INFORMATION TO USERS
This manus&ipt has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.
The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality iilustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.
In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.
Oversize materials (e g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps.
Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order.
ProQuest Information and Learning 300 North Zeeb Road, Arm Arbor, Ml 48106-1346 USA 800-521-0600
UMÏ
PARTI SYNTHESES AND CHARACTERIZATION OF HYDROGEN-BRIDGED LANTHANIDE(n)-BORON COMPLEXES
PARTE SYNTHESES AND CHARACTERIZATION OF CYANIDE-BRIDGED LANTHANn)E(IH)-PALLADIUM COMPLEXES
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate
School of The Ohio State University
By
Soyoung Lim, B. S.
*****
The Ohio State University 2001
Dissertation Committee: ! Approved Approvea ^ny Dr. Sheldon G. Shore, Advisor Dr. James A. Cowan ______^ l JFJAd^sor . Dr. Claudia Tutro Department of Chemistry UMI Number 3022525
UMI’
UMI Microform 3022525 Copyright 2001 by Bell & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code.
Bell & Howell Information and teaming Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT
Parti
Hydrogen-bridged lanthanide(II)-boron complexes were synthesized and characterized. (CH3CN)%Ln[B3Hg]2 was prepared by the metathesis reaction between
(NH3)xLnCl2, (Ln = Yb, Eu) and KP3H8] in liquid NH3 and subsequent displacement of
NH3 with CH3CN. The preliminary structure of (CH3CN)4Yb[B3Hg]2, 1, is interesting since the two [B3Hg]' anions have different bonding modes. From NMR spectroscopic studies, the [B3Hg]* anion was determined to be fluxional even at 213 K.
[Yb(CH3CN)g][Bi2Hi2], 2, and (CH3CN)6Yb[(p-H)2BnHu], 3, crystallized from the
saturated CH3CN solution of (CH3CN)4Yb[B3Hg]2, 1. The oxidized species,
[Eu(NH3)6(CH3CN)3][B3Hg]3, 7, was obtained from an CH3CN solution of
(CH3CN)xEu[B3Hg]2,6. The organohydroborate derivatives, (THF)4Yb[(p-H)2BCgHi4]2.
8, and [(THF)4K]2[Eu{(p-H)2BCgHi4}4], 10, were synthesized by the metathesis reaction
of (THF)xLnCl2, (Ln = Yb, Eu) with K[H2BCgHt4] in THF at room temperature. 2 and 7
are solvent-separated ion-pairs. 3 is the only structurally characterized metallaborane
containing 11 boron atoms. For 3,8 and 10, the anions are coordinated to the Ln(ll) ions
through three-center two-electron B-H-Ln bonds. Bridging hydride ion can be abstracted
from the reaction of 8 with B(C6F$)3. For 10, unique agostic H-Eu and H-K interactions
ii were observed. Crystal data for 2: monoclinic, Cc, a = 14.2260(10) A, 6 = 13.1350(10)
A, c = 16.4780(10) A,/? = 90,000(30)®, Z = 4. Crystal data for 3: monoclinic, P 2i/c, a =
9.5097(10) A, 6 = 14.1574(10) A, c = 22.8192(10) A ,^ = 97.321(10)®, Z = 4. Crystal data for 7: hexagonal, P6^/m, a = b = 14.2797(10) A, c = 8.8740(10) k,a=fi = 90®, y =
120®, Z = 1. Crystal data for 8 : triclinic, PI, a = 9.8616(10) A, 6 = 10.2266(10) A, c =
10.4760(10) A, a = 69.873(10)®, p = 76.629(10)®, y = 66.116(10)®, Z = 2. Crystal data for
10: tetragonal, P 42/nmc, a = b = 13.4390(19) A, c = 20.421(4) A,a=p = y = 90®, Z = 4.
Part II
Cyanide-bridged lanthanide(III)-palladium complexes were prepared and characterized. The metathesis reaction between LnCb, (Ln = La, Gd) and K 2[Pd(CN) 4]
with a 2 to 3 molar ratio in DMF at room temperature yielded two different types of one
dimensional polymeric arrays: the double-strand Type B array,
{(DMF)ioGd 2[Pd(CN) 4]3}-, 11, and the zigzag chain Type C array containing
“diamond”-shaped metal cores, {(DMF)t 2La2[Pd(CN) 4]3}-, 12. Meanwhile, a zigzag
single-strand array, {(DMF)sLn[Pd(CN) 4]Cl}-, (Ln = La, 13; Gd, 14) were synthesized
by the metathesis reaction between LnCb and K 2[Pd(CN) 4] with a 1 to 1 molar ratio in
DMF. Crystal data for 11; triclinic, P\,a = 9.2940(10) A, 6 = 11.1879(10) A, c =
16.4544(10) A, a = 81.462(10)“,^ = 76.945(10)®, y = 83.230(10)®, Z= 1. Crystal data for
12: triclinic, P\,a= 11.4762(10) A, 6 = 12.5675(10) A, c = 13.9467(10) A, a =
97.464(10)®, p = 109.508(10)®, y = 102.113(10)®, Z = l. Crystal data for 13: monoclinic,
P2i/c, a = 7.5828(10) A, 6 = 22.1789(10) A,c = 17.8413(10) K P = 99.070(10)®, Z = 4.
Crystal data for 14: monoclinic, PZi/n, a = 7.755(3) A, 6 = 17.810(7) A, c = 21.576(6) A,
^ = 92.72(3)®, Z = 4.
iii Dedicated to my parents, my brother Cheho and my sister Jayoung
IV ACKNOWLEDGMENTS
I would like to sincerely thank Dr. Sheldon G. Shore for his guidance, enormous patience, encouragement, knowledge and support.
I am deeply grateful to Dr. Shore’s group. To Drs. Shengming Liu, Jianping Liu,
Edward A. Meyers and Bin Du for solving my crystal structures and teaching me crystallography. To Drs. Fu Chen Liu and Jianping Liu for helping me start research in the group. To Mr. Roman Kultyshev for helping me with various temperature NMR experiments. Especially to Ms. Christine E. Plenik for her careful prooAeading. I would like to express my special gratitude to all the group members for their help, encouragement and cherished friendship.
I would like to extend sincere thanks to Dr. limit S. Ozkan and her group for letting me be introduced in the area of catalysis. I also need to thank Dr. Andrew
Wojcicki and his group for guidance and help during my earlier graduate years. VITA
November 6,1970 ...... Bom-Taegu, Korea
1993 ...... B. S. Chemistry Education
Kyungpook National University, Taegu, Korea
1994 -1999 ...... Graduate Teaching Associate
The Ohio State University
1999 - present ...... Graduate Research Associate
The Ohio State University
PUBLICATIONS
1. Sung-Ho Chun, Edward A. Meyers, Fu-Chen Liu, Soyoung Lim, Sheldon G. Shore.
"Systematic syntheses of [Hg{M(CO) 4}2]^ [Hg{M(C 0 )4}]* (M = Fe, Ru, Os), and structures of [Hg{M(CO)4}2]^‘ (M = Ru, Os)" J. Organomet. Chem. 1998, 563,23.
FIELDS OF STUDY
Major Field: Chemistry
VI TABLE OF CONTENTS
Page
Abstract...... ii
Dedication ...... iv
Acknowledgments...... v
Vita...... vi
List of Tables...... ix
List of Figures...... xi
List of Schemes ...... xv
Chapters:
Parti
1. Introduction...... l 1.1. The lanthanides ...... 1 1.2. Divalent lanthanide chemistry ...... 3 1.3. The lanthanide borides ...... 7 Statement of Problems...... 15
2. Results and Discussion...... 17 2.1. (CH3CN)4Yb[B3H8]2,1 ...... 17 2.2. [Yb(CH3CN)8][Bi2H,2].2 ...... 21 2.3. (CH3CN)6Yb[(p-H)2BiiHiil,3 ...... 30 2.4. (C5H5N)xYb[B3H8]2,4 ...... 39 2.5. (THF)xYb[B3H8]2,5 ...... 40 2.6. The formation of clusters...... 46 2.7. (CH3CN)xEu[B3H8 ]2 ,6 ...... 48 2.8. [E u(NH3)6(CH3CN)3][B3H8]3, 7 ...... 49 2.9. (THF) 4Yb[(p-H) 2BC8Hu]2 ,8 ...... 56
vu 2.10. Hydride ion abstraction reaction from (THF)4Yb[(ji-H)2BC8Hi4]2.8 with B(C6F;)3 ...... 57 2.11. [(THF)4K]2[Eu{(h-H)2BC8Hm}4], 10 ...... 69
3. Experimental ...... 76 3.1. Apparatus ...... 76 3.2. Solvents and Reagents ...... 81 3.3. Preparation of Starting Materials ...... 83 3.4. Reactions...... 84
Part H
4. Introduction...... 91 4.1. Cyanide-bridged lanthanide-transition metal complexes ...... 91 4.2. Classification of non-aqueous cyanide-bridged lanthanide(ni)-transition metal complexes ...... 94 Statement of Problems...... Ill
5. Results and Discussion...... 113 5.1. Synthesis and infrared spectral studies of {(DMF)ioGd2[Pd(CN)4l3}«, 11 ...... 113 5.2. Molecular structure of {(DMF)ioGd2[Pd(CN) 4]3}», 11...... 114 5.3. Synthesis and infrared spectral studies of {(DMF),2La2[Pd(CN) 4]3}«, 1 2 ...... 126 5.4. Molecular structure of {(DMF)uLa2[Pd(CN) 4]3}oo, 12...... 127 5.5. Syntheses and infrared spectral studies of {(DMF)5Ln[Pd(CN) 4]Cl}«, (Ln = La, 13; Gd, 14)...... 137 5.6. Molecular structures of ((DMF)5Ln[Pd(CN) 4]Cl}oo, (Ln = La, 13; Gd, 14) ...... 140
6. Experimental ...... 152 6.1. Apparatus ...... 152 6.2. Solvents and Reagents ...... 152 6.3. Preparation of Starting Materials ...... 153 6.4. Reactions...... 153
List of References...... 157
vm LIST OF TABLES
Table Page
1. Crystallographic data for [Yb(CH 3CN)8][Bi2Hi2], 2 ...... 24
2. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A' X 10^) for [Yb(CH3CN)8][Bi2Hi2], 2 ...... 25
3. Bond lengths (A) and angles (“) for [Yb(CH 3CN)8][Bi2Hi2], 2 ...... 26
4. Crystallographic data for (CH 3CN)6Yb[(p-H) 2BiiHii], 3 ...... 33
5. Atomic coordinates ( x 10"*) and equivalent isotropic displacement parameters (A^ X 10^) for (CH3CN)6Yb[(p-H) 2BiiH„], 3 ...... 34
6. Bond lengths (A) and angles (®) for (CH 3CN)6Yb[(p-H) 2BuHi i], 3..... 35
7. Crystallographic data for [Eu(NH 3)6(CH3CN)3][B3H8 ]3, 7 ...... 52
8. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A^ X 10^) for [Eu(NH3)6(CH3CN)3][B3H8]3, 7 ...... 53
9. Bond lengths (A) and angles O for [Eu(NH 3)6(CH3CN)3][B3H8]3, 7 ...... 54
10. Crystallographic data for(THF)4Yb[(p-H)2BC8Hi4]2.8 ...... 60
11. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ X 10^) for (THF)4Yb[(p-H)2BC8Hi4]2,8 ...... 61
12. Bond lengths (A) and angles O for (THF)4Yb[(p-H)2BC8Hi4]2,8 ...... 63
13. Crystallographic data for [(THF) 4K]2[Eu{(p-H)2BC8Hi4}4], 10...... 71
14. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A^ X 10^) for [(THF)4K]2[Eu{([i.H)2BC8Ht4}4]. 10 ...... 72
IX 15. Bond lengths (A) and angles O for [(THF) 4K]2[Eu{(^-H)2BC8Hi4}4], 1 0 ...... 73
16. Crystallographic data for {(DMF)ioGd 2[Pd(CN) 4]3}», 11...... 121
17. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A^x 10^) for {(DMF),oGd 2[Pd(CN) 4]3}«. 11...... 122
18. Selected bond lengths (A) and angles O for {(DMF)ioGd 2[Pd(CN) 4]3}oo, 11..... 124
19. Crystallographic data for {(DMF)i 2La2[Pd(CN) 4]3}», 12...... 132
20. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^x 10^) for {(DMF)uU2[Pd(CN) 4]3}«, 1 2 ...... 133
21. Selected bond lengths (A) and angles (®) for {(DMF)i 2La2[Pd(CN) 4]3}«. 1 2 ...... 135
22. Crystallographic data for {(DMF) 5La[Pd(CN) 4]CI}«, 13...... 144
23. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ X 10^) for {(DMF)5La[Pd(CN) 4]CI}«, 13...... 145
24. Selected bond lengths (A) and angles (“) for {(DMF) 5La[Pd(CN) 4]CI}oo, 13...... 146
25. Crystallographic data for {(DMF) 5Gd[Pd(CN) 4]CI}oo, 14...... 148
26. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A^x 10^) for {(DMF)5Gd[Pd(CN) 4]CI}cc, 14...... 149
27. Selected bond lengths (A) and angles O for {(DMF) 5Gd[Pd(CN) 4]CI}», 14...... 150 LIST OF FIGURES
Figure Page
1. Perspective diagram of the Cp 2Yb(DME) molecule...... 7
2. Molecular structure of [Yb(ii^-C5H4SiMe3)2(THF)2] ...... 7
3. Molecular structure of (Me;C;)2Sm(THF)2 ...... 7
4. Molecular structure of [(MesC5)2Sm(p- 0 (THF)2]2...... 7
5. Molecular structure of (Me5Cs)2Sm ...... 8
6. Molecular structure of (ii®-CgH8)Yb(C5H5N) 3 ...... 8
7. Molecular structure of Yb(C2B9Hi iXDMF)4 ...... 9
8 . Molecular structure of (CH3CN)6Yb[(p-H) 2BioHi2] ...... 11
9. Molecular structure of (CH3CN)4Yb[(p-H) 3BH]2 ...... 12
10. Molecular structure of (CsH5N)4Yb[BH4]2...... 12
11. Cubic MBs showing (a) boron octahedra, and (b) coordination around each metal atom ...... 14
12. Preliminary molecular structure of (CH3CN)4Yb[B3Hg] 2, 1...... 18
13. 128 MHz ‘ ‘B NMR spectra of (CH 3CN)4Yb[B3H8]2, 1, in CD3CN ...... 19
14. 400 MHz ‘H NMR spectra of (CH 3CN)4Yb[B3H8]2, 1, in CD3CN ...... 20
15. Molecular structure of [Yb(CH3CN)8]P i2Hi2], 2 ...... 23
16. Molecular structure of (CH3CN)6Yb[(p-H) 2BuHu], 3...... 31
xi 17. 160 MHz " b NMR spectra of crystals of (CH3CN)6Yb[(p-H)2B nHn], 3 inrfs-THF...... 32
18 . Variable temperature (233 K to 353 K) 160 MHz "B NMR spectra of (C5H5N)xYb[B3H8]2, 4, in CjDsN...... 41
19 . Variable-temperature (233 K to 353 K) 500 MHz ^H NMR spectra of (CsH5N)xYb[B3H8]2. 4, in C5D5N...... 42
20. 160 MHz ‘ ‘B NMR spectra of crystals of (THF)xYb[B3H8]2, 5, in
21. 500 MHz ‘H NMR spectra of crystals of (THF)xYb[B3H8]2, 5, inrfa-THFat213K ...... 45
22. 80 MHz ‘ *B NMR spectra of an CH3CN solution of (CH3CN)4Yb[B3H8]2, 1, after beating at different temperatures ...... 47
23. (a) Molecular structure of [Eu(NH3)6(CH3CN)3]^^ and (b) molecular structure of [B3H8]‘...... 50
24. 80 MHz ‘ ‘B {‘H} NMR spectrum of[Eu(NH3)«(CH3CN)3][B3H8]3,7, inCHsCN...... 51
25. Molecular structure of (THF)4Yb[(p-H)2BC8Hul2,8...... 58
26. 80 MHz ‘ 'B NMR spectra of (THF)4Yb[(p-H)2BC8Hi4]2,8, in rf«-THF ...... 59
27. 80 MHz * B NMR specta of the reaction mixture containing [(THF)xYb ((p- H)2BC8H,4}f[HB(C6F5)3r, 9 ...... 68
28 . Molecular structure of [(THF)4K]2[Eu{(p-H)2BC8Hi4}4],10 ...... 70
29 . (a) View of the hexagonal LaFe(CN)6*5H20 structure and (b) projection of the oithorhombic SmFe(CN)6«4H20 ...... 93
30. Stereoview of Fe(CN)6^ octahedra arrangement of LaKFe(CN)6'4H20 ...... 93
31. Molecular structure of a portion of the one-dimensional “ladder” in {(DMF)4Eu[Ni(CN)4]}«...... 95
32. Molecular structures of a portion of the one-dimensional arrays: (a) {(DMF)ioEr2[Ni(CN)4]3}«and(b) {(DMF)ioYb2(Pd(CN)4]3}«...... 99
XU 33. Coordination geometry around the lanthanide ions in (a) {(DMF)ioEr2[Ni(CN)4]3}=oand(b) {(DMF)ioYb2[Pd(CN)4]3}«...... 99
34. The conversion of Sm-Ni complex from structural type A to type B ...... 100
35. Solid-state infrared spectra of (a) type A complexes and (b) type B complexes... 102
36. Solution infrared spectra of (a) type A complexes and (b) type B complexes .....102
37. Molecular structure of {(DMF)i2Ce2[Ni(CN)4 ] 3 ...... 104
38. Coordination geometry around the Ce(III) ion in {(DMF)i 2Ce2[Ni(CN)4]3}»....104
39. (a) Solid-state infrared spectra and (b) solution infrared spectra of type C complexes ...... 106
40. Molecular structures of a portion of the one-dimensional arrays: (a) {(DMF)5Sm[Ni(CN)4]Cl}«and(b) {(DMF)4Yb[Ni(CN)4]Cl}«...... 108
41. Coordination geometry around the lanthanide ions in (a) {(DMF)5Sm[Ni(CN)4]Cl}«and(b) {(DMF)4Yb[Ni(CN)4]Cl}co...... 108
42. (a) Solid-state infrared spectra and (b) solution infrared spectra of complexes {(DMF)sSm[Ni(CN)4]Cl}«and {(DMA)4Yb[Ni(CN)4]Cl}«...... 110
43. (a) Solid-state infrared spectrum and (b) solution infrared spectrum of {(DMF),oGd 2[Pd(CN) 4]3}«, 11...... 115
44. Molecular structure of {(DMF)ioGd2[Pd(CN) 4]3}«. H ...... 117
45. Square antiprismatic geometry around the Gd(III) ion in {(DMF),oGd 2[Pd(CN) 4]3}«, 11...... 118
46. Possible rotational disorder of the DMF ligands (a) around the Ln-0 axis and (b) around the Ln-0 N axis ...... 120
47. (a) Solid-state infrared spectrum and (b) solution infrared spectrum of {(DMF)i2La2[Pd(CN) 4]3}-. 1 2 ...... 128
xm 48. Molecular structure of a portion of the one-dimensional array {(DMF),2La2[Pd(CN)4]3}c., 12 ...... 129
49. Monocapped square antiprismatic geometry around the La(III) ion in {(DMF)i2La2[Pd(CN) 4]3}«, 12...... 131
50. (a) Solid-state infirared spectra and (b) solution infrared spectra of {(DMF)5Ln[Pd(CN) 4]Cl}oo, (Ln = La, 13; Gd, 14) ...... 139
51. Molecular structures of a portion of the one-dimensional arrays; (a) {(DMF)5La[Pd(CN) 4]Cl}«, 13 and (b) {(DMF)5Gd[Pd(CN) 4]Cl}«, 14...... 141
52. Square antiprismatic geometry around (a) the La(IU) ion in {(DMF)5La[Pd(CN)4]Cl}«, 13 and (b) the Gd(III) ion in {(DMF)5Gd[Pd(CN) 4]Cl}», 14...... 143
XIV LIST OF SCHEMES
Page
Scheme
1. The ways in which repeating units combine to generate two different but related structural type A and B ...... 97
2. Different crystallization pattern of Ln-Ni complex and Ln-Pd complex ...... 100
XV CHAPTER 1
INTRODUCTION
I. The lanthanides
The lanthanides (Ce-Lu, atomic numbers 58-71) are composed of the fourteen elements in which electrons are filled consecutively in the seven 4f orbitals. Lanthanum
(La, atomic number, 57) and yttrium (Y, atomic number 39) are also included in this series since they are like the lanthanides in many respects. The name, lanthanides is derived from the fact that chemical and physical properties of the elements of this series are very similar to those of lanthanum.' The official lUPAC term is lanthanoid because the -ide suffix is used for naming anions. The lanthanides are also called the rare earth elements because they were discovered as mixtures of their oxide forms from two minerals.^ However, the rare earth elements are really not rare since some of them, e.g. yttrium, are more abundant than cadmium or mercury in nature.^
The pure elements of the lanthanides were not readily available until late 1940s since their coexistence in nature and remarkably similar physical and chemical properties made separation of the lanthanides in a pure form very difficult.^
I The feature of 4f valence orbitals makes the lanthanides unique compared to other classes of elements in the periodic table. The 4f valence orbitals do not extend significantly beyond the filled Ss^5p‘ orbitals of the xenon inert gas core.'* Thus, a trivalent lanthanide ion with a [Xe]4f electronic configuration, looks like a noble gas core with a tripositive charge, resulting in a single thermodynamically stable oxidation state +3 throughout the series. Only few have stable nontrivalent oxidation states under normal reaction conditions, e.g., Ce% Sm^% Eu^* and Therefore, oxidative addition and reductive elimination reactions, common in transition metal chemistry, do not occur.^ In addition, this small radial extension of 4f valence orbitals leads to similarity in chemistry of the lanthanides. For example, when oxidation states and anions are identical, complexes containing the lanthanides display isomorphous crystal structures and similar reactivities.^ The limited radial extension of 4f valence orbitals also contributes to the little orbital interaction between the lanthanide and ligands, resulting in little ligand stabilization energy. The chemistry of the lanthanides is thus expected to be ionic and similar to that of alkali or alkaline earth metals.^ For example, with a given 4 f electronic configuration, ligands have little effect on the magnetic moments and the optical spectrum of a lanthanide ion.^ Moreover, the interaction with ligands such as carbonyl, hydrogen, phosphine, unsaturated hydrocarbon, which leads to rich transition metal coordination chemistry, is not expected.^ Another consequence of the restricted radial extension of the 4f valence orbitals is the well-known lanthanide contraction. The sizes of ions or atoms of the lanthanides decrease uniformly fix>m cerium to lutetium due to the imperfect shielding of the 4f valence electrons fi^m the nuclear charge.^ This lanthanide contraction makes the lanthanides very electropositive.
2 Hence, the lanthanides are considered as hard Lewis acids and prefer to coordinate to hard Lewis bases containing fluorine, oxygen and nitrogen atom donors.’
The other important characteristic of the lanthanides is their considerably large size compared to transition metals. Lower coordination numbers 3 to 7 seem to be uncommon and directly associated to steric effects. The coordination numbers of 8 to 12 are typical ones for the lanthanides. The coordination numbers of 8 and 9 are preferred.” Therefore, stable and bulky anions such as CjMcj' and CgHg*' are often employed to isolate discrete lanthanide complexes.
