in 4,8-dialkoxybenzo[1,2-b:4,5-b’]dithiophene/2,1,3- benzothiadiazole copolymers.” R. C. Coffin, C. M. MacNeill, E. D. Peterson, J. W. Ward, J. W. Owen, C. A. McLellan, G. M. Smith, R. E. Noftle, O. D. Jurchescu, D. L. Carroll. J. Nanotech. 2011, accepted
“A Soluble High Molecular Weight Copolymer of Benzo[1,2-b:4,5-b’]dithiophene and Benzoxadiazole for Efficient Organic Photovoltaics.” Nie, W.; MacNeill, C.M.; Li, Y.; Noftle, R.E.; Carroll, D.L.; Coffin, R.C. Macro. Rapid Comm. 2011, submitted
“A Cyclopentadithiophene/Thienopyrroledione-based Donor-Acceptor Copolymer for Organic Solar Cells.” MacNeill, C.M.; Peterson, E.D.; Noftle, R.E.; Carroll, D.L.; Coffin, R.C. Synth. Met. 2011, in press, DOI: 10.1016/j.synthmet.2011.02.010.
“Synthesis, Crystal Structure and Properties of Novel Isostructural Two-Dimensional Lanthanide-Based Coordination Polymers with 2,3,5,6-Tetrafluoro-1,4- benzenedicarboxylic acid.” MacNeill, C.M.; Day, C.S.; Marts, A..; Lachgar, A.; Noftle, R.E. Inorg. Chim. Acta. 2011, 365, 196.
“Solvothermal and Reflux Syntheses, Crystal Structure and Properties of Lanthanide- Thiophenedicarboxylate-Based Metal Organic Frameworks.” MacNeill, C.M.; Day, C.S.; Gamboa, S.A.; Lachgar, A.; Noftle, R.E. J. Chem. Cryst. 2010, 40, 222.
“Synthesis, structure, and electrochemistry of N-(3-thenoyl)fluorosulfonimide and bis(2-thienoic)imide. Preparation of polymers containing the fluorosulfonimide group.” MacNeill, C.M.; Dai, J.; Howell, S.J.; Day, C.S.; Lazar, S.; Noftle, R.E. Synthetic Metals. 2009, 159, 1628.
257 “Bis(µ-dithieno[3,2-b:2',3'-d]thiophene-2,6-dicarboxylato-κ2O2:O6)bis[bis(1,10- phenanthroline-κ2N,N')cobalt(II)]dimethylformamide disolvate.” MacNeill, C.M.; Day, C.S.; Noftle, R.E. Acta Cryst., Sec. E. Cryst. Str. Rep. 2009, e65, m486.
Conference Presentations:
“Synthesis, Characterization and Photovoltaic Properties of a Series of Benzo[1,2- b:4,5-b’]dithiophene-based Conjugated Polymers for Solar Cell Applications.” Christopher M. MacNeill, Robert C. Coffin, Eric Peterson, David L. Carroll and Ronald E. Noftle; 2010 MRS Fall National Meeting, Boston, MA, United States, November 29-December 3, 2010.
“A Side Chain Variation Study on a Series of Benzo[1,2-b:4,5-b’]dithiophene-Based Conjugated Polymers for Solar Cell Applications.” Christopher M. MacNeill, Robert C. Coffin, Eric Peterson, Huihui Huang, David L.Carroll and Ronald E. Noftle. ICMR Summer School on Preparative Strategies in Solid State and Materials Chemistry, University of California at Santa Barbara, Santa Barbara, CA August 8- 21, 2010.
“Fluorine as a Substituent in Conducting- and Coordination Polymers.” Christopher M. MacNeill, R. Eric McAnally, Abdessedek Lachgar, Ronald E. Noftle, Jian Dai, Cynthia S. Day. Department of Chemistry, Wake Forest University, Winston-Salem, NC 27106, USA. Joint 65th Northwest and 22nd Rocky Mountain Regional Meeting of the American Chemical Society, Pullman, WA, United States, June 20-23, 2010.
“Catalytic Properties of Novel Lanthanide-Based Metal-Organic Frameworks Incorporating An Acidic Linker.” Christopher M. MacNeill, Cynthia S. Day, Amy Marts, Ronald E. Noftle. Department of Chemistry. Wake Forest University, Winston-Salem, NC 27106, USA. 61st Southeast Regional Meeting of the American Chemical Society, San Juan, Puerto Rico, October 21-24, 2009.
“A Novel Synthesis of PTB for Application in Highly Efficient Solar Cells.” Chanitpa Khantha. Christopher M. MacNeill, Ronald E. Noftle, S. Phanichphant, David L. Carroll. Nanoscience Research Laboratory, Department of Chemistry, Chiang Mai University, Thailand. Department of Chemistry, Wake Forest University, Winston-Salem, NC 27106, USA. Center for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, USA. Nanoconference. Bridger Field House, Winston-Salem, NC October 19, 2009.
“A Two-Dimensional Metal-Organic Framework Incorporating Lanthanides and 2,3,5,6-Tetrafluoro-1,4-benzoic acid.” Christopher M. MacNeill, Cynthia S. Day and Ronald E. Noftle. Department of Chemistry, Wake Forest University, Winston- Salem, NC 27106, USA. 60th Southeast Regional Meeting of the American Chemical Society, Nashville, TN, November 12-15, 2008.
258 “Thiophene Dicarboxylates in the Synthesis of Metal-Organic Framework Materials.” Christopher M. MacNeill, Cynthia S. Day, Sergio A. Gamboa, Abdessadek Lachgar, Ronald E. Noftle. Department of Chemistry, Wake Forest University, Winston-Salem, NC 27106, USA. 4th meeting of the Materials Research Society of Africa. Dar Es Salaam, Tanzania, December 10-14, 2007
“Thiophene Dicarboxylates in the Synthesis of Metal-Organic Framework Materials.” Christopher M. MacNeill, Cynthia S. Day, Sergio A. Gamboa, Melissa Donaldson, Abdessadek Lachgar, Ronald E. Noftle. Department of Chemistry, Wake Forest University, Winston-Salem, NC 27106, USA. 59th Southeast Regional Meeting of the American Chemical Society, Greenville, SC, October 24-27, 2007.
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