The lanthanides(U) are extremely air- and moisture-sensitive requiring the use of vacuum line or Schlenk line and dry box techniques. In addition, most of the lanthanides are paramagnetic. Thus, NMR spectroscopy is usually not accessible for characterization of the lanthanide complexes. On the other hand, the paramagnetic nature of the lanthanide ions allows them to be applied as NMR shift reagents."
However, the unique characteristics of the lanthanides also give unusual compounds with unprecedented structures and magnificent reactivities. Especially, the potential of application of lanthanide compounds for materials synthesis has attracted much attention in recent years.'^ The chemistry of the lanthanides is one of the fast-developing research areas at the present time.
2. Divalent lanthanide chemistry
The existence of Ln(H) was not known until 1906 when the first compound containing a divalent lanthanide ion, SmCl;, was prepared by reduction of the trichloride with hydrogen, aluminum or ammonia at elevated temperatures.^
3 Even though all the lanthanides might exist in the divalent state in crystalline alkaline earth metal halide matrices," only Sm^\ and are readily accessible under normal reaction conditions. The stability of Eu^^ and Yb^^ comes from their 4f half-filled and 4 f ^ filled subshell electronic configurations.
Despite divalent lanthanide stoichiometry of many lanthanide binary compounds, not all of these compounds actually have W * ions. For example, the hydrides LnH;, some of the halides LnX% and the carbides LnCj are considered to have Ln^^ ions, metallic electrons and the anions H , X and C;^' and are formulated as W*(e )H%, Ln^*(e
)Xj or W*(e )C 2. This is supported by their metallic conduction properties due to the presence of metallic electrons in the conduction band.^
Standard reduction potentials in aqueous solution for the Ln^^-Ln^^ couple are reported to be -1.55 V for Sm, -0.43 V for Eu and -1.15V for Yb (vs. NHE).^ Thus, Sm^* is least stable and Eu^^ most stable toward oxidation. The ions in solution are usually more easily oxidized than the solid compounds. Yb^* (4f is diamagnetic and species containing Yb^* can be characterized by NMR. Species containing Sm^^ and Sm^* are also NMR-accessible although their magnetic moments are 3.4-3 .8 pg for Sm^* and 1.3-
1.9 P b (or Sm^*. However, Eu^% Eu^* and Yb^\ whose magnetic moments are 7.4-8.0,
3.4-4.2 and 4.2-4.9 pg, respectively are not NMR-accessible.^
Complexes containing divalent lanthanide ions display more intense color than complexes of trivalent lanthanides. The colors of the trivalent lanthanide complexes come fix)m Laporte-forbidden 4f-*4f transitions. Crystal field splitting is very small due to the small radial expansion of 4f valence orbitals. Consequently, colors are pale and vary little as the ligands are changed. In contrast, the colors of the divalent lanthanide 4 complexes are 6 om Laporte-allowed 4f-»Sd transitions. Thus, colors are vivid and varies as ligands are changed. For example, complexes containing Sm^^ show green or purple colors. The colors of species containing Eu^^ are usually yellow, orange or red.
Yb^'’ complexes can be yellow, red, blue, green or purple.*
Although many divalent organometallic lanthanide complexes were prepared, only a small number of structures have been reported. Like trivalent lanthanide complexes, stable and buUqr anions such as C$H/, QM e/ and their derivatives and additional solvent molecules are commonly used to satisfy the electrostatic and steric requirements of divalent lanthanide ions to give discrete complexes.* The coordination numbers of the divalent lanthanide ions in these discrete complexes are usually 7 to 10.*
The examples of the complexes containing solvated cyclopentadienyl ligands or mono substituted cyclopentadienyl ligands are (C;H;);Yb(DME),'* [(MeCjH 4)(THF)Yb(n-
MeC;HJ]n or [(MejSOCjHJjYbCTHF)!.'® The crystal structure of one example,
(CjHj)2Yb(DME) was reported by Deacon and Taylor, et al. and it is the first structure of an unsubstituted di-q^-cyclopentadienylytterbium(H) derivative (fig. 1). The ytterbium
ion is pseudo-tetrahedrally coordinated to two Cp ligands and a bidentate DME ligand.
Another example, [(Me^SOQH^JzYXTHF); was synthesized and structurally characterized by Lappert and Atwood, et al. The ytterbium ion is also pseudo-
tetrahedrally coordinated to two CgH/SiMe;) ligands and two THE ligands (fig. 2). The
examples of the complexes containing pentamethylcyclopentadienyl and solvent ligands
are (C #e,)2Yb(THF)4).SCH]CA," (QMe;)2Yb(NC^;)2," (C;Me;)zYb(THF)(NH3),"
(C5Me5)2Sm(THF)2,“ *^‘“ (C 5Me5)2Eu(OEt2),“ [(CsMes)(THF)2Eu(n-CCPh)]2^ and
[(CjMe5)Sm(n-IXTHF)2]2.*‘ The crystal structure of one example, (C;Me;) 2Sm(THF)2 is 5 shown in figure 3. The two Cp* rings are not parallel as in Cp\Fe, but are tilted. Each oxygen atom of the two THF molecules lie roughly in the plane bisecting the (ring centroid)-metal-(ring centroid angle). The methyl groups of the two Cp* rings are staggered with respect to each other. The crystal structure of the dimer, [(C;Me$)Sm(p- l)(THF)2]z is displayed in figure 4. The SmCp-QjSm’ unit is planar. The Cp' ring is on one side of the plane, and two THF molecules are on the other.
From desolvation and sublimation of (C;Me$)2Sm(THF)2, (CsMej)2Sm was prepared. Evans, et al. reported the crystal structure of this unusual complex. The coordination number of the Sm(U) ion is 6. In this coordinatively unsaturated solvent- free complex, a (ring centroid)-metal-(ring centroid) angle is 140.1°, not 180° (fig. 5).
From an electrostatic standpoint, it would be more stable for the two Cp* anions to be positioned as far as possible, as in the parallel arrangement in Cp ^Fe. The stability of this complex is unusual because it does not follow typical electrostatic and steric requirements.
Other bulky anion, C;H/ was also used to stabilize the divalent lanthanide ion. (q^-
C;H;)Yb(C;H;N)2*0.5(C;H;N) “ was prepared fix)m the reaction of ytterbium in liquid ammonia with cyclooctatetraene and structurally characterized by Wayda and Rogers, et al. The Yb(II) ion is eight-coordinate. The five electron pairs from the q^- cyclooctatetraenide ligand and three nitrogen atoms fiom the pyridine molecules occupy the coordination sphere around the Yb(II) ion (fig. 6).
There are also very interesting divalent organometallic complexes in which divalent lanthanides are bonded to boron via hydrogen bridges. Hawthorne et al. aw CO) cm C(4) X(9) cni can, OQ)
cm C02L toil 00)
C(13)
Figure 1. Perspective diagram of Figure 2. Molecular structure of the CpjYbCDME) molecule. [Yb(n'-CASiMe3MTHF)J.
C 7 '.lea C6< IC8 CI7 CS
Me]
)C3 CIS
Figures. Molecular structure of Figure 4. Molecular structure of (MeA)2Sm(THF)2. [(MeA)2Sm(p-I)(THF)j3. CM
Figure S. Molecular structure of (MejCj)2Sm.
Figure 6. Molecular structure of (ii*-CgHg)Yb(CjHsN)3 reported that the first ti^-boimd metallacarborane containing a divalent ion, the closo- lanthanacarborane, Yb(C 2B,Hn)(DMF)4,^^ (DMF = N, N’-dimethylformamide) was obtained by the reaction of ([^[nido-T.S-QBgHn) with Ybl; in THF and subsequent displacement of THF with DMF and crystallizaton. The divalent ytterbium ion is seven- coordinate with three electron pairs being donated by the q^-bound dicarbollide ligand and four oxygen atoms firom the DMF ligands (fig. 7). The structure would not suitably refine due to serious disorder of the DMF methyl carbon atoms. The bonding in this complex was largely considered ionic firom the comparable bond distances to those of analogous cyclopentadienyl compounds.
@ O x y g en O B H /C H
Figure 7. Molecular structure of YXCiBgHtJCDMF)^. Only the oxygen atoms of the coordinated DMF ligands are shown. White and Shore, et al. reported the first structurally characterized polyhedral boron hydride lanthanide complex in which a divalent lanthanide ion and boron are connected through bridging hydrogens, (CH 3CN)«Yb(p-H)2B,oH,2' 2CH3CN." “ This complex was prepared by the reduction of BioH ,4 with Yb in liquid NHj and consequent displacement of NHj with CHjCN and crystallization from CHjCN. The Yb(II) ion is eight-coordinate and is ligated to six nitrogen atoms of the CHjCN ligands and to two boron atoms of [B,oH,4]^' through two three-center two-electron B-H-Yb bridges (fig. 8 ).
All of the hydrogen atoms on the B,o cage were located from X-ray data. Solution
‘ ‘B NMR data of the crystal agreed well with the solid state structure. In addition, two ytterbium(n)bis(borohydride) complexes, (CHjCN) 4Yb[(p-H)jBH ]2 and
(C;H$N)4Yb[BH4]2' 2C;H;N, were also synthesized and structurally characterized by
White and Shore, et al.” In (CH 2CN)4Yb[(p-H)]BH] 2, each borohydride ligand is linked to the Yb(n) ion through three Yb-H-B bridges (fig. 9). All of the hydrogen atoms were located firom X-ray data. Four nitrogen atoms of the CHjCN ligands are also coordinated in a "seesaw '-configuration with respect to the Yb(II) ion. In
(C;H;N)4Yb[BH4]2*2C;H;N, the Yb(H) ion has an axially distorted octahedral coordination geometry with two borohydride ligands trans to each other (fig. 10). Four pyridines coordinate to the central Yb(II) ion with a "propeller shaff'-arrangement in the equatorial plane of the octahedron. Moreover, the complexes (CH]CN) 4Yb[(^-H)3BH]2 and (Π3CN)2Eu[B3Hg]2 were thermally decomposed to give lanthanide borides, YbB 4 and EuBg, respectively.
10 Figure 8. Molecular structure of (CH3CN)6Yb[(n-H)2B,oH,J.
II Figure 9. Molecular structure of (CHjCN)4Yb[(n-H)3BH]2
Figure 10. Molecular structure of (C;H;N)^Yb[BHj2.
12 3. The lanthanide bondes
The lanthanide borides have attracted so much attention because of their interesting structures, high thermal and chemical stabilities together with fascinating electrical and magnetic or superconductive properties/"'
Six types of the lanthanide borides are known. Those are LnB;, LnB^, LnzB,,
LnBg, LnB ,2 and LnBgg. The relatively large radii and more electropositive character of the lanthanide result in the boron-rich borides. On the other hand, the metal-rich borides are principally formed among the transition elemets of Groups V-VIII.^°
The fascinating physical properties of the lanthanide borides have been reported, for example, ErB^ and H 0 B4 (magnetic phase transition), YbB^, YbB,; and SmB,
(intermediate-valence state), CeB« (dense Kondo-like behavior), EuBg (ferromagnetic semiconductor), LaBg (thermoelectronic emitter) and YB, (superconductor).^'
Hexaborides crystallize with a cubic structure, having a three-dimensional boron network whose interlattice spaces are filled with metal atoms (Fig. 11). This skeleton promotes the thermal stability of hexaborides. For example, the melting point ofLaBg is 2230 °C, compared to the melting point of La metal, 920 °C. Hexaborides of the lanthanides have a very low work fimction which thus gives rise to high thermionic emission measurements. These combined characteristics make the lanthanide borides good candidates for electronic devices such as cathodes.”
EuBg and YbB« have pure +2 oxidation states among the lanthanide hexaborides and fimction as semiconductors.^'” SmBg has a mixture of +2 and +3 oxidation states and its electrical properties show intermediate character between semiconductor and metallic conductor. The other lanthanide hexaborides are metallic conductors and are
13 reported to have +3 oxidation states. It is interesting to note that EuB, is the only boride known for Eu. This is due to the particularly large size of Eu.^'
0 Mml #
(•)
Figure 11. Cubic MB, showing (a) boron octahedra, and (b) coordination around each metal atom.
14 Statement of Problems
The goal of this research is to synthesize hydrogen-bridged lanthanide(II)-boron complexes and to characterize these complexes with X-ray single crystal analysis, NMR and IR spectroscopies. These complexes are potential precursors to lanthanide borides.
Lanthanide borides have attracted much attention because of their interesting structures, high thermal and chemical stabilities together with fascinating electrical and magnetic or superconductive properties.™’ “ However, synthesis of pure borides with precise stoichiometries is often not easy because high temperatures and nonvolatile products are associated with the preparation methods.™
Therefore, complexes with direct bonding between the lanthanide and boron ligand are good candidates as precursors to lanthanide borides. Due to the limited radial extension of the 4f valence orbitals, the lanthanides are very electropositive and have little ligand stabilization energy. The lanthanides are thus considered as hard Lewis acids and prefer to coordinate to hard Lewis bases containing fluorine, oxygen and nitrogen atom donors.^ Therefore, direct covalent bonding between the lanthanides and boron is not expected and most likely hydrogen-bridged lanthanide-boron complexes are expected. Divalent lanthanide ions are softer than trivalent lanthanide ions due to the lower charge/size ratio and are believed to have a better chance of bonding to boron hydrides, which are not hard bases. Neutral solvent molecules fill the empty coordination sites of the lanthanide ions after bonding through the hydrogen bridges to the boron hydrides. If instead anionic ligands are employed, these might displace the boron hydrides fiom the lanthanide ion or it might form too stable complexes in which
15 the ligand cannot be removed during the thermal decomposition process. Hence, neutral solvent molecules such as acetonitrile, pyridine and THF are chosen because these solubilize lanthanide complexes and can be easily removed during the thermal decomposition process without contamination of the lanthanide borides.
Former studies have shown that the metathesis reaction between L^LnClj with
K[BHJ resulted in (CH3CN)4Yb[(p-H) 3BH]2 and (CH 3CN)2Eu[BH4]2, which led to YbB^ and EuBg.” YbB, and EuBg have pure +2 oxidation states among the lanthanide hexaborides and function as semiconductors.^ ” If L^Ln[B 3Hg] 2, (Ln = Yb, Eu; L =
CHjCN, C;H;N, THF) can be synthesized, these can be ideal candidates as precursors to lanthanide borides such as YbB« and EuBg since these complexes have the same stoichiometries as those in lanthanide borides.
16 CHAPTER 2
RESULTS AND DISCUSSION
1. (CHjCN)xYb[B3H8]2.1
The metathesis reaction between (NH 3)xYbCl2 and K[B 3Hg] in a 1 to 2 molar ratio in liquid NH3 yielded (NH 3)xYb[B3H8]2 (eqn. 1).
(NH3)xYbCl2 + 2 KP3H8] ------^ ----- ► (NH3)xYb[B3Ha]2 + 2 KOI (1)
Displacement of liquid NH 3 with the solvent CH 3CN and removal of KCl by filtration gave an orange filtrate. Slow removal of CH 3CN under dynamic vacuum from the
filtrate resulted in the viscous oil. Within 12 to 14 hours, orange crystals of
(CH3CN)4Yb[B3H8]2 were formed. The preliminary X-ray data collection of an orange crystal was performed by Dr. Jianping Liu. The structure is interesting since the two
[BgHg]' anions have different bonding modes (fig. 12). One [BsHg]' is bonded to the
Yb^^ ion through an unsupported B-H-Yb bridge and the other [BgHg]' is bonded through
a double B-H-Yb bridge. This is the first example in which [BgHg]* is bonded through
one boron. The coordination geometry of the Yb^^ ion is a distorted pentagonal
bipyramid. Two CH 3CN ligands are in the axial positions and the [BgHg]' anions are
17 C12
822 B21
C42 823 Ybl 813 N21 C21 812 C22 N31
C31
C32
Figure 12. The preliminary molecular structure of (CH3CN)4Yb[B3Hg] 2, 1.
18 Figure 13. 128 MHz “ B NMR spectra of(CH 3CN)4Yb[B3Hg] 2, 1, in CD3CN.
19 7 6 5 34 2 1 0 1 ppm
Figure 14. 400 MHz NMR spectra of (CH 3CN)4Yb[B3H8 ]2, 1, in CD 3CN.
20 approximately cis to each other in the equatorial plane. The removal of the solvent
CH 3C N resulted in an orange solid. The color of this solid is the same as that observed for the Yb(II) complexes of [BioHtof, [BioHu]^* and [BR,]* in CH 3C N .” ’ ^
The 128 MHz ‘‘B NMR spectrum of the orange solid in CD 3C N shows a broad singlet at
-27.7 ppm, which is 1.8 ppm downfield from the peak of the starting material, K[B 3Hg] at
-29.5 ppm (fig. 13). The 400 MHz ^H NMR spectrum contains a broad singlet at 0.61 ppm, which is 0.46 ppm downfield from the peak of K[B 3Hg] at 0.15 ppm (fig. 14).
These shifts suggest that [B 3Hg]' is coordinated to the Yb^^ ion and that the complex does not exist as a solvent-separated ion pair in solution. The "B{^H} and *H{^‘B} NMR spectra showed sharpening indicating the interaction between boron and hydrogen nuclei.
The ^‘B-'H coupling is broad and not resolved possibly due to the quadrupolar effect of the Yb^^ ion. The 400 MHz 'H NMR spectrum of the orange solid in d-THF displays a resonance for the coordinated CH 3C N ligands at 1.98 ppm. The presence of one ‘ ‘B resonance and one resonance for [B 3Hg]‘ may indicate fluxional behavior of 1 in solution. An elemental analysis of the orange solid, after washing with hexanes and vacuum-drying, was (CH3CN)o.6Yb[B3Hg] 2. This orange solid was further vacuum-dried giving a yellow solid with the formula, (CH 3CN)ojYb[B3Hg] 2. These analyses show that the coordinated solvent molecules can be removed although not completely under dynamic vacuum. Therefore, this complex can be a good precursor to lanthanide borides.
21 2. [Yb(CH3CN)8][BuHi2],2
The tiny red crystal, [Yb(CH 3CN)8 ][Bi2Hi2], 2 was obtained from the saturated acetonitrile filtrate of (CH3CN)4Yb[B3H8 ]2, 1, at -30 “C in the drybox refiigerator. The crystal structure was solved by Dr. Edward A. Meyers and Dr. Shengming Liu. Crystal data for 2 are listed in Table 1. Atomic coordinates for 2 are given in Table 2. Bond lengths and angles for 2 are reported in Table 3. The molecular structure of 2 is shown in figure IS. 2 crystallized in the monoclinic space group, Cc. It exists as the discrete
[Yb(CH3CN)8 ]^^ cation and the [B i 2Hi2]^' anion without any hydrogen bridges. The molecular structure of the [Bi2Hi2]^' anion is identical to that observed in other systems.^^’ The Yb(II) ion is ligated to eight CH 3CN molecules and has a square antiprismatic geometry. The average Yb-N distance is 2.571(7) Â and is comparable to those distances observed in [Yb(DIMEXCH 3CN)s][Bi2Hi2] (2.55(3) A), (CH3CN)6Yb[(p-
H)2B,oHi2] (2.54(9) A) and (CH 3CN)4Yb[(p-H) 3BH]2 (2.525(4) A).^’’ The average Yb-N-C bond angle of 164.4(6)° in 2 deviates significantly from linearity. Other acetonitrile complexes ofYb^^ show similar deviations, with average Yb-N-C angles of
162(4)°, 171(5)° and 171(6)° for [Yb(DlME)(CH 3CN)5][Bi2Hi2], (CHsChOeYbKp-
H)2BioHi2] and (CH 3CN)4Yb[(p-H) 3BH]2, respectively. An ' *B NMR spectrum of the mother liquor still showed a broad singlet around at -24.2 ppm. After 4 months, another spectrum was taken and a nonet was observed at -25.3 ppm. Thus, the majority of the mother liquor still existed as (CH 3CN)4Yb[B3H8 ]2, 1.
22 C fi
eu,
Ybl
Figure 15. Molecular structure of [Yb(CH3CN)g][Bi 2Hi2], 2.
23 empirical formula CigHagBizNgYb formula weight, amu 643.29
space group Cc
a , A 14.2260(10) b , A 13.1350(10) c, A 16.4780(10) P , d e g 90.000(30)
vol, A^ 3079.1(4)
Z 4
p (calcd), mg m'^ 1.388
crystal size, mm 0.23 X 0.15 X 0.12
T. “C -123 radiation (X,A) MoKa (0.71073) p, mm'*- 3.058
scctn mode CÛ at S5/-55
26 lim its , deg 4.90 - 50.06
+h -16, 16 ±k -15, 15 ±1 -19, 19 no. o f rfln s measd 35575
no. o f unique rfln s 5437
no. o f variables 335
[I> 2 o {I)] 0.0217
wj%/ (all data) 0.0424
GooF 1.036
* = SI I F o l-lF c l l/S IF o l " wFj = (S[w(Fo*-Fc*)*]/S[w(Fo*)*] }*'*
Table I. CrystaIlographicdatafor[Yb(CH 3CN)8 ][Bi2Hi2],2 .
24 Atom X y z U(eq)*
Yb(l) 9069(1) 517(1) 3234(1) 21(1) N(l) 7972(3) -475(2) 2246(2) 37(1) C(1A) 7612(3) -913(3) 1738(3) 30(1) C(1B) 7164(4) -1466(4) 1087(3) 51(1) N(2) 10871(3) 597(3) 3236(2) 37(1) C(2A) 11565(3) 1034(3) 3237(2) 27(1) C{2B) 12421(3) 1613(3) 3235(2) 23(1) N(3) 9651(2) 2378(3) 3233(2) 30(1) C(3A) 10050(3) 3128(3) 3234(2) 22(1) C(3B) 10589(3) 4076(3) 3247(2) 26(1) N(4) 7652(3) 1670(3) 3232(3) 55(1) C(4A) 7442(3) 2473(4) 3236(3) 35(1) C(4B) 7167(3) 3563(3) 3240(2) 30(1) N(5) 9598(2) -1345(2) 3235(2) 32(1) C(5A) 9781(2) -2182(3) 3233(2) 25(1) C(5B) 10016(3) -3263(3) 3231(2) 25(1) N(6) 7976(2) -473(2) 4220(2) 36(1) C(6A) 7614(3) -915(3) 4728(3) 31(1) C(6B) 7158(4) -1472(4) 5383(3) 53(1) N(7) 9557(2) 912(3) 4700(2) 34(1) C(7A) 9901(3) 1171(3) 5295(2) 25(1) C(7B) 10347(3) 1492(3) 6045(2) 30(1) N(8) 9559(2) 913(3) 1762(2) 32(1) C(8A) 9903(3) 1171(3) 1174(2) 25(1) C(8B) 10344(3) 1495(3) 426(2) 32(1) BCD 3153(4) -962(4) 5304(3) 25(1) B(2) 4402(4) -961(4) 5313(3) 22(1) B{3) 3776(4) -58(4) 4704(3) 21(1) B(4) 2765(4) 325(3) 5259(3) 21(1) B(5) 2768(4) -331(3) 6204(3) 23(1) B(6) 3778(4) -1119(3) 6224(3) 20(1) B(7) 4781(4) 333 (3) 5256(3) 22(1) B(8) 3783(4) 1118(4) 5243(3) 21(1) B(9) 3148(4) 960(4) 6156(3) 24(1) B(10) 3776(4) 49(4) 6763(3) 22(1) B(ll) 4781(4) -330(3) 6215(3) 22(1) B(12) 4393(4) 959(4) 6156(3) 21(1)
* U(eq) is defined as one third of the trace of the orthogonalized üij tensor.
Table 2. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ x 10^) for [Yb(CH3CN)8 ][Bi2Hi2], 2.
25 Bond Lengths Y b(l)-N(4) 2.522 (4) C(8B)-H(8B1) 0.9600 Y b(l)-N(5) 2.559(3) C(8B)-H(8B2) 0.9600 Yb(l)-N(2) 2.565(4) C(8B)-H(8B3) 0.9600 Yb(l)-N(7) 2.566(4) B (l)-B (6) 1.770(7) Y b(l)-N(8) 2.576(3) B (l)-B (2) 1.778(8) Y b(l)-N(3) 2.580(3) B (l)-B (4) 1.780(7) Yb(l) -N(6) 2.599(4) B (l)-B (3) 1.782(6) Y b (l)-N (l) 2.604(4) B (l)-B (5) 1.784(7) N(1)-C(1A) 1.137(5) B (l)-H (l) 1.1000 C(1A) -C(IB) 1.444(6) B(2)-B(6) 1.756(7) C(lB)-HdBl) 0.9600 B (2 )-B (ll) 1.784(7) C(1B) -H(1B2) 0.9600 B(2)-B(7) 1.784(7) C(1B) -H(1B3) 0.9600 B(2)-B(3) 1.790(7) N(2)-C(2A) 1.142(5) B(2)-H(2) 1.1000 C(2A) -C(2B) 1.436(6) B(3)-B(7) 1.771(7) C(2B)-H(2B1) 0.9600 B(3)-B(4) 1.777(7) C(2B)-H(2B2) 0.9600 B(3)-B(8) 1.782(7) C(2B)-H(2B3) 0.9600 B(3)-H(3) 1.1000 N(3)-C(3A) 1.137(4) B(4)-B(5) 1.779(6) C(3A) -C(3B) 1.463(6) B(4)-B(9) 1.783(6) C(3B) -H(3B1) 0.9600 B(4)-B(8) 1.784(7) C(3B)-H(3B2) 0.9600 B(4)-H(4) 1.1000 C(3B)-H(3B3) 0.9600 B(5)-B(6) 1.771(7) N(4)-C(4A) 1.095(5) B(5)-B(10) 1.776(7) C(4A) -C(4B) 1.485(6) B(5)-B(9) 1.781(7) C(4B)-H(4B1) 0.9600 B(5)-H(5) 1.1000 C(4B)-H(4B2) 0.9600 B (6 )-B (ll) 1.763(7) C(4B)-H(4B3) 0.9600 B(6)-B(10) 1.772(7) N(5)-C(5A) 1.130(4) B(6)-H(6) 1.1000 C(5A)-C(5B) 1.459(5) B(7)-B(8) 1.755(7) C(5B)-H(5B1) 0.9600 B(7)-B(12) 1.783(6) C(5B)-H(5B2) 0.9600 B (7 )-B (ll) 1.804(6) C(5B)-H(5B3) 0.9600 B(7)-H(7) 1.1000 N(6)-C(6A) 1.141(5) B(8)-B(12) 1.748(7) C(6A)-C(6B) 1.456(6) B(8)-B(9) 1.767(6) C(6B)-H(6B1) 0.9600 B(8)-H(8) 1.1000 C(6B)-H(6B2) 0.9600 B(9)-B(12) 1.771(7) C(6B)-H(6B3) 0.9600 B(9)-B(10) 1.797(7) N(7)-C(7A) 1.148(5) B(9)-H(9) 1.1000 C(7A)-C(7B) 1.452(6) B(10)-B(ll) 1.763(7) C(7B)-H(7B1) 0.9600 B(10)-B(12) 1.789(7) C(7B)-H(7B2) 0.9600 BdO)-H(lO) 1.1000 C(7B)-H(7B3) 0.9600 B(ll)-B(12) 1.784(7) N(8)-C(8A) 1.137(5) B d l ) - H ( l l ) 1.1000 C(8A) -C(8B) 1.448(6) B(12)-H(12) 1.1000
Angles N(4)-Yb(l)-N(5) 144.00(12) N(5)-Yb(l)-II(2) 75.28(11) N(4)-Yb(l)-N(2) 140.73(12) N(4)-Yb(l)-N(7) 95.47(12)
(to be continued)
Table 3. Bond lengths (A) and angles C) for [Yb(CH3CN)8 ][Bi2Hi2], 2.
26 Table 3. (continued)
N (5)-Y b (l -N(7) 96.49 11) C(4A)-C(4B)-H(4B3) 109.5 N (2)-Y b{l -N(7) 73.75 11) H(4B1)-C(4B)-H(4B3) 109.5 N (4)-Y b (l -N(8) 95.41 13) H(4B2)-C(4B)-H(4B3) 109.5 N (5)-Y b (l -N(8) 96.56 11) C(5A)-N(5)-Yb(l) 176.3(3) N (2)-Y b (l -N(8) 73.92 11) N(5)-C(5A)-C(5B) 179.9(5) N (7)-Y b (l -N(8) 140.56 10) C(5A)-C(5B)-H(5B1) 109.5 N{4) -Yb(l -N(3) 71.78 12) C(5A)-C(5B)-H(5B2) 109.5 N (5)-Y b (l -N(3) 144.22 11) H(5B1)-C(5B)-H(5B2) 109.5 N (2)-Y b{l -N(3) 68.95 10) C(5A)-C(5B)-H(5B3) 109.5 N (7)-Y b (l -N(3) 73.89 10) H(5B1)-C(5B)-H(5B3) 109.5 N (8)-Y b (l -N(3) 73.83 10) H(5B2)-C(5B)-H(5B3) 109.5 N (4)-Y b (l -N(6) 79.78 12) C(6A)-N(6)-Yb(l) 169.5(3) N (5)-Y b (l -N(6) 72.35 10) N(6)-C(6A)-C(6B) 179.4(5) N (2)-Y b (l -N(6) 128.13 11) C (6A)-C(6B)-H(6B1) 109.5 N (7)-Y b (l -N(6) 70.97 11) C(6A)-C(6B)-H(6B2) 109.5 N (8)-Y b (l -N(6) 148.40 11) H(6B1)-C(6B)-H(6B2) 109.5 N (3)-Y b (l -N(6) 131.79 10) C(6A)-C(6B)-H(6B3) 109.5 N (4)-Y b (l -N (l) 79.68 12) H(6B1)-C(6B)-H(6B3) 109.5 N (5)-Y b (l -N (l) 72.43 10) H(6B2)-C(6B)-H(6B3) 109.5 N (2)-Y b (l -N (l) 128.35 11) C(7A)-N(7)-Yb(l) 168.4(3) M (7)-Yb(l -N (l) 148.34 11) N(7)-C(7A)-C(7B) 179.3(4) N (8)-Y b (l -N (l) 71.04 10) C(7A)-C(7B)-H(7B1) 109.5 N (3)-Y b (l -N (l) 131.75 10) C(7A)-C(7B)-H(7B2) 109.5 N (6)-Y b (l -N (l) 77.38 11) H(7B1)-C(7B)-H(7B2) 109.5 C(1A) -N (l -Yb(l) 169.3C )) C(7A)-C(7B)-H(7B3) 109.5 N(l)-C{1A -C(IB) 179.4 (!5) H(7B1)-C(7B)-H(7B3) 109.5 C(1A)-C(1B)-H(1B1) 109.5 H(7B2)-C(7B)-H(7B3) 109.5 C(1A)-C(IB)-H(1B2) 109.5 C(8A)-N(8)-Yb(l) 168.1(3) H(1B1)-C(1B)-H(1B2) 109.5 N(8)-C(8A)-C(8B) 179.6(5) C(1A)-C(1B)-H{1B3) 109.5 C(8A)-C(8B)-H(8B1) 109.5 H(1B1)-C(1B)-H(1B3) 109.5 C(8A)-C(8B)-H(8B2) 109.5 H(1B2)-C(1B)-H(1B3) 109.5 H(8B1)-C(8B)-H(8B2) 109.5 C(2A)-N(2)-Yb{l) 152.2(3) C(8A)-C(8B)-H(8B3) 109.5 N(2)-C(2A)-C(2B) 178.2(4) H(8B1)-C 8B) -H(8B3) 109.5 C(2A)-C(2B)-H(2B1) 109.5 H(8B2)-C 8B)-H(8B3) 109.5 C(2A)-C(2B)-H(2B2) 109.5 B (6)-B (l -B(2) 59.4(3) H(2B1)-C(2B)-H(2B2) 109.5 B (6)-B (l -B(4) 107.6(3) C(2A)-C(2B)-H(2B3) 109.5 B(2)-B(l -B(4) 108.0(4) H(2B1)-C(2B)-H(2B3) 109.5 B (6)-B (l -B(3) 107.6(3) H(2B2)-C(2B)-H(2B3) 109.5 B(2)-B(l -B(3) 60.4(3) C(3A)-N(3)-Yb(l) 168.8(3) B (4)-B (l -B(3) 59.9(3) N(3)-C(3A)-C(3B) 178.2(4) B (6)-B (l -B(5) 59.8(3) C(3A)-C(3B)-H(3B1) 109.5 B (2)-B (l -B(5) 107.4(3) C(3A)-C(3B)-H(3B2) 109.5 B (4 )-B (l -B(5) 59.9(3) H(3B1)-C(3B)-H(3B2) 109.5 B (3 )-B (l -B(5) 107.7(3) C(3A)-C(3B)-H(3B3) 109.5 B (6 )-B (l -H (l) 122.2 H(3B1)-C(3B)-H(3B3) 109.5 B (2 )-B (l -H (l) 121.9 H(3B2)-C(3B)-H(3B3) 109.5 B(4)-B(l -H(l) 121.8 C(4A)-N(4)-Yb(l) 142.8(4) B (3 )-B (l -H (l) 121.7 M(4)-C(4A)-C(4B) 179.4(5) B (5 )-B (l -H (l) 122.0 C(4A)-C(4B)-H(4B1) 109.5 B(6)-B(2 -B(l) 60.1(3) C(4A)-C(4B)-H(4B2) 109.5 B(6)-B(2 -B (ll) 59.7(3) H(4B1)-C(4B)-H(4B2) 109.5 B(l)-B(2 -B(ll) 108.0(3) 27 Table 3. (continued)
B(6)-B(2)-B(7) 108.1(3) B(10)-B(5)-H(5) 121.2 B{l)-B(2)-B(7) 107.6(4) B(4)-B(5)-H(5) 121.7 B(ll)-B(2)-B{7) 60.7(3) B(9)-B(5)-H(5) 121.4 B(6)-B{2)-B(3) 107.8(4) B (l) -B(5) -H(5) 121.7 B(l)-B{2)-B(3) 59.9(3) B(2)-B(6)-B(ll) 60.9(3) B(ll)-B(2)-B(3) 108.1(3) B(2)-B(6)-B(l) 60.5(3) B(7)-B(2)-B{3) 59.4(3) B(ll)-B(6)-B(l) 109.3(3) B(6)-B(2)-H(2) 121.8 B(2)-B(6)-B(5) 108.9(3) B(l) -B(2) -H(2) 121.8 B(ll) -B(6)-B(5) 108.2(3) B(ll)-B(2)-H(2) 121.5 B(l) -B(6)-B(5) 60.5(3) B(7)-B(2)-H(2) 121.7 B(2)-B(6)-B(10) 109.1(3) B(3)-B(2)-H(2) 122.0 B(ll)-B(6)-B(10) 59.8(3) B(7)-B(3)-B(4) 107.9(3) B(l)-B(6)-B(10) 109.1(3) B(7)-B(3)-B(l) 108.0(3) B(5)-B(6)-B(IO) 60.1(3) B(4)-B{3)-B(l) 60.0(3) B(2)-B(6)-H(6) 120.8 B(7)-B{3)-B(8) 59.2(3) B(ll)-B(6)-H(6) 121.3 B(4)-B{3)-B(8) 60.2(3) B(l)-B(6)-H(6) 120.8 B(l)-B(3)-B(8) 107.7(3) B(5)-B(6)-H(6) 121.5 B(7)-B{3)-B(2) 60.1(3) B(10)-B(6)-H(6) 121.4 B(4)-B{3)-B(2) 107.5(3) B(8)-B(7)-B(3) 60.7(3) B(l)-B(3)-B(2) 59.7(3) B(8)-B(7)-B(12) 59.2(3) B(8)-B(3)-B(2) 106.9(3) B(3)-B(7)-B(12) 108.1(4) B(7) -B(3) -H(3) 121.8 B(8)-B(7)-B(2) 108.4(4) B(4)-B(3)-H(3) 121.7 B(3) -B(7)-B(2) 60.5(3) B(l)-B(3)-H(3) 121.7 B(12)-B(7)-B(2) 107.6(3) B(8)-B(3)-H(3) 122.3 B(8)-B(7)-B(ll) 107.1(3) B(2)-B(3)-H(3) 122.2 B(3)-B(7)-B(ll) 108.1(3) B(3)-B(4)-B(5) 108.1(3) B(12)-B(7)-B(ll) 59.6(3) B(3)-B(4)-B(l) 60.1(3) B(2) -B (7 )-B (ll) 59.6(2) B(5) -B(4) -B (l) 60.2(2) B(8) -B(7)-H(7) 121.9 B{3)-B(4)-B(9) 108.2(4) B(3) -B(7) -H(7) 121.1 B(5)-B(4)-B(9) 60.0(3) B(12)-B(7)-H(7) 122.2 B(l)-B(4)-B(9) 108.4(3) B(2)-B(7)-H(7) 121.6 B(3)-B{4)-B(8) 60.1(3) B(ll)-B(7)-H(7) 122.3 B(5)-B(4)-B(8) 107.0(3) B(12)-B(8)-B(7) 61.2(3) B(l)-B(4)-B{8) 107.7(4) B(12)-B(8)-B(9) 60.5(3) B(9)-B{4)-B(8) 59.4(3) B(7)-B(8)-B(9) 109.5(3) B(3)-B{4)-H(4) 121.4 B(12)-B(8)-B(3) 109.2(3) B(5)-B(4)-H{4) 121.9 B(7)-B(8)-B(3) 60.1(3) B(l)-B(4)-H(4) 121.5 B(9)-B(8)-B(3) 108.7(3) B(9)-B(4)-H(4) 121.7 B(12)-B(8)-B(4) 108.7(3) B(8)-B(4)-H(4) 122.4 B(7)-B(8)-B(4) 108.3(3) B(6)-B(5)-B(10) 59.9(3) B(9)-B(8)-B(4) 60.3(3) B(6) -B(5) -B(4) 107.5(3) B(3)-B(8)-B(4) 59.8(3) B(10)-B(5)-B(4) 108.7(3) B(12)-B(8)-H(8) 120.8 B(6)-B(5)-B(9) 108.1(4) B(7)-B(8)-H(8) 121.0 B(10)-B(5)-B(9) 60.7(3) B(9)-B(8)-H(8) 121.0 B(4) -B(5) -B(9) 60.1(2) B(3)-B(8)-H(8) 121.5 B(6)-B(5)-B(l) 59.7(3) B(4)-B(8)-H(8) 121.8 B(10)-B(5)-B(l) 108.3(4) B(8)-B(9)-B(12) 59.2(3) B(4)-B(5)-B(l) 59.9(3) B(8)-B(9)-B(5) 107.7(3) B(9)-B(5)-B(l) 108.2(3) B(12)-B(9)-B(5) 107.7(4) B(6)-B(5)-H(5) 122.1 B(8)-B(9)-B(4) 60.3(3) 28 Table 3. (continued)
B(12)-B(9)-B(4) 107.8(3) B(6)-B(ll)-B(12) 107.9(4) B(5)-B(9)-B(4) 59.9(3) B(10)-B(ll)-B(2) 108.2(4) B(8)-B(9)-B(10) 107.3(3) B(6)-B(ll)-B(2) 59.4(3) B(12)-B(9)-B{10) 60.2(3) B(12)-B(ll)-B(2) 107.5(3) B(5)-B(9)-B(IO) 59.5(3) B(10)-B(ll)-B(7) 108.2(3) B(4)-B{9)-B(IO) 107.6(3) B(6)-B(ll)-B(7) 106.9(3) B{8)-B(9)-H(9) 122.1 B(12)-B(ll)-B(7) 59.6(2) B(I2)-B(9)-H(9) 122.0 B(2)-B(ll)-B(7) 59.6(3) B{5) -B(9)-H{9) 122.0 B(10)-B(ll)-H(ll) 121.0 B(4)-B(9)-H(9) 121.7 B(6)-B(ll)-H(ll) 122.2 B(10)-B(9)-H(9) 122.1 B(12)-B(ll)-H(ll) 121.7 B(ll)-B(IO)-B(6) 59.8(3) B(2)-B(ll)-H(ll) 122.1 B(ll)-B(10)-B(5) 108.0(3) B(7)-B(ll)-H(ll) 122.2 B(6)-B(10)-B(5) 59.9(3) B(8)-B(12)-B(9) 60.3 (3) B(ll)-B(10)-B(12) 60.3(3) B(8)-B(12)-B(7) 59.6(3) B(6)-B(IO)-B(12) 107.3(3) B(9)-B(12)-B(7) 108.1(3) B(5)-B(10)-B(12) 107.1(3) B(8)-B(12)-B(ll) 108.3(3) B(ll)-B(10)-B(9) 107.8(3) B(9)-B(12)-B(ll) 108.0(3) B(6)-B(IO)-B(9) 107.4(3) B(7)-B(12)-B(ll) 60.8(3) B(5)-B(IO)-B(9) 59.8(3) B(8)-B(12)-B(IO) 108.5(4) B(12)-B(10)-B(9) 59.2(3) B(9)-B(12)-B(IO) 60.6(3) B(ll)-B(10)-H(10) 121.4 B(7)-B(12)-B(IO) 108.0(3) B(6)-B(IO)-H(IO) 122.1 B(ll)-B(12)-B(IO) 59.1(3) B(5)-B(IO)-H(IO) 121.9 B(8)-B(12)-H(12) 121.6 B(12)-B(10)-H{10) 122.3 B(9)-B(12)-H(12) 121.4 B(9)-B(10)-H(10) 122.2 B(7)-B(12)-H(12) 121.7 B(10)-B{ll)-B{6) 60.3(3) B(ll)-B(12)-H(12) 121.7 B{10)-B(ll)-B{12) 60.6(3) B(10)-B(12)-H(12) 121.7
29 3. (CH3CN)6Yb[(H.H)2BiiHu],3
A few orange crystals of (CH 3CN)6Yb[(p-H)zB uHt i], 3 were grown from a concentrated acetonitrile/hexane layered solution of (CH 3CN)4Yb[B3Hg] 2, 1 at -30 °C in the drybox refrigerator. The crystal structure was solved by Dr. Shengming Liu.
Crystallographic data for 3 are given in Table 4. Atomic coordinates for 3 are listed in
Table 5. Bond lengths and angles for 3 are reported in Table 6. The molecular structure of 3 is shown in figure 16. 3 cystallized in the monoclinic space group, P2|/c. The
Yb(II) ion is bonded to six CH 3CN ligands and two boron atoms of [BuHi 3]^' through two three-center two-electron B-H-Yb bridges. The coordination geometry of the Yb^^ ion is approximately square antiprismatic. The BuHn unit coordinates to ytterbium through two B-H-Yb bridges from adjacent BH(7) and BH( 8 ) positions on the boron cage with a H(7)-Yb-H(8) angle of 72.8(9)®. As a note, a B iqHh unit was shown to bond to ytterbium through two B-H-Yb bridges from adjacent boron atom of the cage with a corresponding H-Yb-H angle of 68(4)®.^^ All of the hydrogen atoms on the B11 cage were located and isotropically refined from the X-ray data. The distances between
ytterbium and the bridging hydrogens are 2.31(3) A for Yb-H(7) and 2.69(3) A for Yb-
H(8 ). The average Yb-H distance, 2.50(3) A, is not significantly different from
(CH3CN)6Yb[(n-H)2B,oHi2]'2CH3CN (2.3(1) A) and (CH 3CN)4Yb[(p-H) 3BH]2 (2.4(1)
A).^7>2*. 29 The average Yb-N distance is 2.554(4) A and is comparable to the other
acetonitrile complexes of Yb^^ including 2?^' As observed with 2 and other
CH3CN complexes of Yb^^, the average Yb-N-C bond angle of 162.1(2)® in 3 deviates
significantly from linearity.” ’ ” The ' ‘B NMR spectrum of the mother liquor
showed a nonet at 5 -28.1 (Jbh = 33 Hz) which suggests that the solution is predominately
30 CIS C11A Ybl H12
iHK) BIO
HI
Figure 16. Molecular structure of (CH3CN)6Yb[(n-H)2BtiHn], 3.
31 • a • I l Mt M# 40
Figure 17. 160 MHz ^ ‘B NMR spectra of crystals of (CH 3CN)gYb[(p-H) 2BnHi i], 3 in
32 empirical formula Ci«H37BixNaYb formula weight, amu 633.49
space group P2i/c
a, k 9.5097(10) b, k 14.1574(10)
c, A 22.8192(10)
3, deg 97.321(10)
vol, A' 3047.2(4)
Z 4
p (calcd), mg m"' 1.381
crystal size, mm 0.27 X 0.25 X 0.19 r, °c -123 radiation (\,A) MoKa (0.71073) fi, mm'^ 3.090
scan mode w at S5/-55
20 limits, deg 4.60 - 50.06 ±h -11 , 11 ±k -16, 15 ±1 -27, 26 no. of rfln s measd 45877
no. of unique rfln s 5369
no. of variables 473
[I> 2 o (I)l 0.0227
wa/ (all data) 0.0563
GooF 1.062
* R i = SI IFol-|Fcl l/SIFol wRj = {S[w(Fo'-F/)*]/S[w(Fo*)*]
Table 4. Crystallographic data for (CH 3CN)6Yb[(ji-H)2BiiHn], 3.
33 Atom X y z U(eq)‘
Yb(l) 1897(1) 6494(1) 3334(1) 18(1) B(l) 3067(3) 6812(2) 1049(1) 22 (1) B(2) 1634(3) 6245(2) 1336(1) 21(1) B(3) 2355(3) 7285(2) 1666(1) 20(1) B(4) 4240(3) 7266(2) 1662(1) 21(1) B{5) 4638(3) 6196(2) 1303(1) 20(1) B(6) 3040(3) 5550(2) 1105(1) 22(1) B(7) 1887(3) 6337(2) 2110(1) 19(1) B(8) 3502(3) 6950(2) 2324(1) 21(1) B(9) 5049(3) 6297(2) 2073(1) 21(1) B(10) 4289(3) 5191(2) 1718(1) 23(1) B (ll) 2312(3) 5253(2) 1771(1) 24(1) N(ll) -791(3) 6726(2) 3306(1) 33(1) C(llA) -1822(3) 7089(2) 3374(1) 27(1) C(llB) -3130(3) 7560(3) 3470(2) 38(1) N(12) 1147(3) 4749(2) 3288(1) 34(1) C(12A) 1276(3) 3950(2) 3270(1) 30(1) C{12B) 1475(4) 2935(3) 3251(2) 43(1) N(13) 4143(3) 5517(2) 3510(1) 34(1) C{13A) 5183 (3) 5175(2) 3421(1) 30(1) C{13B) 6498(4) 4747(3) 3296(2) 40(1) N{14) 1283(3) 8233(2) 3119(1) 33(1) C{14A) 1365(3) 9026(2) 3092(1) 27(1) C{14B) 1504(5) 10042(3) 3065(2) 40(1) N(15) 3562(3) 7555(2) 4007(1) 34(1) C(15A) 4004(3) 8168(2) 4287(1) 26(1) C(15B) 4558(4) 8973(3) 4639(2) 36(1) N(16) 1341(3) 6251(2) 4382(1) 37(1) C(16A) 978(3) 6203(2) 4839(1) 28(1) C(16B) 523(4) 6148(3) 5416(1) 34(1) N(l) -1920(4) 8084(3) 5050(2) 69(1) C(l) 160(4) 8851(3) 4615(2) 46(1) C(2) -1002(4) 8417(2) 4858(2) 42(1) N(2) 7093(4) 5657(3) 4645(2) 69(1) C(3) 5499(6) 6435(3) 5337(2) 54(1) C(4) 6393(4) 5991(2) 4949(2) 41(1)
• ü(eq) is defined as one third of the trace of the orthogonalized Uij tensor.
Table S. Atomic coordinates ( x 10"*) and equivalent isotropic displacement parameters (A^ x 10^) for (CH 3CN)6Yb[(p-H) 2BiiHu], 3.
34 Bond Lengths Yb(l) -N(13) 2.533(2) B lO )-B (ll) 1.901(5) Yb{l)-N(16) 2.538(3) B lO)-H(lO) 1.13(3) Yb(l)-N(15) 2.550(2) B 10)-H(13) 1.33(3) Yb(l) -N(14) 2.564(3) B l l ) - H ( l l ) 1.13(3) Yb(l)-N{11) 2.570(3) B 11)-H(13) 1.27(3) Yb(l)-N(12) 2.570(3) N ll)- C ( llA ) 1.136(4) Yb{l) -B(7) 2.801(3) CllA) -C(llB) 1.452(4) Y b(l)-B(8) 2.991(3) C IIB)-H(llC) 0.85(4) Yb(l) -H(7) 2.31(3) c IIB)-H(llB) 0.99(5) Y b(l)-H(8) 2.69(3) c IIB)-H(llA) 0.90(5) B (l)-B (5) 1.762(4) N 12)-C(12A) 1.139(4) B (l)-B{3) 1.770(4) c 12A) -C(12B) 1.452(5) B (l)-B (2) 1.778(4) c 12B)-H(12C) 0.86(5) B (l)-B (6) 1.793(5) c 12B)-H(12B) 0.88(5) B (l)-B (4) 1.794(4) c 12B)-H(12A) 0.96(5) B (l)-H (l) 1.06(3) N 13)-C(13A) 1.143(3) B(2)-B(3) 1.753(4) C 13A)-C(13B) 1.450(4) B(2)-B(7) 1.757(4) C 13B)-H(13C) 0.89(5) B (2 )-B (ll) 1.792(4) C 13B)-H(13B) 1.03(4) B(2) -B(6) 1.793 (4) C 13B)-H(13A) 0.85(4) B(2)-H(2) 1.14(3) N 14)-C(14A) 1.127(4) B(3)-B(7) 1.772(4) C 14A)-C(14B) 1.446(5) B{3)-B(4) 1.794(4) C 14B)-H(14C) 0.96(4) B(3)-B{8) 1.804(4) C 14B)-H(14B) 0.67(5) B(3)-H(3) 1.09(3) C 14B)-H(14A) 0.76(4) B{4)-B(9) 1.779(4) N 15)-C(15A) 1.127(3) B(4)-B(5) 1.785(4) C 15A)-C(15B) 1.453(4) B(4)-B(8) 1.802(4) C 15B)-H(15C) 0.87(3) B(4)-H(4) 1.11(3) C 15B)-H(15B) 0.90(4) B(5)-B(9) 1.756(4) C 15B)-H(15A) 0.84(7) B(5)-B(10) 1.764(5) N 16)-C(16A) 1.140(4) B{5)-B(6) 1.782(4) C 16A)-C(16B) 1.439(4) B(5)-H(5) 1.05(3) C 16B)-H(16C) 0.81(4) B(6)-B(10) 1.789(4) C 16B)-H(16B) 0.93(4) B (6 )-B (ll) 1.797(4) C 16B)-H(16A) 0.97(4) B(6)-H(6) 1.13(3) N 1) -C(2) 1.128(5) B(7)-B(8) 1.777(4) C 1)-C(2) 1.436(6) B (7 )-B (ll) 1.788(4) C I)-H(IC) 0.90(4) B(7)-H(7) 1.14(3) C I)-H(IB) 0.93(4) B{8)-B{9) 1.889(4) C I)-H(IA) 0.83(5) B{8)-H(8) 1.11(3) N 2)-C(4) 1.125(4) B{8)-H(12) 1.30(3) C 3)-C(4) 1.446(6) B{9)-B(10) 1.865(4) C 3)-H(3C) 0.87(5) B{9)-H(9) 1.12(3) c 3)-H(3B) 0.90(5) B(9)-H(12) 1.25(3) c 3)-H(3A) 0.92(4)
(to be continued)
Table 6. Bond lengths (A) and angles (®) for (CH 3CN)«Yb[(^i-H)2B uHn], 3.
35 Table 6. (continued)
Angles N 13 -Y b(l -N{16) 92.82(8) B(3 -B(l -B(4) 60 .44(17) N 13 -Yb(l -N{15) 77.28(8) B(2 -B (l -B(4) 107 .7(2) N 16 -Yb(l -N{15) 72.55(8) B(6 -B (l -B(4) 108 .3(2) N 13 -Yb(l -N{14) 136.19(8) B(5 -B (l -H (l) 117 .8(14) N 16 -Yb(l -N(14) 103.94(8) B(3 -B(l -H(l) 124 .9(15) N 15 -Yb(l -N(14) 70.02(8) B(2 -B (l -H (l) 124 .4(15) N 13 -Yb(l -N(ll) 152.81(8) B(6 -B (l -H(l) 119.7(15) N 16 -Yb(l -NCll) 73.43(8) B(4 -B (l -H (l) 121 .1(15) N 15 -Yb(l -N(ll) 118.62(8) B(3 -B(2 -B(7) 60 .64(17) N 14 -Yb(l -N(ll) 70.80(8) B(3 -B(2 -B(l) 60 .17(18) N 13 -Yb(l -N(12) 72.87(8) B(7 -B(2 -B (l) 108 .9(2) N 16 -Yb{l -N{12) 79.52(8) B(3 -B(2 -B(ll) 109 .1(2) N 15 -Yb(l -N{12) 137.62(8) B(7 -B(2 -B (ll) 60 .52(17) N 14 -Yb{l -N(12) 149.36(9) B(1 -B(2 -B (ll) 108 .6(2) N 11 -Yb(l -N(12) 81.48(8) B(3 -B(2 -B(6) 108 .8(2) N 13 -Yb(l -B(7) 90.60(8) B(7 -B(2 -B(6) 108.9(2) N 16 -Yb(l -B(7) 162.65(9) B(1 -B(2 -B(6) 60 .27(17) N 15 -Yb(l -B(7) 124.77(8) B(1 )-B( t)-B(6) 60.15(17) N 14 -Yb(l -B(7) 85.03(9) B(3 -B(2 -H(2) 123 .5(15) N 11 -Yb(l -B(7) 96.22(9) B(7 -B(2 -H(2) 121.1(14) N 12 -Yb(l -B(7) 85.27(8) B(1 -B(2 -H(2) 122 .8(14) N 13 -Yb(l -B(8) 74.78(8) B(1 )-B (2)-H (2) 118 .9(15) N 16 -Yb(l -B(8) 160.57(8) B(6 -B(2 -H (2) 119 .8(14) N 15 -Yb(l -B(8) 89.90(8) B(2 -B(3-B(l) 60 .59(18) N 14 -Yb(l -B{8) 76.78(8) B(2 -B(3 -B(7) 59 .77(17) N 11 -Yb{l -B{8) 123.82(8) B(1 -B(3 -B(7) 108 .5(2) N 12 -Yb(l -B{8) 110.00(8) B(2 -B(3 -B(4) 108 .8(2) B 7) •Yb(l) -B(8) 35.53(8) B(1 -B(3 -B(4) 60 .43(17) N 13 -Yb(l -H(7) 111.1(7) B(7 -B(3 -B(4) 108 .3(2) N 16 -Yb(l -HC7) 143.4(7) B(2 -B(3 -B(8) 107 .4(2) N 15 -Yb(l -H(7) 138.1(6) B(1 -B(3 -B(8) 108 .1(2) N 14 -Yb(l -H(7) 78.1(6) B(7 -B(3 -B(8) 59 .57(17) N 11 -Yb(l -H(7) 72.9(7) B(4 -B(3 -B(8) 60 .10(17) N 12 -Yb(l -H(7) 81.6(6) B(2 -B(3 -H(3) 123 .2(13) B 7) ■Yb(l) -H(7) 23.3(7) B(1 -B(3 -H(3) 123 .0(13) B 8) -Yb(l) -H{7) 56.1(7) B(7 -B(3 -H(3) 120 .8(13) N 13 -Yb(l -H(8) 77.3(6) B(4 -B(3 -H(3) 120 .7(13) N 16 -Yb(l -H(8) 141.7(6) B(8 -B(3 -H(3) 120 .1(13) N 15 -Yb(l -H(8) 69.2(6) B(9 -B(4 -B(5) 59 .02(17) N 14 -Yb(l -H(8) 64.4(6) B(9 -B(4 -B (l) 108 .6(2) N 11 -Yb(l -H{8) 127.8(6) B(5 -B(4 -B (l) 59 .00(17) N 12 -Y b(l -H{8) 129.9(6) B(9 -B(4 -B(3) 112 .0(2) B 7)--Yb(l) -H{8) 55.5(6) B(5 -B(4 -B(3) 106 .6(2) B 8)--Yb(l) -H(8) 21.7(6) B(1 -B(4 -B(3) 59 .13(17) H 7)-■Yb{l) -H(8) 72.8(9) B(9 -B (4 -B(8) 63 .65(17) B 5)--B(l)-B(3) 108.6(2) B(5 -B(4 -B(8) 107 .6(2) B 5).-B(l)-B(2) 108.2(2) B(1 -B(4 -B(8) 107 .2(2) B 3)--B(l)-B(2) 59.23(17) B(3 -B(4 -B(8) 60 .22(16) B 5)--B(l)-B(6) 60.14(18) B(9 -B(4 -H (4) 120 .8(14) B 3)--B(l)-B(6) 108.0(2) B(5 -B(4 -H(4) 118 .9(14) B 2)--B(l)-B(6) 60.30(18) B(1 -B(4 -H (4) 117 .8(13) B 5)--B(l)-B(4) 60.25(17) B(3 -B(4 -H(4) 122 .4(14) 36 Table 6. (continued)
B(8)-B{4)-H(4) 126.8(14) B(4)-B(8)-Yb(l) 172.28(18) B(9)-B(5)-B(l) 111.1(2) B(3)-B(8)-Yb(l) 112.62(16) B(9)-B(5)-B(IO) 63.99(18) B(9)-B(8)-Yb(l) 128.52(17) B(l) -B(5) -B(IO) 111.5(2) B(7)-B(8)-H(8) 123.3(14) B(9)-B(5)-B(6) 111.7(2) B(4)-B(8)-H(8) 119.0(14) B(l)-B(5)-B(6) 60.78(17) B(3)-B(8)-H(8) 120.8(14) B(10)-B(5)-B(6) 60.61(18) B(9)-B(8)-H(8) 120.3(14) B(9)-B(5)-B{4) 60.33(17) Yb(l)-B(8)-H(8) 63.5(14) B(l) -B(5) -B{4) 60.75(18) B(7)-B(8)-H(12) 95.8(13) B(10)-B(5)-B(4) 111.9(2) B(4)-B(8)-H(12) 98.4(13) B(6)-B(5)-B(4) 109.2(2) B(3)-B(8)-H(12) 132.6(13) B(9)-B(5)-H(5) 114.7(14) B(9)-B(8)-H(12) 41.1(12) B(l) -B(5) -H(5) 124.9(14) Yb(l)-B(8)-H(12) 87.5(13) B(10)-B(5)-H(5) 115.0(15) H(8)-B(8)-H(12) 106.6(19) B{6)-B(5)-H(5) 122.8(14) B(5)-B(9)-B(4) 60.65(17) B(4)-B(5)-H(5) 121.9(15) B(5)-B(9)-B(IO) 58.23(17) B{5)-B(6)-B(IO) 59.22(17) B(4)-B(9)-B(IO) 107.5(2) B(5)-B(6)-B(l) 59.08(17) B(5)-B(9)-B(8) 105.1(2) B(10)-B(6)-B(l) 109.0(2) B(4)-B(9)-B(8) 58.75(16) B(5)-B(6)-B(2) 106.7(2) B(10)-B(9)-B(8) 105.6(2) B(10)-B(6)-B(2) 111.8(2) B(5)-B(9)-H(9) 120.6(14) B(l)-B(6)-B(2) 59.43(17) B(4)-B(9)-H(9) 116.7(13) B(5)-B(6)-B(ll) 108.3(2) B(10)-B(9)-H(9) 125.7(13) B(10)-B(6)-B(ll) 64.03(18) B(8)-B(9)-H(9) 123.4(14) B(l) -B(6) -B(ll) 107.7(2) B(5)-B(9)-H(12) 129.1(14) B(2)-B(6)-B(ll) 59.88(17) B(4)-B(9)-H(12) 101.8(14) B(5)-B{6)-H{6) 123.3(13) B(10)-B(9)-H(12) 88.9(14) B(10)-B(6)-H(6) 120.9(13) B(8)-B(9)-H(12) 43.4(14) B(l)-B{6)-H{6) 120.4(14) H(9) -B(9)-H(12) 110.1(19) B(2)-B(6)-H(6) 120.0(13) B(5)-B(10)-B(6) 60.17(18) B(ll)-B(6)-H(6) 121.8(13) B(5)-B(10)-B(9) 57.78(17) B(2) -B(7) -B(3) 59.58(17) B(6)-B(10)-B(9) 106.4(2) B(2)-B(7)-B(8) 108.4(2) B(5)-B(10)-B(ll) 104.5(2) B(3)-B(7)-B(8) 61.10(17) B(6)-B(10)-B(ll) 58.18(16) B(2)-B(7)-B(ll) 60.71(18) B(9)-B(10)-B(ll) 105.4(2) B(3) -B(7) -B (ll) 108.4(2) B(5)-B(10)-H(10) 123.7(14) B(8)-B(7)-B(ll) 107.6(2) B(6)-B(10)-H(10) 120.3(14) B(2)-B(7)-Yb(l) 172.36(19) B(9)-B(10)-H(10) 125.0(15) B(3)-B(7)-Yb(l) 122.75(17) B(ll)-B(10)-H(10) 122.6(15) B(8)-B(7)-Yb{l) 78.10(14) B(5)-B(10)-H(13) 125.5(13) B(ll)-B(7)-Yb{l) 121.84(17) B(6)-B(10)-H(13) 99.2(12) B(2)-B(7)-H{7) 118.8(14) B(9)-B(10)-H(13) 87.3(13) B(3)-B(7)-H{7) 117.3(12) B(ll)-B(10)-H(13) 41.8(12) B(8)-B(7)-H{7) 121.7(13) H(10)-B(10)-H(13) 110.4(19) B(ll) -B(7)-H{7) 124.0(12) B(7)-B(ll)-B(2) 58.77(17) Yb{l) -B(7)-H(7) 53.6(14) B(7)-B(ll)-B(6) 107.4(2) B(7)-B(8)-B{4) 107.8(2) B(2)-B(ll) -B(6) 59.97(17) B(7)-B(8)-B{3) 59.32(16) B(7)-B(ll) -B(IO) 110.3(2) B(4)-B{8)-B{3) 59.67(16) B(2)-B(ll) -B(IO) 106.9(2) B(7)-B(8)-B{9) 110.9(2) B(6)-B(ll)-B(10) 57.80(16) B(4)-B(8)-B{9) 57.60(16) B(7)-B(ll)-H(ll) 122.7(15) B(3)-B(8)-B(9) 106.7(2) B(2)-B(ll)-H(11) 122.0(16) B(7)-B(8)-Yb(l) 66.37(13) B(6)-B(ll)-H(ll) 120.8(16) 37 Table 6. (continued)
B 10)-B(11)-H(11) 120.5 16) H 14C)-C(14B) -H(14B) 109(5 B 7)-B(ll)-H(13) 91.1 13) C 14A) -C(14B)-H(14A) 112(4 B 2)-B(ll)-H(13) 130.8 13) H 14C)-C(14B)-H(14A) 131(4 B 6)-B(ll)-H(13) 101.3 13) H 14B)-C(14B)-H(14A) 77(5 B 10)-B(11)-H(13) 44.3 13) C ISA) -N (15)-Yb(l) 162.4 2) H 11)-B{11)-H(13) 107(2 N 15)-C(15A)-C(15B) 178.7 4) C IIA) -N(ll) -Yb(l) 158.2 2) C 15A)-C(15B)-H(15C) 105(2 N 11)-C(llA)-C(llB) 179.0 4) C 15A)-C(15B)-H(15B) 111(2 C IIA)-C(llB)-H(llC) 113(3 H 15C)-C(15B)-H(15B) 125(3 C IIA)-C(llB)-H{11B) 110(3 C ISA) -C(ISB)-H(15A) 117(5 H IIC)-C(llB)-H(llB) 112(4 H 1SC)-C(1SB)-H(15A) 94(4 C IIA) -C(llB)-H(llA) 114(3 H 1SB)-C(15B)-H(1SA) 105(5 H lie)-C(llB)-H(llA) 91(4 C 16A) -N (16)-Yb(l) 173.0 3) H 11B)-C(11B)-H(11A) 116(4 N 16)-C(16A)-C(16B) 179.7 4) C 12A) -N(12)-Yb(l) 157.7 3) C 16A)-C(16B)-H(16C) 110(3 N 12)-C(12A)-C(12B) 178.7 4) C 16A)-C(16B)-H(16B) 111(2 C 12A)-C(12B)-H(12C) 112(3 H 16C)-C(16B)-H(16B) 118(4 C 12A)-C(12B)-H(12B) 103(3 C 16A)-C(16B)-H(16A) 112(2 H 12C)-C(12B)-H(12B) 111(4 H 16C)-C(16B)-H(16A) 101(3 C 12A)-C(12B)-H(12A) 119(3 H 16B)-C(16B)-H(16A) 104(3 H 12C)-C(12B)-H(12A) 103(4 C 2)-C(l)-H(lC) 108(3 H 12B)-C(12B)-H(12A) 109(4 C 2)-C(l)-H(lB) 108(2 C 13A) -N(13)-Yb(l) 159.2 2) H 1C)-0(1)-H(IB) 112(4 N 13)-C(13A)-C(13B) 178.8 3) C 2)-C(l)-H(lA) 110(3 C 13A)-C(13B)-H(130) 108(3 H 1C)-C(1)-H(1A) 103(4 C 13A)-C(13B)-H{13B) 112(2 H 1B)-C(1)-H(1A) 114(4 H 13C)-C(13B)-H{13B) 119(3 N 1)-C(2)-C(l) 179.3 4) C 13A)-C(13B)-H(13A) 107(3 C 4)-C(3)-H(3C) 105(3 H 130)-C(13B)-H(13A) 107(4 C 4)-C(3)-H(3B) 109(3 H 13B)-C(13B)-H(13A) 104(4 H 30 -C(3)-H(3B) 119(4 C 14A)-N(14)-Yb(l) 162.1 2) C 4)-C(3)-H(3A) 115(3 N 14)-C(14A)-C(14B) 178.6 4) H 30 -C(3)-H(3A) 104(4 C 14A)-C(14B)-H(14C) 110(3 H 3B) -C(3) -H(3A) 105(4 C 14A)-C(14B)-H(14B) 113(5 N 2)-C(4)-C(3) 179.1 4)
38 (CH3CN)4Yb[B3H8 ]2, 1 The ‘ B NMR spectra of crystals of 3 ia consists of three doublets at -14.6 (Jbh = 143 Hz), -16.3 (Jbh =115 Hz), and -17.2 ppm (Jbh = 131
Hz), in a ratio of 1:5:5, corresponding to boron atoms 1,2-6 or 7-11 (fig. 17). The equivalence of the upper belt and lower belt boron nuclei indicate fluxional behavior of 3 in solution. This ' NMR spectrum shows an interesting contrast to that of K 2[B uHn] in KOH, which consists of two doublets at -20.3 and -31.5 ppm in an intensity ratio 10:1 and both B-H coupling constants are 125 Hz.^° The ' *B resonances of coordinated
[BiiHu]^' is shifted downfield relative to free [BuHu]^' suggesting that the [BuHi 3]^' anion is bonded to Yb^*.
4.(C5H5N)xYb[B3Hg]2.4
Displacement of NH 3 of (NH 3)%Yb[B3H 8 ]2 with C 5H 5N and subsequent filtration yielded a violet filtrate. The color of (C 5H;N)%Yb[B3Hg ]2 is the same as the Yb(II) complexes of[B.oHio]^ [BioHh]^' and [BH 4 ] ' in CsHsN.^^’ “ An ‘ *B NMR spectrum at 20 °C consists of a quartet a t-11.7 ppm (Jbh = 96 Hz) and a nonet at -28.7 ppm (Jbh = 31 Hz) (fig. 18,293 K). The quartet corresponds to C 5H 5NBH 3 and the nonet to (C5HsN)xYb[B3Hg] 2. The presence of a small amount of (CsH 5N)xYb[BH4]2 is evidenced as a quintet at -32.5 ppm (Jbh = 83 Hz). (C 5HsN)xYb[BH4]2 formed from
K[BH4], that was not effectively removed from the starting material, K[B 3Hg] (eqn. 2).^^
A 'H NMR spectrum at 20 °C consists of a quartet at 3.35 ppm (Jbh = 105 Hz) and a broad singlet at 1.79 ppm (br s) (fig. 19,293 K). The quartet is assigned to the terminal hydrogens of C 3H 5NBH 3 and the broad singlet to the hydrogens of (C 5H 5N )x Y b (B 3Hg] 2 .
The broadening of the H NMR resonance of [B gH g]' may be indicative of the
39 quadrupolar effect of the nucleus. The variable temperature ' B and 'H NMR spectra of (C 5H sN )* Y b [B 3H 8 ]2 were taken inC 5D 5N from 233 K to 353 K. The [BsHs]* anion is still fluxional even at 233 K. At low temperature, B-H coupling is not observed in ^ ‘B NMR spectra but increasing temperature resolves the coupling. ‘H NMR spectra show definite broadening of [BaHg]' due to bonding with Yb^^ ion. Based on the above observations, pyridine is a stronger base than CH 3C N and causes a cleavage of [BsHg]' to produce C 5H 5NBH 3. The other expected cleavage product [BzHs]' was not observed.
Separation of (CsH 5N)xYb[B3H8]2 from the CsHsNBHs and (C;H5N)xYb[BH4]2 mixture was not successful.
5. (THF)xYb[B3H8]2.5
Displacement of NH 3 from (NH3)%Yb[B3H8]2 with THF and subsequent filtration yielded a light yellow-green filtrate of (THF)xYb[B 3H8 ]2. Slow removal of THF at 0 ®C under vacuum yielded yellow-green crystals. Removal of THF, washing with hexane and vacuum-drying gave a yellow solid, (THF)o^Yb[B 3H8 ]2, whose formula was determined by elemental analysis. The ' ‘B and H NMR spectra of crystals of 5 in
THF were taken at 213 K. The '^B NMR spectrum consists of a broad singlet at -30.1 ppm and a quintet at -34.5 ppm (Jbh = 79 Hz) (fig. 20). All "B nuclei of 5 are equivalent indicating fluxional behavior. The H NMR spectrum consists of a broad singlet at 0.19 ppm (fig. 21). The '^B NMR spectrum confirms that the crystals are mixtures of (THF)*Yb[B3H8]2 and (THF)*Yb[BH 4]2. This might explain the difficulty of obtaining a single crystal of (THF)%Yb[B3H8]2. (THF)xYb(BH 4]2 formed from KCBHt], that was not effectively removed from the starting material, K[B 3H8 ] (eqn. 2).*^^
40 3S3K
333K
293K
283 K
273K
263K
2S3K
243 K
233K 'TI r I • ' ■5•10 •15 ■20 ■25 -30 -35 Bpm
Figure 18. Variable temperature (233 K to 353 K) 160 MHz NMR spectra of (CsHsN),Yb[B3H,]2, 4, in C sD jN .
41 353K
A_ 333K
_ > v A . 293K
; J 283 K i 273 K J 263K
J L_ 253 K
J; 243 K
u \__ 233K
I I I I 1...... 1...... 1...... 1...... 1...... 1...... 1...... 1...... 1...... 1...... r I...... I" 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 *4 -5 -S *7 -8 *9 ppn
Figure 19. Variable temperature (233 K to 353 K) 500 MHz ‘H NMR spectra of (CîH5N)«Yb[B3H8 ]2. 4, in C5D5N.
42 2K/Hg + 4 BH3THF— KIBH4I + K PsH j (2)
According to the literature method, K/Hg and B H 3T H F were reacted in a 1 to 3 ratio and excess B H 3T H F was removed under dynamic vacuum. K [B H 4], which should be removed by filtration, is slightly soluble in T H F and therefore contaminates the starting material, K[B3Hg]. [BH4]' was also observed in the ' B N M R spectrum of
(C;H5N)xYb[B3Hg]2, 4. The N M R of 5 contains a singlet at 0.60 ppm due to
43 16 -18 -20 -22 -24 -26 -28 -30 -32 -34 -36 -38 -40 -42 ppm
Figure 20. 160 MHz “B NMR spectra of crystals of (THF)*Yb[B 3H8 ]2, 5, in rf«-THF at 213 K.
44 JU.
1 I jiJUV I" ' I T ----- 1----- r —I -----1— —|— —I ---- 1 6 4 2 0 -2 -4 “6 -8 ppm
Figure 21. 500 MHz ‘H NMR spectra of crystals of(THF)xYb[B 3Hg] 2, 5, in rf«-THF at 213 K.
45 6. The formation of clusters
The formation of larger boron cages &om an acetonitrile solution or an acetonitrile/hexane layer of (CH 3CN)*Yb[B 3H8 ]2, 1, was a puzzle. This puzzle may be explained by “ B NMR spectrum of crystals of (THF)%Yb[B 3Hg ]2 in dg-THF, which contains a significant amount of [EH»]* in the solution of (THF)xYb[B3Hg] 2, 5. This suggested the possibility of the conversion of stable [B 3Hg]' into a larger cage. Thermal conversion of (CH3CN)4Yb[B3Hg] 2, 1 into 311 or 312 cages was attempted. The
CH3CN solution of 1 was heated at 40 for 4 hours, 60 °C for Ih and 3h, 75-78 °C for
23 hours, and 101 °C for 19 h 30 min. Each time, the acetonitrile solution was cooled to room temperature and an " 3 NMR spectrum was taken (fig. 22). After heating, the ' *3 resonance for 1 is unchanged, that is the chemical shift remains constant. No new resonances due to larger borohydride cage clusters were observed. Thus, no thermal conversion of (CH3CN)4Yb[33Hg] 2, 1, into larger cage clusters occurred. Therefore, it seems that the formation of clusters requires a [3 H4]'.
46 After heating at 374 K for 19.5 h
A
After heating at 348-351 K for 23 h
After heating at 333 K for 3 h
After heating at 333 K for 1 h
After heating at 313 K for 4 h
"1 1" "I ...... I" • I I " I...... 1...... I 40 30 20 10 0 - 1 0 -20 -30 ppm
Figure 22. 80 MHz "B NMR spectra of an CHjCN solution of(CH 3CN)4Yb[B3Hg] 2, 1, after heating at different temperatures.
47 7. (CH3CN)*E u[BjH8]2.6
In a similar approach to the synthesis of (NH 3)xYb[B3H8 ]2, the light yellow-green
(NH3)xEu[B3Hg ]2 complex was prepared from the metathesis reaction between
(NH3)xEuCl2 and KIB 3H8 ] with a 1 to 2 molar ratio in liquid NH 3 (eqn. 3).
(NH3)xEuCl2 + 2K[B3Hg]— ------► (NH3)xEu[B3H8]2 + 2KC1 (3)
Displacement of liquid NH3 with C H 3C N and subsequent filtration of the reaction mixture yielded a brilliant yellow-green filtrate and KCl, identified by X-ray powder diffraction studies. Removal of C H 3C N under dynamic vacuum resulted in a pale green solid, which was washed and vacuum-dried and was determined to be
(CH3CN)o.iEu[B3H8]2 by elemental analysis. The color of the complex is the same as that observed for the Eu(ll) complexes of [BioHio]^*, [BioHh]^* and [BH»]* in CH 3C N .^’’
36, 28 , 29 gÎQgg most of the acetonitrile can be removed under dynamic vacuum, this complex can function as a good precursor to the lanthanide boride, EuBg. Because of paramagnetic nature of Eu(ll) ion, the "B NMR spectrum was silent, which supports the fact that [B 3H8 ]' is bonded to the Eu(ll) ion.
8. [E u(NH3)6(CH3CN)3][B3H8]3, 7
Colorless crystals of [Eu(NH3)g(CH 3CN)3][B3H8 ]3, 7 were grown by slow
removal of C H 3C N from an accidentally oxidized solution of (CH 3CN)xEu[B3H8 ]2. The
crystal structure was solved by Dr. Shengming Liu. Crystallographic data for 7 are
reported in Table 7. Atomic coordinates for 7 are given in Table 8. Bond lengths and
angles for 7 are listed in Table 9. 7 crystallizes in the hexagonal space group, P 63/m. It
exists as the discrete [Eu(NH 3)6(CH3CN)3]^^ cation and three [B 3H8 ]* anions. The 48 molecular structure of [Eu(NH3)6(CH3CN)3]^^ is shown in figure 23a. The Eu(m) is on a special position which has a 3-fold rotation axis and a mirror plane. Unlabeled atoms of N H 3 and C H 3C N are symmetrically generated fix>m N 2, Nl, Cl 1 and €12. All three
C H 3 C N molecules are in the horizontal mirror plane. The Eu(in) ion is nine-coordinate with a tricapped trigonal prismatic coordination geometry. The comers of trigonal prism are formed by six N H 3 ligands and the three C H 3 C N ligands cap the faces of the trigonal prism. The molecular structure of [B3Hg]' is shown in figure 23b. The distance between
B1 and B 2,1.74(1) Â, which has a hydrogen bridge, is surprisingly comparable to the distance between B1 and B1 A, 1.72(2) Â, which has a direct B-B bond. This is contrary to the structure of Cs[B3Hg]. In CsPsHg], the distance between borons which are connected by a hydrogen bridge, 1.78(1) A, is shorter than the distance between boron atoms that are directly bonded, 1.83(1) A.‘*‘ To prevent the solubilization of KCl in
C H 3C N , short stirring times of the solid were employed and this resulted in the incomplete displacement of N H 3 with C H 3 C N . The ‘*B {*H} NMR spectrum of this oxidized Eu(UI) complex shows a broad singlet at -26.5 ppm (fig. 24). The broad resonance is due to the influence of the paramagnetic Eu(m) ion. All “ B nuclei are equivalent due to the fluxional behavior of 7.
The metathesis reaction between EuCb and K[B 3Hg] with a 1 to 3 molar ratio in
C H 3 C N at room temperature was performed to synthesize [Eu(CH3CN)x][B3Hg]3. This synthesis did not work due to the very low solubility of EuCb in C H 3C N .
49 (a)
«I Wl,
HOC HI3
HIM ■U
HU HIM
(b)
Figure 23. (a) Molecular structure of [Eu(NH3)6(CH3CN)3]^^ and (b) molecular structure of[B3Hg]'.
50 Figure 24. 80 MHz 'B {‘H} NMR spectrum of [Eu(NH3)6(CH3CN)3][B3H8 ]3, 7, in CH3CN.
51 empirical formula CisHi02Bi8BU2N20 formula weight, amu 1073.68
space group PSa/m a , A 14.2797(10) b , A 14.2797(10)
c, A 0.8740(10) a, d e g 90 P , d e g 90 Y , d e g 120 vol, A^ 1567.1(2)
Z 1
p (calcd), mg m*^ 1.138
crystal size, mm 0.38 X 0.15 X 0.06
T, °C -100 radiation (X,A) MoKa (0.71073) (1, mm'^ 2.014 scan mode u at 55/-S5
26 lim its , deg 5.66 - 50.02 ±h -16, 15 -15, 16 ±1 - 1 0 , 10 no. of rfln s measd 23062
no. of unique rflns 983
no. of variables 77
J?i* [I>2a(I)l 0.0385
wüj*’ (a ll data) 0.0863
GooF 1.237
• JÎ2 = SI |Fo|-|Fcl 1/SIFol
^ wi?2 = (S[w(Fo"-Fc*)*]/S[w(Fo*)*]}'/*
Table 7. Crystallographic data for [Eu(NH3)6(CH3CN)3][B3H8]3,7.
52 Atom X Y z U(eq)*
Eu(l) 6667 3333 7500 47(1) N(l) 8312(5) 5282(5) 7500 68(2) N(2) 5475(3) 1946(3) 5504(4) 65(1) C (ll) 8987(7) 6139(7) 7500 80(2) C(12) 9930(20) 7237(17) 7500 184(13) B(2) 10976(10) 4505(10) 7500 95(3) B(l) 10575(7) 3298(9) 6537(10) 101(3) N(1A) 10000 10000 5000 200(40) C(2) 10000 10000 7500 120(30) C(l) 10000 10000 6250(100) 240(20)
• U(eq) is defined as one third of the trace of the orthogonalized Uij tensor.
Table 8. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ x 10^) for [Eu(NH3)6(CH3CN)3][B3Hg] 3, 7,
53 Bond Lengths Eu(l)-N(2)#l 2.566(4) C(12)-H(12A) 0.65(9) Eu(l)-N(2) 2.566(4) B(2) -B(l) 1.744(14) Eu(l)-N(2)#2 2.566(4) B(2)-B(l)#3 1.744(14) Eu(l)-N(2)#3 2.566(4) B(2)-H(22) 1.09(8) Eu(l)-N(2)#4 2.566(4) B(2)-H(21) 1.12(10) Eu(l)-N(2)#5 2.566(4) B(2) -H(13) 1.50(11) Eu(l)-N(l)#5 2.593(6) B(l)-B(l)#3 1.709(17) E u (l)-N (l) 2.593(6) B(l)-H(12) 1.30(7) Eu(l)-N(l)#2 2.593(6) B (l) -H ( ll) 1.01(10) N(1)-C{11) 1.117(9) B(l)-H(13) 1.29(10) N(2)-H(2A) 0.9099 N(1A)-C(1)#6 1.11(9) N(2)-H(2B) 0.9100 N(1A)-C(l) 1.11(9) N(2)-H(2C) 0.9101 C (2)-C (l) 1.11(9) C(ll)-C(12) 1.47(2) C(2) -C (l)#3 1.11(9) C(12)-H(12B) 0.93(8)
Angles N(2)#l-Eu(l)-M(2) 137.58(7) N(2)#3-Eu(l)-N(l)#2 68.24(13) N(2)#l-Eu{l)-N(2)#2 87.29(18) N(2)#4-Eu(l)-N(l)#2 69.34(13) N(2)-Eu(l)-N{2)#2 77.61(14) N(2)#5-Eu(l)-N(l)#2 69.34(13) N(2)#l-Bu(l)-M(2)#3 77.61(14) N(l)#5-Eu(l)-N(l)#2 120.000(1) N(2)-EU(1)-N(2)#3 87.29(18) N(l)-Eu(l)-N(l)#2 120.0 N(2)#2-Eu{l)-N(2)#3 137.58(7) C(ll)-N(l)-Eu(l) 176.6(7) N(2)#l-Eu(l)-N(2)#4 77.61(14) Eu(l)-N(2)-H(2A) 109.5 N(2)-Eu(l)-N(2)#4 137.58(7) Eu(l)-M(2)-H(2B) 109.5 N(2)#2-EU(1)-N(2)#4 137.58(7) H(2A)-N(2)-H(2B) 109.5 N(2)#3-Eu(l)-N{2)#4 77.61(14) Eu(l)-N(2)-H(2C) 109.5 N(2)#1-EU{1)-N(2)#5 137.58(7) H(2A)-N(2)-H(2C) 109.5 N(2)-Eu(l)-N(2)#5 77.61(14) H(2B)-N(2)-H(2C) 109.5 N(2)#2-Eu(l)-N(2)#5 77.61(14) N(l)-C(ll)-C(12) 176.0(17) N(2)#3-Eu(l)-N(2)#5 137.58(7) C(11)-C(12)-H(12B) 108(5) N(2)#4-Eu(l)-N(2)#5 87.29(18) C(11)-C(12)-H(12A) 89(10) N(2)#l-Eu(l)-N(l)#5 68.24(13) H(12B)-C(12)-H(12A) 85(7) N(2)-Eu(l)-N(l)#5 69.34(13) B(l) -B(2)-B(l)#3 58.7(8) N(2)#2-Eu(l)-N{l)#5 68.24(13) B(l)-B(2)-H(22) 117(4) N(2)#3-Eu(l) -N(l)#5 69.34(13) B(l)#3-B(2)-H(22) 117(4) N(2)#4-EU{1)-N{1)#5 136.35(9) B(l)-B(2)-H(21) 102(4) N(2)#5-EU(1)-M(1)#5 136.35(9) B(l)#3-B(2)-H(21) 102(4) N(2)#l-Eu(l)-N(l) 69.34(13) H(22)-B(2)-H(21) 134(6) N(2)-Eu(l)-N(l) 136.35(9) B(l)-B(2)-H(13) 46(4) N(2)#2-EU(1)-N(1) 69.34(13) B(l)#3-B(2)-H(13) 101(4) N(2)#3-Eu(l)-N(l) 136.35(9) H(22)-B(2)-H(13) 83(4) N(2)#4-EU(1)-N(1) 68.24(13) H(21)-B(2)-H(13) 112(4) N(2)#5-Eu(l)-N(l) 68.24(13) B(l)#3-B(l)-B(2) 60.7(4) N(l)#5-Eu(l)-N(l) 120.000(1) B(l)#3-B(l)-H(12) 104(3) N(2)#l-Eu(l)-N(l)#2 136.35(9) B(2)-B(l)-H(12) 110(3) N(2)-EU(1)-N(1)#2 68.24(13) B(l)#3-B(l)-H(ll) 123(6) N(2)#2-EU(1)-N(1)#2 136.35(9) B(2)-B(l)-H(ll) 111(5)
(to be continued)
Table 9. Bond lengths (A) and angles O for |TEu(NH 3)6(CH3CN)3][B3H8 ]3, 7. 54 Table 9. (continued)
H(12)-B(1)-H{11) 128(6) C(1)#6-N(1A)-C(l) 180.00(5) B(l)#3-B(l)-H(13) 113(5) H(ll)-B(l)-H(13) 1 0 0 ( 6 ) B(2)-B(l)-H(13) 57(5) C(l)-C(2)-C(l)#3 180.00(6) H(12)-B(l)-H(13) 78(5) N(1A)-C(l)-C(2) 180.0
Symmetry trauisformations used to generate equivalent atoms: #1 -y+l,x-y,-z+3/2 #2 -y+l,x-y,z #3 x,y,-z+3/2 #4 -x+y+1,-x+1,-z+3/2 #5 -x+y+1,-x+1,z #6 -x+2,-y+2,-z+1
55 9. (THF)4Yb[(n.H)2BCgHM]2,8
(THF)4Yb[(n-H)2BC8Hi4]2 .8 was prepared via the metathesis reaction between
(THF)xYbCl2 and K^BCgHw] with a I to 2 molar ratio in THF at room temperature
(eqn. 4),
(THF)xYbCl2 + 2 K[H2BCaHi4] IÜL—► (THF)4Yb((|i-H)2BC0Hi4]2 + 2 KCl (4)
The reaction mixture was an orange-brown suspension. Subsequent filtration yielded an
orange-yellow-brown filtrate. Slow removal of THF at 0 °C under vacuum gave yellow
thin-plate like crystals. The color of the crystal is the same as that of (THF)xYb[B 3Hg] 2,
S. The crystal structure was solved by Dr. Shengming Liu. Crystallographic data for 8
are given in Table 10. Atomic coordinates for 8 are given in Table 11. Bond lengths
and bond angles for 8 are listed in Table 12. The molecular structure of 8 is shown in
figure 25. 8 crystallizes in the triclinic space group, P1. Yb(H) ion is eight-coordinate
with four bridging hydrogens from two [H 2BC8 H14]' anions and four oxygens from THF.
The coordination geometry of the Yb^^ ion is a distorted square antiprism. The two
[H2BCgHi 4]' anions bond to the Yb(II) ion through three-center two-electron B-H-Yb
bonds. The distances between ytterbium and bridging hydrogens are 2.1(2) Â, 2.50(7)
A, 2.3(1) A and 2.0(1) A with the average Yb-H distance is 2.2(3) A. This average is
comparable to those observed in (CH3CN)6Yb[(p-H)2BnHit], 3 (2.50(3) A),
((CH3CN)6Yb[(p-H) 2BioHi2l* 2CH3CN (2.3(1) A) and (CH3CN)4Yb[(ii-H)3BH]2 (2.4(1)
27,28 ,29 RemQval of THF, washing with hexane and vacuum-drying gave the yellow
solid, Yb[H 2BCgHi 4]2> determined by elemental analysis. The ^ *B NMR spectrum of the
yellow solid in
chemical shift is about 3.9 ppm downfield fiom the signal of K[H 2BCgHi 4] at -16.3 ppm 56 (Jbh = 74 Hz) in THF. The downfield shift and smaller coupling constants imply that
[H2BCgHt 4]' is bonded to the ion. This shift is not as dramatic as when
[HzBCgHi#]' bonds to a transition metal ion. This was also observed in Yb(II) complexes of [BH»]' and [BioHh]^'.^’’^*’^ Apparently both "B nuclei are equivalent since there is only one resonance.
The metathesis reaction between (Et20)xYbCl2 and K[H 2BCgHi 4] with a 1 to 2 molar ratio in ether at room temperature was not successful because of the very low solubility of YbCU in ether.
10. Hydride ion abstraction reaction from (THF) 4Yb[(p-H) 2BCgHi 4]2, 8, with B(C 6p 5)3
Bridging hydride ion can be abstracted from (THF) 4Yb[(p-H) 2BCgHi 4]2 by the strong Lewis acid, B(C 6Fs)3. The reaction of (THF)4Yb[(p-H)2BCgH,4]2,8, with
B(C6p 5)3 in a 1 to 1 molar ratio yielded [(THF)*Yb{(p-H)2BCgHi4}r[HB(C6F5)3]‘, 9
(eqn. 5).
(THF)4Yb[(|i-H)2BC8H,4]2 + B{C^Fsh ((THFl^YtKCp-HlzBCeHMiriHBfCeFsy-
+ 1 /2 (ji-H)2(BC8Hi4)2 (5)
The "B NMR spectrum of the reaction mixture consists of a triplet at -9.6 ppm (Jbh = 68
Hz) and a doublet at -25.4 ppm (Jbh = 91 Hz) (fig. 27). The triplet corresponds to
[(THF)xYb{(p-H) 2BCgHi 4}]^ and the doublet to the anion, [HB(C 6F5)3]‘. The triplet is shifted about 2.8 ppm downfield from the resonance of 8 at -12.4 ppm. The formation of (p-H) 2(BCgHi 4)2 is verified by the resonances at 27.7 ppm [(p-H) 2(BCgHi 4)2] and at
13.7 ppm [HBCgHi 4*THF]. The cationic complex may function as a catalyst for the polymerization of C 2H4 or propylene oxide because of the lability of the solvent ligands.
57 C127
C123
Figure 25. Molecular structure of (THF)4Yb[(p-H) 2BCgHi 4]2, 8.
58 T T T T I—'—r~ 1—'—r— TT 4 2 0 2 4 6 ■8 -10 •12 - 1 4 p p m
Figure 26. 80 MHz “B NMR spectra of (THF) 4Yb[(n-H)2BCgHi 4]2, 8 in
59 empirical formula CazHgoB^O^Yb
formula weight, amu 703.46
space group PI
a, Â 9.8616(10)
b, k 10.2266(10)
c, Â 10.4760(10)
a, deg 69.873(10)
P, deg 76.629(10)
y, deg 66.116(10) vol, k^ 901.83(15)
Z 2
p (calcd), mg m"' 1.295
crystal size, mm 0.73 X 0.23 X 0.08
r , “C -3
radiation {k,k) MoKa (0.71073) fi, mm'*^ 2.622 scan mode a a t S5/-55
26 lim its , deg 4.54 - 50.16
±h - 11 , 11 ±k - 12 , 12 ±1 - 1 2 , 12 no. of rfln s measd 6128
no. of unique rfln s 6128
no. of varicibles 360
Ri* [r>2o(I)l 0.0398
wRg^ (a ll data) 0.0953
GooP 1.048
* = SI IFol-lFcll/SIFol *> wR; = {Stw(Fo*-Fc*)*]/E[w(Fo*)*l
Table 10. Crystaiiographic data for (THF) 4Yb[(p-H) 2BCgHi 4]2, 8.
60 Atom X y z U(eq)‘
Yb(l) 15350(1) 7443(1) -9831(1) 68(1) B 1) 13320(30) 9900(30) -11470(30) 85(8) C 111) 11950(40) 10110(30) -12310(50) 190(16) C 112) 11970(20) 10180(20) -13560(20) 106(5) C 113) 12380(40) 11160(70) -14360(40) 220(20) c 114) 13740(50) 11840(50) -13780(40) 190(20) c 115) 13450(20) 11620(20) -12500(40) 139(12) c 116) 12090(30) 12720(30) -12090(20) 113(8) c 117) 10920(60) 12640(40) -12010(50) 340(30) c 118) 10460(30) 11020(30) -11740(20) 99(7) B 2) 17360(30) 4980(30) -7950(20) 70(7) C 121) 18888(18) 5000(17) -7640(18) 84(4) C 122) 18230(60) 4610(40) -5890(40) 280(30) C 123) 18120(40) 3130(30) -5220(20) 146(13) C 124) 17210(40) 3060(30) -5650(30) 121(7) c 125) 17330(30) 3410(20) -7340(18) 131(12) c 126) 18670(30) 2290(30) -8110(30) 116(8) c 127) 20200(12) 2145(16) -7567(16) 91(3) c 128) 20190(20) 3600(30) -8200(30) 116(8) 0 1) 15268(19) 8923(14) -8468(12) 115(5) 0 2) 15097(12) 5607(12) -10698(13) 92(3) 0 3) 17412(11) 7808(16) -11471(15) 107(5) c lA) 14920(40) 11250(40) -7970(30) 137(13) c IB) 15750(30) 9510(30) -6730(30) 129(12) c 1C) 14620(30) 10660(20) -8830(20) 101(10) c ID) 15030(30) 8710(20) -6980(20) 130(9) c IE) 16910(80) 10060(70) -8150(60) 290(30) c IF) 15490(40) 10400(30) -9330(30) 164(12) c IG) 17050(30) 9380(30) -8940 (40) 106(13) c 2A) 13920(30) 5880(30) -11430(30) 97(11) c 2B) 14670(40) 6230(40) -12350(30) 118(16) c 2 0 14890(60) 4080(40) -11580(30) 143(16) c 2D) 15960(50) 4310(60) -12400(50) 210(20) c 2E) 16500(30) 4700(30) -11410(30) 113(10) c 2F) 14410(30) 5210(20) -12500(20) 130(5) c 3G) 18620(30) 7900(30) -10960(20) 112(11) c 3A) 18630(80) 6610(50) -11890(50) 80(20) c 3B) 18970(70) 7270(70) -13450(60) 240(30) c 3 0 19640(60) 7210(40) -11780(50) 126(16) c 3D) 17660(30) 9220(30) -12160(30) 132(10) c 3E) 18740(50) 8520(50) -13500(40) 149(14) c 3F) 19880(60) 7240(50) -12980(50) 120(17) 0 4) 13160(20) 6842(17) -8379(15) 121(6)
(to be continued)
Table 11. Atomic coordinates ( x 10'') and equivalent isotropic displacement parameters (A^ x 10^) for (TI^4Yb[(p-H)2BCgHi4]2,8.
61 Table 11. (continued)
C(41) 11602(17) 7980(30) -8183(19) 129(8) C(42) 11110(30) 7500(30) -6870(30) 180(20) C(43) 12210(40) 6100(40) -6090(30) 240(30) C(44) 13267(14) 5910(20) -6905(16) 175(10)
* U(eq) is defined as one third of the trace of the orthogonalized Uij tensor.
62 Bond Lengths Yb(l) -0(1) 2.380(13) C 123)-H(12D) 0.9616 Yb(l) -0(3) 2.405(12) C 124)-C(125) 1.67(4) Y b (l)-0(2) 2.464(13) C 124)-H(12E) 0.9687 Yb(l) -0(4) 2.506(15) C 124)-H(12F) 0,9723 Y b (l)-B (l) 2.80(2) C 125)-C(126) 1.62(4) Yb(l)-B(2) 2.91(2) C 125)-H(125) 0.9802 Yb(l)-H(IA) 2.12(16) C 126)-C(127) 1.66(3) Yb(l)-H(IB) 2.50(7) C 126)-H(12G) 0.9644 Yb(l)-H(2A) 2.29(13) C 126)-H(12H) 0.9710 Yb(l)-H(2B) 2.01(11) C 127)-C(128) 1.40(3) B(l)-C(lll) 1.68(5) C 127)-H(12I) 0.9720 B(l)-C(115) 1.76(4) C 127)-H(12J) 0.9739 B(1)-H(1A) 0.83(16) c 128)-H(12K) 0.9719 B (l)-H d B ) 1.09(8) c 128)-H(12L) 0.9685 C(lll)-C(112) 1.29(5) 0 I)-C (ID ) 1.47(2) C(lll)-C(118) 1.50(5) 0 I)-C(IC) 1.56(3) C(lll)-H(lll) 0.9737 0 I)-C (IF ) 1.54(3) 0(112)-0(113) 1.21(6) 0 I)-C (IG ) 1.91(3) 0(112) -H(llA) 0.9715 0 2)-C(2A) 1.42(3) 0(112)-H(llB) 0.9727 0 2 ) -C(2E) 1.52(3) 0(113)-0(114) 2.02(7) 0 2 ) -C(2B) 1.71(3) 0(113)-H(llO) 0.9830 0 3)-C(3A) 1.44(6) 0(113)-H(llD) 0.9761 0 3)-C(3D) 1.47(3) 0(114)-0(115) 1.27(5) 0 3)-C(3G) 1.47(3) 0(114)-H(llE) 0.9722 c lA) -C(IC) 1.38(3) 0(114)-H(llF) 0.9615 c lA) -C(IF) 1.80(4) 0(115)-0(116) 1.45(4) c lA) -C(IE) 1.85(7) 0(115)-H(115) 0.9787 c lA)-C(IB) 1.80(4) 0(116)-0(117) 1.17(7) c IB)-C(ID) 1.39(3) 0(116)-H(llG) 0.9717 c IB)-C(IE) 1.73(6) 0(116)-H(llH) 0.9705 c 1C)-C(IF) 0.89(3) 0(117)-0(118) 1.80(6) c IE)-C(IG) 1.21(7) 0(117)-H(llI) 0.9554 c IE)-C(IF) 1.94(7) 0(117)-H(llJ) 0.9837 c IF)-C(IG) 1.52(4) 0(118)-H(llK) 0.9693 c 2A)-C(2B) 1.12(4) 0(118)-H(llL) 0.9726 c 2A)-C(2F) 1.39(4) B(2)-0(125) 1.52(3) c 2A) -C(2C) 1.74(5) B(2)-0(121) 1.63(3) c 2B)-C(2F) 1.23(4) B(2)-H(2A) 1.27(14) c 2B)-C(2D) 1.87(6) B(2)-H(2B) 1.55(12) c 2B)-C(2C) 2.00(5) 0(121)-0(128) 1.67(3) c 2B)-C(2E) 2.03(4) 0(121)-0(122) 1.76(5) c 2C)-C(2F) 1.22(4) 0(121)-H(121) 0.9796 c 2 0 -C(2D) 1.24(6) 0(122)-0(123) 1.48(5) c 2C)-C(2E) 1.99(4) 0(122)-H(12A) 1.0037 c 2D)-C(2F) 1.44(5) 0(122)-H(12B) 0.9660 c 2D)-C(2E) 1.49(4) 0(123)-0(124) 1.12(5) c 3G) - 0 (3 0 1.30(6) 0(123)-H(120) 0.9738 c 3G) -C(3D) 1.63(4)
(to be continued)
Table 12. Bond lengths (A) and angles (°) for(THF) 4Yb[(n-H)2BC8 Hi4]2, 8 .
63 OOOpQPQDODOOOOntDaDOOOOCDUOOOODDOOOOOOOOOOOOOO g ooooooooooon n s* —4»WWWWWWWWWWW maooiDBJa)>>>o w
O I I I I I I I I I I I ^ooooooooooo |||WW*)|||||W|||||||||,|||||||||||, 1,111 m m m M m m m m m # p;mP3«%«g3«m«m«wmmwmwmmwoooooo —ll^WWWWWWWWWWW n3MM*flOBl*iinaODO> I
H» H»H»H*H»H»H»H»MMMM H H H HHMH»M H» HMMH» o > 0 0 M l o o > fO a i «nI OO m w a i N> O H •sj M VD 0 0 0 0 v o \ o 0 0 v o 0 0 0 0 \ o VD KO -si u > V£> o > w a i W «O KO r o W H» M a i a i 0 0 H M a i 0 0 K ) a i H o > VD • j w WO O o > w H* a i 0 0 w lO a i o 0 0 H» a i d k M O a i o H a i a i 0 0 H» 'O W 0 0 M •o 0 0 M a i a i O u> r o WW w a i w •1^ w W W w a i o O o \ r o a i M a i a i d k d k d ^ d k 0 0 a i a i o > a i d k e o 0 0 o w W a i M w «O dk m m 0 0 * o •O • o - 0 m a i M M M H» MM M M a \ CT> crv o \ - j - J a i - J a i a i dk o > KO VD 0 0 'J 0 0 CD O I 2 S ooooowoonoowoonnownooonwKooKonnnowwacoflajo oonnnnnooooo winwininn#&kfu,(kK)po|K»wMWMMi œtoootoio'— i i i — ^ — — I I — I — ^ I I I KKK tiiiiiiiiiiiiiiii^iiiiiODoiiioo(iiiiK»<»
HH HM H H H H H H»H»H» h * H» H t * M H HM W W O b D OO 0 0 0 > > W HH 0 0 S 0000H*00H*00 HMMMMM M MM H»M H»M M H* M H*H» MMM H* M M H» H» M M H O H o OOO M OO M OO O OO H » v o VO VO M WM v o a i r o H w M r o W W KO 0 a i d k w 0 VO v o v o v o v o H KO v o 0 VO KO w 0 H KO O U) - 0 a i a i O a i v o VO 'O KO VO VO 0 0 r o 0 0 v o HH r o w w r o W o VO o O d k r o W w d k o 0 0 0 « o 0 • o - o 0 o 0 - j d k r o v o v o o d k M CD -J w KO r o H W a i 0 0 H* a i a i r o - o r o r o a i 0 0 w a i a i r o W W w H» d k d k a i MMM r o M r o d k w 0 w W w 0 0 0 0 0 0 w 0 d k d k r o o w r o o O O o H» H» M a i 0 0 0 0 wnoooowonnooooB>otBiDaBj (OtOtOeoeOtONJtOIOeOtOtOtOKJ—eO'—— sr nW i6'N)ii^i^yt-'W |-'W W Na) I CD I I tn — HU)i-*uiuips-33-'-)H**-‘MaD(naDO>o>Ou)>jut~j~j i o> o> Dd oooonoooooooooH*03-*H-.-.aitD—.œ œ m oBM ooooooooooooonoooot-'O ooooo (0(010(0(0(0(0(0(0(0(0(0(0(0 — (O —' — I I — 1 — —------(-•(-•(-•(-•(-•(-•(-‘•-•(-•HI-*h*HH(-‘ HI-*(-‘'^H(-*H(-*H*-‘ O —wwwwww(o(o(o(o(oio(-'(-' — — —------— — — — — —'S'— I (-" O( O I —S S— IS S I —S Si S i K i K i (3 iooa>aDOoa>OD-o^^-o^'Oaiaio>o>aia>iinu(U(uiu(it^ —' —' ^ —' — '— '— '— — — “ — ^ ' ' S —' — — SJ, O sss»PQnsssssossi-‘n>->i->DDio(o>MM^^i->sssssnsssssnsssssn(-‘SSDmnsI I I I I I I I I I I I I i^ i^ ^ (0 (o ^ ^ (o ^ ^ tP (P '— i I I I I I I I I I I I I I I I I i^'.i I I I I I B e r —> f r —» •—> ^ ^ r —^ f f f —» ( O r—« (O (O '—' S S y * ^ (~ * |—* ( O r —' *—> «—« -—' *—» <—• ' —* •—'» *—> *'—'« f—* f —' "—* '—- «—' '—' •—' ' ■ (-* ■ ■ ' ' ' ■ ' ' ' ' ' ' l-'l-*(-*(-*l-*l-*(-*l-*l-*i-‘ (-*i-*i-*(-‘ (-‘ l-*(oai — — — —"i-*i-‘ i-*i-*i-‘ h'i-*i-‘ i-*l-‘ i-‘ i-*(-‘ (-‘ l-‘ l-*t-‘ l-‘ (-‘ tni-‘ i-*i-‘ (-‘ H‘ (— Q. (0(0(0(0(0(0(0(0(0(010(0(0(0— (O — — — H‘ (-‘ l-*(-‘ (-‘ |-‘ |-‘ l-‘ |-‘ (-‘ |-‘ (-‘ l-‘ l-‘ H'l-‘ l-‘ |-‘ — (-•I-*— — (-*(-■ '—' OOOOOMB»M>55(-*(-*h (O P'P'fSM'JCiCiCii-ii-ioosSSmoin uiw m «n (-•(-•(-•(-•(-•HHH(-*(-*(-*(-*I-*(-*I-*I-* (-» (-" O(-*OHOOOOHOO(-'|-*(-*(-‘ |-*00Oa)rf^t0VDi»>.|-*|-‘(0(0OO|-*('*l-*H*V£)OOOOO(0OOOOO(0OOOO|-*(-‘ O CD(-‘ voooQaoijiix>o~o-o-OLn4^i(^CQU>(o-oi-‘ oa>vo>t‘ aQLoaicx)u>(o(-‘ ui(o-ouiui(jii(^-ju]cna>aia>œ (ouia\~j>(^u}>t>u> 0\0D (0«^*iD .U I(00>O 0l(0U J(-*004k(0(0(0-0>(>'C n.I^C T>0l0l-0l/IV£)00l--l0(-*<0(0>X)O >P.U lU l(0Lnl»JC n00O U IV0O |-‘ (00JU lO H »-»(-• (-• o> ui tn -j a o n O n o o O O o OO O n OO n n o o o O n 0 o n n o o 0 O O o o n 0 O O n n o O o 0 O w m 0 o OO O O w w w w w w K) r o r o r o r o r o M MH» h* M H H» H M M MMMH* M M H*M M #-» H»MHMMM t o H r o t o M H* HHHH» Q a > o > > m M> > > O a 0 o a o O o r o t o r o r o t o t o t o t o r o t o r o t o t o t o t o t o t o t o t o t o t o t o t o t o t o t o 2 2 2 X H» •o M -0 'OH OS oo m0000 O UI •s J 0 •j •si OS # A 1 1 M 0 w 0 w w 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 O o O o O O o ooooooooooooo o o # 1 1 1 1 11111111111 # 1 1 1 1 1 1 1 1 1 1 n o o o O o o O o o O o o o o O o o OO n MH n o O n O O w w w w w w w r o r o r o r o p P p P H p h* t o r o t o M M H*H» M MH» H» MMH»MH*M 0 0 0 H»M #-* 1 1 # 1 1 » # 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 r o t o r o t o r o to to to to to to to t o t o t o t o t o t o r o t o t o t o t o t o t o t o t o 000000000000 'O 'O •si •O o \ a s OS 0 0 1 0 1 1 4k 4k 4k 4k 4k O O O O o o o o o o O o 2 2 2 2 § e g e e e e e 0 o o w w w r o r o r o H» H* M H» 1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 t 1 1 1 1 1 1 1 1 « 1 1 HH H O H MH 0 0 0 H H Mo o o 0 0 o X 0 0 0 0 o 0 0 0 0 0 O 0 0 0 0 0 o 0 0 M o H*H* 0 0 0 0 0 O 2 2 t o t o t o P M P M M p M P M MH M H H* M H» MM H* H» 0 MOS HMH H» H H» t o t o ro ro t o ro t o to to to to to to to to to to to to to to totototototo o> 0 OS 0 2 r* 5 2 3 3 HH 0 0 0 2 2 0 0 nd 0 0 M H» H*H*H*MMH» H» H» MMM H» MH* M*-»H»H*#-* MH» H*H»MMH»M MM MMMM t o H t o t o 0 0 0 H HH t o • s i 4 k O O M t o W 0 - s i O UI H VOOOOOO M O H» H H» v o o #-*H»MH» O O OO H O O OOO O O H» 0 0 o > • o w • j H O 0 0 0 O 0 W r o 0 t o M 0 0 H* W•J • s i 0 0 - s i s J VOVO t o H* r o r o v o v o M O H* O W • s i 0 0 VOVO 0 • s i • s i 0 0 0 0 - s i œ 0 0 • 0 H r o 0 W t o 0 0 H W 0 0 0 t o H 0 • J 0 O 0 O t o SO t o O w H H • 0 t o r o o VO o r o 4 k w H W W VO (D t o 0 0 4 k 0 0 r o H 0 r o H • 0 w H» M M H H»MM M M M MM SD MH MH»H» M h * M H MH r o W W W • J 0 t o O 0 t o 0 0 W 0 00 00 0 2 H» H 0 M Table 12. (continued) (1C -C(IA) -C(IE) 90(3) C(2F)-C(2C) -C(2A) 53(2) (IF -C(IA) -C(IE) 64(3) C(2D)-C(2C) -C(2A) 98(3) (1C -C(IA) -C(IB) 97(2) C(2F)-C(2C)-C(2B) 35.5( 1 5 ) (IF -C(IA) -C(IB) 92(2) C(2D)-C(2C)-C(2B) 66(3) (IE -C(IA) -C(IB) 57(2) C(2A) -C(2C) -C(2B) 33.8( 15) (ID -C(IB)-C(IE) 112(3) C(2F)-C(2C) -C(2E) 92(2) (ID -CdB)-C(lA) 97.2(19) C(2D)-C(2C) -C(2E) 48(2) (IE -C(IB) -C(IA) 63(3) C(2A) -C(2C) -C(2E) 77.0( 15) (IF -C(IC) -C(IA) 102(3) C(2B)-C(2C)-C(2E) 61.1( 15) (IF -C(IC)-0(1) 72(3) C(2C)-C(2D)-C(2F) 53(3) (lA -C(1C)-0(1) 115(2) C(2C) -C(2D)-C(2E) 93 (3) (IB -C(ID)-Od) 106.4(19) C(2F)-C(2D)-C(2E) 108(3) (IG -C(lE)-CdB) 107(5) C(2C)-C(2D)-C(2B) 77(3) (IG -C(lE)-CdA) 107(5) C(2F)-C(2D)-C(2B) 41.2( 18) (IB -C(lE)-CdA) 60(3) C(2E)-C(2D)-C(2B) 73(2) (IG -C(IE)-C(IF) 52(3) C(2D)-C(2E)-G(2) 105(2) (IB -CdE)-C(lF) 90(3) C(2D)-C(2E)-C(2C) 38(2) (lA -C(lE)-CdF) 57(2) G(2)-C(2E)-C(2C) 74.8 ( 17) (1C -C(IF)-C(IG) 131(3) C(2D)-C(2E)-C(2B) 62(2) (1C -CdF)-G(l) 75(3) G(2)-C(2E)-C(2B) 55.3( 13) (IG -CdF)-G(l) 77.1(19) C(2C)-C(2E)-C(2B) 59.7( 17) (1C -C(lF)-CdA) 49(2) C(2C)-C(2F)-C(2B) 109(2) (IG -C(lF)-CdA) 97(2) C(2C)-C(2F) -C(2A) 83(2) (1) ■C(1F) -C(IA) 96(2) C(2B)-C(2F)-C(2A) 49.9( 19) (1C -C(lF)-CdE) 103(3) C(2C)-C(2F)-C(2D) 55(3) (IG -CdF)-C(lE) 39(2) C(2B)-C(2F)-C(2D) 88(3) (1) ■C(IF)-C(IE) 90(2) C(2A)-C(2F)-C(2D) 107(2) (lA -C(IF)-C(IE) 59(2) C(3C)-C(3G) -G(3) 92(3) (IE -C(IG)-C(IF) 90(4) C(3C) -C(3G) -C(3D) 95(2) (IE -C(IG) -Gd) 103(4) G(3)-C(3G) -C(3D) 56.3 (13) (IF -C(IG) -Gd) 51.9(14) C(3C) -C(3G) -C(3A) 48(2) (2B -C(2A)-C(2F) 58(3) G(3)-C(3G) -C(3A) 49(2) (28 -C(2A)-G(2) 84(2) C(3D)-C(3G) -C(3A) 85(2) (2F -C(2A) -G(2) 113(2) G(3)-C(3A)-C(3C) 90(3) (2B -C(2A)-C(2C) 86(3) G(3)-C(3A)-C(3B) 104(4) (2F -C(2A)-C(2C) 44.1(13) C(3C)-C(3A)-C(3B) 84(4) (2) ■C(2A)-C(2C) 85.7(19) G(3)-C(3A)-C(3F) 110(3) (2A -C(2B)-C(2F) 72(3) C(3C)-C(3A) -C(3F) 46(3) (2A -C(2B)-G(2) 55.7(19) C(3B)-C(3A) -C(3F) 40(3) (2F -C(2B)-G(2) 104(2) G(3)-C(3A) -C(3G) 50.0(16) (2A -C(2B)-C(2D) 96(3) C(3C) -C(3A) -C(3G) 44(3) (2F -C(2B)-C(2D) 50(2) C(3B)-C(3A) -C(3G) 109(4) (2) ■C(2B)-C(2D) 83(2) C(3F) -C(3A) -C(3G) 83(3) (2A -C(2B)-C(2C) 60(2) C(3F) -C(3B)-C(3E) 73(5) (2F -C(2B)-C(2C) 35.1(16) C(3F)-C(3B) -C(3A) 75(5) (2) ■C(2B)-C(2C) 70.8(15) C(3E)-C(3B) -C(3A) 101(5) (2D -C(2B)-C(2C) 37(2) C(3F) -C(3B)-C(3C) 33(4) (2A -C(2B)-C(2E) 91(2) C(3E)-C(3B)-C(3C) 73(4) (2F -C(2B)-C(2E) 90(2) C(3A) -C(3B)-C(3C) 45(3) (2) ■C(2B)-C(2E) 46.8(12) C(3F)-C(3C) -C(3G) 140(5) (2D -C(2B)-C(2E) 44.6(15) C(3F)-C(3C) -C(3A) 78 (4) (2C -C(2B)-C(2E) 59.2(17) C(3G) -C(3C) -C(3A) 89(4) (2F -C(2C)-C(2D) 72(3) C(3F) -C(3C) -C(3B) 30(3) 66 o o O O n o o o o O O n O O O o O o O o n O o O 4k 4k 4k w w w w w w w W w W w w w w w w w w w w w 4k 4k m O m n m DO D • d DO • d DD DO o — '—' 00 > Q • d > 1 2 I O O 6 6 6 n n n n n n O n n o n O Ô n h O n n n NJ w w 4k 4k w w w w w w w w w w w w w O a w u> w w w w *Jd •id • d • d M W t d t d MMO n n O OOO i 8 O O o g g n n n Ô o n n O o o n n O n o O O n O w w H M H w w w w w w w w w w w w w m o w w w w w w > > > w r a o O O o o a m DO DO DO DO DO 3 s I MHHH H M H r o r o VO 00 UI a \ O U) H'J w *0 O H UI vo vo UI w VO4k UI H» UI o vo o \ w o o> 'O M •o r o CO VO M *o o o \ UI m 'O W H *>1 r o vo «0 4k w 4k UI 4k o \ r o w 4k 4k 4k 4k r o m r o r o w w W W M M MM H w r o r o vo UI 3 X O O o O O X OO O o o PC O o OO m PC o n O OO 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k WW W w r o 4k r o 4k 4k W w H W MH t * r o t o t o > > > > 1 1 o O o o 1 1 n n O n O n O n 1 n O n n O n n O O 4k 4k o OO 4k 4k 4k 4k 4k 4k 4k 4k 4k 4k M 4k H 4k 4k Z 4k % w W w w W IP t o r o r o t o t o IP M M H* 4k 1 1 w r o M 1 1 X 1 X 1 1 1 1 1 1 # 1 1 # 1 1 X 1 PC 1 1 1 XX o 1 X PC PC O 1 PC PC PC PC O 1 PC PC O « 4k 4k PC PC PC IPIP 4k Z 4k Z Z" ? 4k IP 4k IPIPIPM 4k 4k IP X 4k > 4k Z w w w w r o IP r o r o r o t o w IP W H» > M w r o ± w > U DO > > CD w > > H W > W W DO DO M I-» H» M H» H* H» M H» H* M H» M M H M H H H* H H HH O o O O O r o O HH HH o O O o O O M O M HM O o> *sj «0 'O •O o VO H» O MM r o •O 00 vo VO 00 W 00 H* OO O UI vo w M w w w UI M GO o> W 4k 'J a \ o o vo 4k 00 O - J m UI w H* H* M #-* •O 00 UI 30 25 20 15 10 50 ■5 •10 -15 -20 -25 ppm Figure 27. 80 MHz ‘ NMR spectra of the reaction mixture containing [(THF)xYb{(p- H)2BCgHi4}r[HB(C6F5)3]',9. 68 I I . [(T H F )4K]2[E u { (^ .H )2BC 8 H i4}4], 10 [(THF)4K]2[Eu{(p-H)2BCgHi 4}4], 10, was synthesized via the metathesis reaction between (THF)xEuCl2 and K[H 2BCgHi 4] with a 1 to 2 molar ratio in THF at room temperature (eqn. 6). (THF)xEuCl2 + 4 KlHgBCaHid ------► ((THF)4K]2[Eu{(p-H)2BC8Hi4}4] + 2K C I (6) The crystal structure was solved by Dr. Edward A. Meyers and Dr. Shengming Liu. Crystaiiographic data for 10 are reported in Table 13. Atomic coordinates for 10 are given in Table 14. Bond lengths and angles for 10 are listed in Table 1 S. The molecular structure of 10 is shown in figure 28. 10 crystallizes in the tetragonal space group, P42/nmc. There are 4 molecules in the unit cell. Because of the high synunetry of the molecule, the actual structure can be elucidated after symmetry generation. Most of the atoms such as Kl, Eul, 01,02, Bl, Cl, and CS are on special positions. 10 is an ionic salt and consists of two [(THF) 4K]‘^ cations and a [Eu{(p-H)2BCgHi 4}4l^* anion. K.I and Kla are coordinated to four THF molecules. The anion, [Eu{(p-H)2BCgHi 4}4]^' has pseudo-tetrahedral geometry around Eu^^ ion. Each [H 2BCgHi 4]' ion coordinates to Eu I through two bridging hydrogens and overall, there are eight bridging hydrogens. The average Eu-H distance is 2.448 Â. There is a unique agostic hydrogen-Eu interaction between Eul and HI (Hla, Hlb, Hlc), the alpha hydrogen of [H 2BC8H14]*. The Eu H distance is 2.62 A, which is slightly longer than the Eu-bridging H distance (2.47(5) A). Two [(THF>4K]^ cations are close to the anion, [Eu{(p-H) 2BC8 Hi4}4]^’. There are similar agostic hydrogen-K interactions hrom the other alpha hydrogens of [H 2BCgHur> as shown between Kl and H5, H5A, Kla and H5b, HSc and the K H distance is 2.66 A. 69 The metathesis reaction between (Et20)xEuCl2 and with a 1 to 2 molar ratio in ether was not successful due to the very low solubility of EuCh in ether. Figure 28. Molecular structure of [(THF)4K]2[Eu{(n-H)2BCgHi 4}4], 10. 70 em pirical formula CMHi2gB*EUK20; formula weight, amu 1299.06 space group P4z/nmc a ,  13.4390(19) b, A 13.4390(19) c , A 20.421(4) a, d e g 90 P , d e g 90 V, d e g 90 v o l , A^ 3668.2(4) Z 4 p (calcd), mg m'^ 1.170 crystal size, mm 0.35 X 0.31 X 0.31 T, °C -33 radiation (X,A) MoKa (0.71073) fj, mm'*^ 1.009 sc c u i m ode w at S5/-55 26 lim its, deg 5.02 - 50.06 ±h -15, 15 ±k -15, 15 ±1 -24, 24 no. of rflns measd 24113 no. of unique rflns 1782 no. of variables 104 fii* [I>2o(D ] 0.0477 wRg’ (all data) 0.1598 GooF 1.087 * = SI IFol-lFcl l/SIFol " wRi = (S[w(F/-Fe')^l/S[w(F/)'] Table 13. Crystaiiographic data for [(THF)4K]2[Eu{(p-H)2BCgHi4}4], 10. 71 Atom X y z U(eq)* E nd ) 7500 2500 2500 67(1) K (l) 7500 2500 389(1) 90(1) 0(1) 6232(g) 2500 -737(3) 152(2) C (ll) 3316(8) -945(13) 3945(8) 261(7) C(I2) 2993(11) -583(12) 3328(5) 310(11) 0(2) 5497(4) 2500 4702(4) 162(3) C(22) 3993(7) 2036(11) 4341(6) 272(10) C(21) 4903(7) 1737(10) 4563(10) 363(12) B (l) 5879(8) 2500 1628(5) 109(3) C (l) 5153(7) 2500 2226(5) 124(3) C(2) 4529(7) 1543(11) 2233(8) 264(7) C(3) 4002(11) 3643(10) 1609(12) 290(11) C(4) 4494(14) 3321(19) 1009(11) 408(19) C(5) 5150(12) 2500 1016(7) 323(16) * U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. Table 14. Atomic coordinates ( x 10'*) and equivalent isotropic displacement parameters (A^ x 10^) for [(THF)4K]2[Eu{(p-H)2BCgHi4}4], 10. 72 Bond Lengths Eu(l}-B(1}#1 2.815(9} 0(2}-C(21} 1.330(14} E u(l}-B (l} 2.815(9} 0(2}-0(21}#8 1.330(14} Eu(l}-B(l}#2 2.815(9} 0(2}-K(l}#l 2.699(6} Eu(l} -B(l}#3 2.815(9} C(22}-C(22}#8 1.25(3} Eu(l}-C(l}#l 3.203(9} C(22}-C(21} 1.364(14} E u(l}-C (l} 3.203(9} C(22}-H(22A} 0.9700 Eu(l}-C(l}#2 3.203(9} C(22}-H(22B} 0.9700 Eu(l}-C(l}#3 3.203(9} C(21}-H(21A} 0.9700 E u(l}-K (l} 4.312(3} C(21}-H(21B} 0.9700 Eu(l}-K(l}#l 4.312(3} B(l} -0(1} 1.563(15} Eu(l} -HA 2.47(5} B(l} -0(5} 1.587(15} K(l} -0(2}#1 2.699(6} B(l} -HA 1.07(5} K(l}-0(2}#2 2.699(6} 0(1}-0(2} 1.535(12} K (l}-0(1} 2.861(7} 0(1}-0(2}#8 1.535(12} K(l}-0(1}#3 2.861(7} 0 (1 }-H(l} 0.9800 K(l}-B(l}#3 3.339(11} 0(2}-0(3}#8 1.48(2} K (l}-B (l} 3.339(11} 0(2}-H(2A} 0.9700 K(l}-C(5}#3 3.407(17} 0 (2 }-H(2B} 0.9700 K(l}-C(5} 3.407(17} 0(3}-0(4} 1.46(3} 0(1}-C(11}#4 1.332(11} 0(3}-0(2}#8 1.48(2} 0(1}-C(11}#5 1.332(10} 0(3} -H(3A} 0.9700 C(ll}-0(1}#6 1.332(11} 0(3} -H(3B} 0.9700 C(ll}-C(12} 1.419(14} 0(4}-0(5} 1.41(2} C(11}-H(11A} 0.9700 0(4} -H(4A} 0.9700 C(ll} -HdlB} 0.9700 0(4}-H(4B} 0.9700 C(12}-C(12}#7 1.33(3} 0(5}-0(4}#8 1.41(2} C(12} -H(12A} 0.9700 0 (5 }-H(5} 0.9800 A ng les B(l)#l-Eu(l)-B(l) 113.6(2) C(1}#1-BU(1}-C(l}#2 159.9(4} B(l)#l-Eu(l)-B(l)#2 101.5(5} C(l}-Eu(l}-C(l}#2 91.75(7} B{l)-Eu(l)-B(l)#2 113.6(2} B(l}#l-Eu(l}-C(l}#3 96.35(14} B(l)#l-Eu(l)-B(l)#3 113.6(2} B(l}-Eu(l}-C(l}#3 130.7(3} B(l)-Eu(l)-B(l)#3 101.5(5} B(l}#2-Eu(l}-C(l}#3 96.35(14} B{l)#2-Eu(l)-B(l)#3 113.6(2} B(l}#3-Eu(l}-C(l}#3 29.2(3} B{l)#l-Eu(l)-C(l)#l 29.2(3} C(l}#l-Eu(l}-C(l}#3 91.75(7} B{l)-Eu(l)-C(l)#l 96.35(14} C(l}-Eu(l}-C(l}#3 159.9(4} B{l)#2-Eu(l)-C(l)#l 130.7(3} C(l}#2-Eu(l}-C(l}#3 91.75(7} B{l)#3-Eu(l)-C(l)#l 96.35(14} B(l}#l-Eu(l}-K(l} 129.3(2} B(l)#l-Eu(l)-C(l) 96.35(14} B(l}-Eu(l} -K(l} 50.7(2} B{l)-Eu(l)-C(l) 29.2(3} B(l}#2-Eu(l} -K(l} 129.3(2} B(l)#2-Eu(l)-C(l) 96.35(14} B(l}#3-Eu(l} -K(l} 50.7(2} B(l)#3-Eu(l)-C(l) 130.7(3} C(l}#l-Eu(l}-K(l} 1 0 0 . 1 (2 } C(1)#1-EU(1)-C{1) 91.75(7} C(l}-Eu(l} -K(l} 79.9(2} B(1)#1-EU(1)-C(1)#2 130.7(3} C(l}#2-Eu(l} -K(l} 1 0 0 . 1 (2 } B(l)-Eu(l)-C(l)#2 96.35(14} C(l}#3-Eu(l} -K(l} 79.9(2} B(l)#2-Eu(l)-C(l)#2 29.2(3} B(l}#l-Eu(l} -K(1}#1 50.7(2} B(l)#3-Eu(l)-C(l)#2 96.35(14} B(l}-Eu(l} -K(1}#1 129.3(2} (to be continued) Table 15. Bond lengths (A) and angles (®) for [(THF) 4K]2[Eu{(fi-H)2BC8 Hu}4], 10. 73 OJ » o o CM CM o f-4 vo t—4 rH VOVOcr» rH in C\ vo00 ro rH a s OS in in rH m in in in in œ rH rH rH rH in m r * r** rH mmro COin M* rH rH rH rH a \ ro ro 0000 in ro CO CO ro ro ro in in in a s fO a s a s O T j* ^ vo o o o o 00 r * OO OO GO o in in r - o o o O GO CMo \ o \ a \ a \ r ~ ro a \ r ~ r - GO 0 0 O rH a \ fO o o CMCMrH t* - in m 0 0 0 0 o r 4 r 4 rH rH o o rH rH rH rH o o CMCM o rH rH rH rH o rH O O o o o o GO vo r ~ r ~ GO rH rH VOvo rH rH rH CMCM VOo o o rH o o 1—1 r 4 r 4 I—1 rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH U) < m rH < ax f t t m axrH CM CM m GO 4 k rH CM CM CQ CQ (N r 4 < r 4 m rH rH rH < rH m CM 4 k rH CM CM < CM CQ CM < CQ rH iH f—1 f-4 r 4 rH rH CM CM rH 4 k rH CM CM CM < : rH CQ rH CM GO rH < r 4 rH u s rH 53 rH rH U 53 CM 53 CM CM H CM rH CM 4 k rH rH H CM o tn tn tn 1 t 1 53 CM rH h d 1 i 1 53 CM CM CM 53 rH rH rH rH P rH rH t 1 t c t t s a: I t S s 53 1 53 53 1 in rH rH CM rH CQ M rH 53 rH O 53 N 1 1 OI CM 1 CM 1 U 5 CM CM 1 CM I U 53 1 53 1 0 k d s s 3 1 p t P I 53 1 1 H rH rH rH rH rH rH CM I # CM CM CM CM CM 1 1 1 rH U uxCQ tn kd 1 3 3 t 3 o CQ M 53 53 1 W H r 4 iH rH rH rH CM CM rH CM CM CM rH rH CM 1 t 1 1 1 1 1 I 1 1 rH I rH t 1 rH 1 CM CM 1 O r 4 rH a u rH u rH CM CM o U a CM Ü CM rH rH CM rH CM rH rH rH I O o u u 1 1 1 u 1 1 1 1 U CM CM CM U rH rH rH rH rH rHrH rHrHrH o rH o rH rH o rH CJU CM II u 1 u 1 r- u r* o 1 OO GO GO GO Ü 00 U 1 U O 1 CQ CQ ## 1 U 1 t VOvo I vo 1 4 k 4 k 1 4 k 1 1 1 4 k 4 k 4 k 1 4 k 1 OU 1 U 1 CQCQCQaxCQ 1 CQCQ t CQu u 00 o 00 u o GO o t 00 CO U 4 k 4 k 4 k < < < 1 1 1 < 1 1 1 1 I 1 I 1 1 1 4 k 1 4 k 1 1 4 k t 4 k 4 k 1 CM CM H CM CM rH CM rH CM rH rH rH CM CM rH CM rH CM CM CM rH rH rH r 4 f—1*-4 rH rH rH rH rH rH rH rH rH CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM rH rH in rH in rH in rH CM CM CM CM CM rH CM CM rH CO ro rH d y u u uo o u o u » u u u o u 53U U UU O Ü a U 53O O U O O 53a u O o U CQ u U k<3 U U u u U m o u CQ è S O O u ÎÎ y * ro ro ro ro r » r- in in vo Vo CM m m CM •4* ro r f ro ro rH rH rH rH rH rH rH rH rH rH rH rH rH rH N CM CM CM CM CM rH rH rH rH rH rH rH rH rH rH ro ro CM CM CM CM ro ro ro ro ro ro ro fO ro CM CM T f OO GO GO GO 000 0000 m ro 4* 4* 4* r- ro as rH as rH O CM ro VO m o>r- rH CM 00 rH 00 GO 00 GO rH asas GO asasr* GO in Tf d* vo tn CM r~ d* in V£> r- CM 00 as as 4»P- asas o asasO asO O O CM in rH r * CM r* o\ in CM vn VO vo VO ro CM CM in CM CM CM CM in rH rH rH 00in r- 00 rH rH in aya>r- in ro ro CO ro OO f - in CM O r- O OO O CM ro asr- rH rH ro r- GO CO CO GO asasr- O as asO r* GO asas r~ CM o as asr ~ o CM ro as as 4* 4» 4* sovr> rH rH rHrHrH rH rHrH rH rH rH rH rH rH rH rH rHrH rH rHrH rH rH rH rH rH 4k 4k 4k 4k 4k CM ro ro ro ro ro ro ro CO ro rH rH 4 k 4 k 4 k 4 k 4 k 4 k 4 k 4 k 4 k 4 k rH rH rH 4 k rH rH 4 k ro ro ro ro rH rH rH rH rH < â < < < < CM rH rH rH rH 4 k rH rH 4 k rH rH rH rH rH in tn 4 k in in 4 k in in in in in tn 2 rH kc3kd rH 3 3 3 3 3 3 3 d d rH d p rH p rH t 1 é I 1 < 1 1 # < 1 1 < 1 O o o o o rH CQ CQ rH CQ CQ CQ rH CQ CQ UU in UO in UU in O a in U CQ CQ Q & (a 3 t 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 d 1 i d t d rH rH rH 1 rH rH 1 rH 1 rH rH rH 1 rH rH I rH M CQ 1 rH rH rH rH rH I rH rH # rH rH rH 1 rH rH rH rH i rH rH 1 rH rH # rH rH 1 rH rH rH t rH rH 1 rH t rH rH rH rH rH S 3 S Ï i s s a u & i in kdkc3 in in rH in in rH in kd kd rH kdkdkdkd rH kdkd rH kdkd rH kdkd rH kd kd kd rH kd kd H kd rH m 1 I 1 d 1 I d I d I 1 I d 1 i d 1 t 1 1 i t 1 t 1 1 # 1 1 1 t 1 t t t 1 I 1 1 1 t t 1 CM ro rH M CM fO CQ rH CQ CM ro rH a CM ro CQ rH rH rH CM rH CM tn rH CM kd ro rH CM kd ro ro rH CM kd ro ro kd iH CM kd ro CO kd ro rH CM kd COro kd CO kd 4 k 4 k 4 k 1 4 k 4 k # 4 k # 4 k 4 k 4 k 1 4 k 4 k 1 4k 4k 4k 4k 4k 4k 1 4 k 4 k 1 4 k 4 k 4 k # 4k 4k 4k 4k 1 4 k 4 k I 4 k 4 k I 4 k 4 k 1 4 k 4 k 4 k 1 4 k 4 k t 4 k 1 rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH CM CM CM CM CM rH CM CM rH rH CM CM rH rH rH CM CM rH rH rH rH CM CM rH rH rH rH in CM CM rH rH rH rH in in i CQ CQ a O U O kf3 CQ CO CQ CQ o o u o in tn OO o O O o O O o o O o o o CQ O O o o CQ CQ O O o O CQ CQ O O O o o CQ CO OO Table IS. (continued) C(3)#8-C(2)-H(2B) 108.9 C(3)-C(4)-H(4B) 107.2 C(1)-C(2)-H(2B) 108.9 H(4A) -C(4)-H(4B) 106.9 H(2A) -C(2)-H(2B) 107.7 C(4)#8-C(5)-C(4) 102.7(19) C(4)-C(3)-C(2)#8 117.2(13) C(4)#8-C(5)-B(l) 113.2(13) C(4)-C(3)-H(3A) 108.0 C(4)-C(5)-B(l) 113.2(13) C(2)#8-C(3)-H(3A) 108.0 C(4)#8-C(5)-K(l) 125.1(10) C(4)-C(3)-H(3B) 108.0 C(4)-C(S)-K(1) 125.1(10) C(2)#8-C(3)-H(3B) 108.0 B(l)-C(5)-K(l) 74.0(7) H(3A) -C(3)-H(3B) 107.2 C(4)#8-C(5)-H(5) 109.2 C(5)-C(4)-C(3) 120.4(14) C(4)-C(5)-H(5) 109.2 C(5) -C(4) -H(4A) 107.2 B(l)-C(5)-H(5) 109.2 C(3)-C(4)-H(4A) 107.2 K(l)-C(5)-H(5) 35.2 C(5)-C(4)-H(4B) 107.2 Symmetry trômsformations used to generate equivalent atoms; #1 y+l/2,-x+l,-z+l/2 #2 -y+l,x-l/2,-z+l/2 #3 -x+3/2,-y+l/2,z #4 -y+1/2,-x+1/2,z-1/2 #5 -y + 1 /2 ,X ,Z -1 /2 #6 y , -x+1/2,z+1/2 #7 -X +1/2,y , z #8 X, -y + 1 /2 ,z 75 CHAPTERS EXPERIMENTAL 3.1. Apparatus I) Vacuum line Due to the highly air and moisture-sensitive character of many compounds, all manipulations were performed in a Pyrex high vacuum line similar to that described by Shriver.**^ The vacuum line is composed of six sections: a pumping station, a main manifold, a sub-manifold, a firactionation train, a McLeod gauge and a calibrated Toepler pump. The pumping station consisted of a Welch Duo-Seal rotary pump and a two stage mercury diffusion pump. A -196 °C (liquid N2) trap was placed between the main manifold and the diffusion pump to prevent volatiles from entering both the diffusion pump and rotary pump. A -78 °C (isopropanol/COz) trap was located between the diffusion pump and the rotary pump to keep mercury vapor from going into the rotary pump. 76 The main manifold was constructed of 25 mm diameter, 1.7 m length Pyrex tubing and equipped with five groimd glass stopcocks that connected to other sections of the vacuum line. The sub-manifold was constructed of 25 mm diameter, 0.65 m length E ^ x tubing sealed in the center and was equipped with high vacuum Kontes valves. The two halves of the sub-manifold were connected via a Kontes valve. The sub manifold had six ports: two 14/35 standard taper joints and four 9 mm solv-seal joints. A mercury blowout was attached to each port as a safety precaution in case of overpressurization. A 14/35 standard taper joint was mounted horizontally at each end of the sub-manifold to allow connection of vacuum-line extractors. The fractionation train was composed of four U-traps and a mercury manometer. At each end of this manifold was a 9 mm Solv-Seal joint with a mercury blowout. This train is used for purification or measurement of gaseous material. The McLeod gauge was positioned at the end of the vacuum line farthest firom the pumping station. The Toepler pump was made up of two heavy wall chambers (ca. 500 mL each). There is a U-trap containing crushed Pyrex glass on the inlet side of the upper chamber. This trap is cooled to -196 °C to prevent condensable gas fiom being transferred when noncondensable gas is quantified. The collected gas can be expanded into four calibrated volumes which are arranged in series and separated by a ground glass stopcock. A mercury manometer is connected to measure the collected gas. A 14/35 standard taper joint is attached in the inlet side of the Toepler pump for connection of vessels for qualitative gas analysis. The Toepler pump and the McLeod gauge was operated fiom a separate rotary pump. 77 2) Dry Box Air and moisture-sensitive compounds were also handled in either of two Vacuum Atmosphere Dry Boxes under a prepurified nitrogen environment. These boxes were filled with prepurified nitrogen, continuously circulated over Redox oxygen scavenger and Linde 3 À molecular sieves. Both boxes had analytical balances. One box was equipped with a small -40 °C refrigerator, which was used for crystallization and for storage of temperature-sensitive compounds. The dry box was entered through an ante chamber. Operation of this type of Vacuum Atmosphere Dry Box is illustrated by Shriver.^^ 3) Glassware Pyrex or Kimax round or tear drop shape flasks equipped with 9 mm or IS mm solv-seal joints were used for reaction. Adapters with a 9 mm solv-seal joint, Kontes stopcock and another 9 mm solv-seal or a standard taper 14/35 ground glass joint were employed to connect the reaction flasks to the vacuum line. A vacuum line extractor was used for filtration of air-sensitive materials. The vacuum-line extractor was connected to a horizontal port on either end of the sub-manifold. All NMR tubes and elemental analysis vials were glassblown to 9 mm solv-seal joints and flame-sealed with a torch under vacuum. Impurities of glassware were cleaned by using either a base bath (KOH/isopropanol) or aqua regia. All cleaned glassware was rinsed thoroughly with distilled water, then with acetone and dried in an oven at 175 °C prior to use. 78 4) X-ray diffraction a. single crystal Single crystal X-ray diffraction data were collected either on an Enraf-Nonius CAD4 diffractometer using graphite-monochromated Mo Ka radiation or on an Enraf- Nonius KappaCCD diffraction system with graphite-monochromated Mo Ka radiation. When the Enraf-Nonius CAD4 diffractometer was used, suitable single crystals were mounted and sealed inside glass capillaries of 0.3 or 0.5 mm diameter under N2. Unit cell parameters were obtained by a least-squares refinement of the angular settings from 25 reflections, well-distributed in reciprocal space and lying in the 26 range of 24 - 30°. The diffraction data were corrected for Lorentz and polarization effects and empirical absorption (empirically from y^-scan data). When the Enraf-Nonius Kappa CCD diffraction system was employed, the crystal was mounted on the tip of a glass fiber coated with Parabar. Unit cell parameters were obtained by indexing the peaks in the first 10 frames and refined employing the whole data set. All frames were integrated and corrected for Lorentz and polarization effects using DENZO.^ The empirical absorption correction was applied with SORTAV.’* The structures were solved by direct methods or patterson methods and refined using SHELXTL (difference electron density calculations, fiill least-squares refinements).’’ b. Powders Powder diffraction samples were graciously run by Dr. Gordon Renkes. 79 5) Nuclear Magnetic Resonance Spectra ' B NMR and NMR spectra were obtained on a Broker DPX-2S0 NMR spectrometer operating at 80 and 250 MHz, respectively. ' ^B NMR and NMR spectra were also obtained on a Broker DPX-400 NMR spectrometer operating at 128 and 400 MHz. '^B NMR and H NMR spectra were also obtained on a Broker DRX-500 NMR spectrometer operating at 160 and 500 MHz. Chemical shifts for H NMR spectra were internally referenced to proton peaks ( 6(TMS) = 0.00 ppm). Chemical shifts for "B NMR spectra were externally referenced to BFg'OEtz in CgDs (5 = 0.00 ppm). Coupling constants (J) are reported in Hertz. All NMR spectra were observed at ambient temperature except for the variable temperature experiments. 6) Inftared Spectra Inftared spectra were collected on a Mattson Polaris FT inftared spectrometer and analyzed on a Dell 433/L computer using the WinFirst software package. Samples were prepared as Nujol mulls or solutions in the dry box. Nujol mull samples were analyzed as films placed between KBr plates in an air tight sample holder. Solution samples were obtained using air tight Perkin-Elmer cells with 0.1 mm Teflon spacers between KBr or NaCl windows. Spectra were collected over 16 scans at 2 cm'^ resolution. 7) Elemental analysis Elemental analyses were performed by Galbraith Laboratories, Inc. of Knoxville, Tennesse. 80 3.2. Solvents and Reagents 1) Acetonitrile C H 3C N (Mallinckrodt) was placed in a flask with fresh P2O5, degassed and stirred for 3 to 5 days. The yellow color of the suspension indicated dryness of acetonitrile. The dry C H 3C N was then distilled into a SOO-mL pyrex storage bulb sealed by a Kontes Teflon stopcock with a 14/35 standard taper joint attached. Acetonitrile was distilled from the storage bulb immediately prior to use. 2) Ammonia NH3 (Matheson) was condensed at -78 into a pyrex storage tube containing sodium metal. The appearance of the characteristic blue color of the solvated electrons was used as an indicator of dryness of the ammonia. 3) Pyridine CsHsN (Fisher) was degassed and refluxed over sodium/benzophenone until a deep purple color formed. The dry pyridine was then distilled into a SOO-mL pyrex storage flask containing sodium/benzophenone. Pyridine was distilled fi:om the storage flask immediately prior to use. 4) Diethyl ether (C2Hs)2 0 (Baker) was degassed and stirred over sodium/benzophenone. The formation of a purple color firom the benzophenone ketyl anion indicated dryness. The dry ether was then distilled into a SOO-mL pyrex storage flask with sodium/benzophenone. Ether was distilled firom the flask immediately prior to use. 81 5) Terahydrofuran C4HgO (Mallinckrodt) was degassed and refluxed over sodium/benzophenone. The formation of a purple color indicated dryness. The dry THF was then distilled into a 500-mL pyrex storage bulb with sodium/benzophenone. THF was distilled from the storage bulb immediately prior to use. 6) Hexane CgHi 4 (Mallinckrodt) was stirred over activated 4 À molecular sieves for 5 days in a 1000-mL pyrex flask under vacuum. The dry hexane was then distilled into a SOO-mL pyrex storage flask containing Na. Hexane was distilled from the storage bulb immediately prior to use. 7) Toluene CgHsCHa (Mallinckrodt) was degassed and dried over sodium/benzophenone. The dry toluene was then distilled into a 500-mL pyrex storage flask containing sodium/benzophenone. Toluene was distilled from the storage flask immediately prior to use. 8 ) Sodium Na (chunk) was packed in a mineral oil. It was cut into small pieces, washed with hexane, vacuum-dried and stored in the dry box. 9) Borane-tetrahydrofiiran complex (1.0 M solution in THF) BH3*THF (Aldrich) was used as received and stored in the refrigerator in the dry box. 10) Mercury Hg, quadruply distilled (Bethlehem Instruments) was used as received. 82 11) Potassim hydride KH (Aldrich) was received as an oil slurry. It was washed with hexane to remove the oil and vacuum-dried. After drying, the powder was stored in the dry box. 12) 9-BBN dimer [(p-H) 2BCgHi 4]2 (Aldrich) was used as received. 13) Tris(pentafluorophenyl)borane B(C6Fs)3 (Aldrich) was used as received. 3.3. Preparation of starting materials 1) Potassium octahydrotriborate(l-) K[B3Hg] was prepared from potassium amalgam and borane-tetrahydrofUran complex (1.0 M solution in THF) by the method of Shore et al.**^ 2) Potassium (Cyclooctane-1 ,S-diyl)dihydroborate( 1 -) K[(p-H) 2BCgHi 4] was synthesized from KH and 9-BBN dimer in THF or ether by the method of Kôster and Seidel.** 3) Ammonia-solvated europium dichloride (NH3)%EuCl2 was synthesized from Eu metal and N H 4C I in liquid ammonia by the method of Howell and Pytlewski.** 4) Ammonia-solvated ytterbium dichloride (NH3)xYbCl2 was prepared from Yb metal and N H 4C I in liquid ammonia by the method of Howell and Pytlewski.*^ 83 5) Tetrahydrofüran-solvated europium dicbloride (THF)yEuCl2 was synthesized by stirring (NH3)%EuCl2 in T H F , which displaces coordinated N H 3 from the Eu^^ ion. The solvent is removed and the procedure is repeated once again to insure all the ammonia is replaced. 6) Tetrahydrofuran-solvated ytterbium dichloride (THF)yYbCl2 was synthesized by stirring in T H F , which displaces coordinated NH 3 from the Yb^^ ion. The solvent is removed and the procedure is repeated once again to insure all the ammonia is replaced. 3.4. Reactions 1) Preparation of (CH 3CN)4Yb[B3H8 ]2, 1 In a dry box a SO-mL flask containing a Teflon-coated magnetic stir bar was charged with 271 mg (1.56 mmol) of Yb metal and 164 mg (3.06 mmol) ofNH 4Cl. The flask was connected to a vacuum-line and was then evacuated. Dry NH3 (25 mL, liquid) was condensed in the flask at -78 "C and the flask was warmed to -33 °C and stirred. An immediate reaction occurred with evolution of H2 and with the formation of a golden yellow suspension. With increasing H 2 pressure, the reaction slowed appreciably. To increase the reaction rate, the solution was frozen twice at -196 °C and H 2 was removed. After 40 min, NH3 was removed, resulting in a light green NH 3-solvated solid, (NH3)xYbCl2. The flask was then charged with 240 mg (3.02 mmol) of K[B 3Hg] in a drybox and again evacuated. Next, 25 mL of dry NH 3 was condensed into the flask at - 78 and the mixture was warmed to -33 °C and stirred. The color of the suspension changed to orange-yellow. After 40 min, NH 3 was removed, resulting in a light green 84 NHs-solvated soild, (NHsXYbCk. Next, 25 mL of dry CH 3CN was condensed into the flask at -78 °C and the mixture was warmed to room temperature and stirred for 1 h. During this time, the solution turned to an orange-red color with a precipitate forming. Filtration of the reaction mixture yielded an orange-red filtrate of (CH 3CN)xYb[B3Hg ]2 and a gray precipitate. Slow removal of the CH 3CN solvent under vacuum yielded orange crystals of (CH 3CN)4Yb[B3Hg] 2. Removal of the solvent at room temperature and washing with hexane and vacuum drying gave an orange-yellow solid, gave an orange-yellow solid, (CH 3CN)o.6Yb[B3Hg] 2, whose formula was determined by elemental analysis. This orange-yellow solid was vacuum-dried again to give a yellow solid formulated as (CH3CN)ojYb[B3Hg ]2 by elemental analysis. Anal. Calcd for (CH 3CN)o.6Yb[B3Hg] 2: C, 5.17; H, 6.44; N, 3.02. Found: C, 5.17; H, 6.87; N, 3.48. Anal. Calcd for (CH 3CN)ojYb[B3Hg] 2: C, 2.71; H, 6.40; N, 1.58; B, 24.35. Found: C, 2.74; H, 6.73; N, 2.15; B, 22.25. “ B NMR (CD 3CN): S -27.7 (br s). ‘H NMR (CD3CN): Ô 0.61 (br s) 2 ) Heating of an C H 3C N solution of(CH3CN)4Yb[B3Hg]2 An C H 3C N solution of(CH3CN)4Yb[B3Hg]2, 1 was then heated at 40 “C for about 4 hours, at 60 °C for 1 h and 3 h, respectively and at 75-78 “C for 23 h and at 101 °C for 19 h 30 min. Each time the solution was cooled down to room temperature and "B NMR spectra were taken. After heating at 75-78 "C for 23 h, a decomposition product appeared. Most of the [B 3Hg]' was left in solution and the conversion to clusters was not observed. 85 3) Preparation of 4 In a drybox a SO-mL flask containing a Teflon-coated magnetic stir bar was charged with 130 mg (0.751 mmol) of Yb metal and 79,2 mg (1.48 mmol) ofNHjCl. The flask was connected to a vacuum-line extractor and was evacuated. (NH3)xYbCl2 was prepared in the same manner as described for 1 above. The flask was then charged with 115 mg (1.45 mmol) of K[B 3Hg] in a drybox and again evacuated. (NH3)xYb[B3Hg ]2 was prepared in the same manner as described for 1 above. Next, 25 mL of dry pyridine was condensed into the flask at -78 °C and the flask was warmed to room temperature and stirred for I h. During this time, the solution changed to a deep violet color with a precipitate forming. Filtration of the reaction mixture yielded a deep violet filtrate and a gray precipitate. Slow removal of the solvent under vacuum yielded violet crystals of (C5HsN)xYb[B3Hg] 2. ‘ ‘B NMR (ds-py, 233-293 K); 6-11.7 (quartet, Jbh = 96 Hz), -28.7 ppm (triplet, J bh = 31 Hz) 'H NMR (ds-py, 233-293 K): 8 3.35 (quartet, Jbh = 105 Hz), 1.79 (hr s). 4) Preparation of (THF)xYb[B 3Hg] 2, 5 In a drybox a 50-mL flask containing a Teflon-coated magnetic stir bar was charged with 130 mg (0.751 mmol) of N H 4CI. The flask was connected to a vacuum- line extractor, which was then evacuated. (NH 3)xYbCl2 was prepared in the same manner as described for 1 above. The flask containing (NH3)xYbCl2 was then charged with 115 mg (1.45 mmol) ofKEBgHg] in a dry box and again evacuated. (NH3)xYb[B3Hg ]2 was prepared in the same manner as described for 1. Next, 25 mL of THF was condensed into the flask at -78 °C and warmed to room temperature and stirred for 1 h. The solution changed to a green color with a precipitate forming. Filtration of 86 the reaction mixture yielded a green filtrate. Removal of all the solvent at room temperature, washing with hexane and vacuum-drying gave a yellow solid, (THF)ojYb[B3Hg] 2, whose formula was determined by elemental analysis. Anal. Calcd for (THF)o^Yb[B 3Hg] 2: C, 8.28: H, 6.95. Found: C, 7.88; H, 8.32. ‘ ‘B NMR: (rfa-THF, 213 K): S -30.1 (br s), -34.5 (quintet, Jbh = 79 Hz) ‘H NMR {da- THF,213K):50.19(brs) 5) Preparation of (CH 3CN)%Eu[B3Hg] 2 ,6 In a drybox a 50-mL round bottom flask containing a Teflon-coated magnetic stir bar was charged with 161.5 mg (1.063 mmol) of Eu metal and 113.4 mg (2.120 mmol) of NH4CI. The flask was connected to a vacuum-line, which was then evacuated. Dry NH3 (25 mL, liquid) was condensed in the flask at -78 °C and the flask was warmed to - 33 °C and stirred. An immediate reaction occurred with evolution of H 2 and with formation of a yellow-green suspension. To increase the reaction rate, the solution was fi:ozen twice at -196 “C and H 2 was removed. After 40 min, the NH 3 was removed resulting in a pale grey-green NH 3-solvated solid, (NH 3)%EuCl2. The flask was then charged with 163.5 mg (2.054 mmol) of K[B 3Hg] in a dry box and again evacuated. Next, 25 mL of dry NH 3 was condensed into the flask at -78 °C and the mixture was warmed to -33 °C and stirred. The color of the suspension changed to bright yellow- green. After 40 min, the NH 3 was removed, resulting in a light yellow-green solid. Next, 25 mL of dry CH 3CN was condensed into the flask at -78 °C and the mixture was warmed to room temperature and stirred for I h. During this time, the solution turned bright yellow-green with a precipitate forming. Filtration of the reaction mixture yielded a brilliant yellow-green filtrate. Removal of the solvent at room temperature, washing 87 with hexane and vacuum-drying gave a pale green solid, (CHjChOo.iEulBjHg]:, whose formula was determined by elemental analysis. Anal. Calcd for (CHsClSOo.iEuPsHglz: C, 1.01; H, 6.93; N, 0.59; B, 27.36. Found: C, 0.61; H, 8.96; N, 0.51; B, 33.02. 6) Preparation of (THF) 4Yb[(p-H) 2BCgHi 4]2 ,8 In a dry box, 134 mg (3.34 mmol) of K H and 305.2 mg (1.251 mmol) of 9-BBN dimer were placed in a 50-mL flask containing a Teflon-coated magnetic stir bar. The flask was connected to a vacuum extractor and another 50-mL flask in a dry box. It was then connected to a vacuum line and was evacuated. Next, 25 mL of dry THF was condensed into the flask at -78 °C and the mixture was warmed to room temperature and stirred overnight. Then it was filtered to give a colorless filtrate of K [B C gH i 6] and excess K H on the frit. The next day, in a dry box, a 50-mL flask containing a Teflon- coated magnetic stir bar was charged with 223 mg (1.29 mmol) of Y b metal and 135 mg (2.52 mmol) of NH4CI. (NH3)%YbCl2 was synthesized in a procedure identical to that described above for 1. (THF)yYbCl2 was prepared by stirring the ammonia-solvated complex in THF. The solvent was pumped off and the procedure was repeated twice again to insure all the ammonia was replaced. The flask was brought into the dry box and the T H F solution of Kj^BCgHta] was added dropwise by pipette to the (THF)yVbCl2. The color of solution changed to orangish brown with a precipitate forming. Filtration of the reaction mixture yielded an orangish yellow-brown filtrate of 8 . Cooling this filtrate to 0 °C with slow removal of the THF solvent under vacuum yielded yellow X-ray quality crystals of 8 . Removal of the solvent at room temperature, washing with hexane 88 and vacuum-drying gave a yellow solid formulated as Yb[BCgHi 6]2 by elemental analysis. Anal. Calculated for Yb[BCgHi 6]2: C, 45.86; H, 7.70. Found: C, 44.20; H, 9.34. "B NMR spectrum (d-THF): -12.4 ppm (triplet, Jbh = 66 Hz). 7) The reaction of (THF) 4Yb[(p-H) 2BCgHM ]2 with B(C6F;)3 In a dry box, a 50-mL flask containing a Teflon-coated magnetic stir bar was charged with 136 mg (3.39 mmol) of KH and 309 mg (1.27 mmol) of 9-BBN dimer. A THF solution ofK[BCgH|g] was prepared as in the procedure described for 8. (THF)yYbCl2 was synthesized from 221 mg (1.27 mmol) of Y b and 136 mg (2.54 mmol) of NH4CI according to the procedure described for 8 . A THF solution of8 was prepared as stated in the procedure described for 8 . The flask was brought into the dry box and 638 mg (1.25 mmol) of B(C 6Fs)3 was added. B(CgF 5)3 dissolved completely in the THF solution. The flask was connected to a vacuum-line and the solution was frozen at -196 °C and the N 2 was removed. The color of the solution changed to yellow. Then the flask was warmed to room temperature and stirred for 3 hr. "B NMR spectrum of the reaction solution was taken. ^*B NMR (THF): 6 -9.6 (t, Jbh = 68 Hz), -25.4 (d, Jbh = 91 Hz). 8) Preparation of [(THF)4K]2{Eu[(p-H)2BCgHu]4}, 10 In a dry box, 136.9 mg (3.413 mmol) of ICH and 306.9 mg (1.258 mmol) of 9- BBN dimer were placed in a 50-mL flask containing a Teflon-coated magnetic stir bar. The flask was connected to a vacuum extractor and another 50-mL flask in a dry box. It was then connected to a vacuum line and was evacuated. Next, 25 mL of dry THF was condensed into the flask at -78 °C and the mixture was warmed to room temperature and 89 stirred overnight. Then the solution was filtered to give a colorless filtrate of K[BCgHi 6] and excess KH on the fiit. The next day, in a dry box, a SO-mL flask containing a Teflon-coated magnetic stir bar was charged with 202 mg (1.33 mmol) of Eu metal and 140 mg (2.61 mmol) of NH 4CI. (NH3)%EuCl2 was synthesized in a procedure identical to that described for 6 above. (THF)yEuCl2 was prepared by stirring the ammonia-solvated complex in THF. The solvent was pumped off and the procedure was repeated twice to insure all the ammonia was replaced. In the dry box, the solution of K[BCgHi 6] was added dropwise by pipette to the (THF)yEuCl 2. The color of the solution changed to a bright yellow-green solution with a precipitate forming. Filtration of the reaction mixture yielded a bright yellow-green solution. Cooling this filtrate to 0 °C with slow removal of the THF solvent under vacuum yielded pale bright yellow X-ray quality crystals of 10. 90 CHAPTER 4 INTRODUCTION 1. Cyanide-bridged lanthanide-transition metal complexes Due to the restricted radial extension of the 4f valence orbitals, few compounds with direct lanthanide-transition metal bonds have been structurally characterized.^'^'’’ Thus complexes in which the lanthanide and the transition metal are bonded through bridging ligands such as hydrogen, carbonyl, cyanide, etc., comprise the largest group among structurally characterized lanthanide-transition metal complexes. The cyanide ion has been used to bridge lanthanides and transition metals in the heterometallic complexes. The nitrogen atom of the cyanide ligand is connected to the lanthanide while the carbon atom of the cyanide ligand is bonded to the transition metal. Interesting magnetic and semi-permeable membrane properties of the complexes containing lanthanides and Fe(III) and Co(III) ions have led to syntheses of a series of hexacyano complexes, LnM(CN) 6»nH2 0 (M = Fe, Co; n = 4 or 5)****^* in which the lanthanides and transition metals are connected through cyanide bridges. Hulliger et al. performed X-ray powder diffraction studies to show that the pentahydrates crystallized in 91 the hexagonal space group while the tetrahydrates crystallized in the orthorhombic space group (fig. 29).^’ The lanthanides have an eight-coordinated square antiprismatic geometry in the tetrahydrates, e.g. SmN 6(H20)2 group in SmM(CN)6*4H20 and a nine- coordinated tricapped trigonal prismatic geometry in the pentahydrates, e.g. LaNg(H 20)3 group in LaM(CN)6*SH20. Transition metals have octahedral arrangements in both the tetrahydrates and the pentahydrates. Two uncoordinated water molecules occupy holes inside the structures of the tetrahydrates and the pentahydrates. Mullica et al. also synthesized a series of the double salt ferrocyanides, LnKFe(CN)6*xH20 (Ln = La, Ce, Pr, Nd, Sm, Yb and x = 4,4,4,4,3,3.5, respectively).^^ These complexes were particularly interesting because of their semi- permeable membrane properties. X-ray analyses showed that the double salt ferrocyanides containing the lanthanides were isomorphous (Ln = La, Ce, Pr, Nd) or similar (Ln = Sm, Yb) to that of LaFe(CN)6*5H20. The only difference is that some of the uncoordinated water molecules in the cage-like cavities inside the structures of the hexacyano pentahydrates are replaced by potassium ions in the structures of the double salt ferrocyanides (fig. 30). Tetracyanopalladate(II) structures containing lanthanide cations (Ln = Nd, Eu) have been reported.**’ ** However, no structural details were given. A series of rare earth compounds, Ln 2[Pt(CN)4]3*xH 2 0 ,*’ (x = 18,21) have also been reported. Spectroscopic evidence and preliminary X-ray data indicate that these complexes choose a quasi-one-dimensional structure common to the tetracyanoplatinates(II). Shore et al. synthesized a series of nonaqueous one-dimensional cyanide-bridged lanthanide(ni)- transition metal complexes as potential precursors to heterogeneous catalytic reactions.*^’ 92 d (a) (b) Figure 29. (a) View of the hexagonal LaPe(CN) 6*5H2 0 structure and (b) projection of the orthorhombic SmFe(CN) 6»4H2 0 . Figure 30. Stereoview of FefCNje^ octahedra arrangement of LaKFe(CN) 6»4H2 0 . 93 69,70 Yyig will be discussed in the next section of this chapter. Knoeppel and Shore also reported the crystal structures of {(DMF)4EuLn(CN)4}«7 * (Ln = Ni, Pt), in which each tetracyanometalate(Q) anion links three europium atoms to form a one-dimensional ladder (fig. 31). 2. Classification of non-aqueous cyanide-bridged lanthanide(in)-transition metal complexes The synergic interaction between the lanthanide and the transition metal of cyanide-bridged lanthanide-transition metal complexes has been exhibited through the capability of these compounds to work as precursors in heterogeneous catalytic reactions. For example, Shore and Ozkan, et al. recently reported that the bimetallic Yb-Pd catalyst prepared from the precursor, {(DMF)ioYb 2[Pd(GN) 4]3}«, on a titania surface showed better performance over the Pd-only catalyst in the reduction of NO by CH 4 in the presence ofOz.^ The reactions of LnCb with Kz[Pd(CN) 4] in a 2 to 3 molar ratio produced three different, but related types of one-dimensional polymeric arrays and these arrays are classified as A, B, and C structural types.*®’®’™ The one-dimensional arrays having the general formula, {(DMF)ioLn 2[M(CN)4]3}«, (Ln = Y, Sm, Eu, Er, Yb ; M = Ni, Pd, Pt) have been prepared by the reaction of LnCls with Kz[M(CN)4] in a 2 to 3 molar ratio in DMF (DMF = N, N'-dimethylfonnamide) (eqn. 7) and the crystal structures have been categorized as structural type A and type B. 94 Figure 31. Molecular structure of a portion of the one-dimensional “ladder” in {(DMF)4Eu[Ni(CN)4]}«. 95 2 LnCIa + 3 K2[Pd(CN)4l SME— ^ {(DMF)ioLn2[M(CN)4]3}. + 6KCI (7) Type A [Ln = Sm, Eu, Er, Yb, M = Ni] TypeB [Ln = Y, Sm, Eu, Yb, M = Pd; Ln = Yb, M = R] Both type A and type B complexes crystallize in the triclinic space group, PT. They both have the same asymmetric unit, {[M(CN) 2]Ln(DMF)s[M(CN)4]} (I in Scheme I) and the same repeating unit, {[M(CN) 4](DMF)5Ln[M(Q4)4]Ln(DMF)5[M(CN)4]} (H in Scheme 1). The difference between type A and type B structures derives from the way in which the repeating units combine to generate the arrays (Scheme 1). Their crystal shapes are also different. Type A crystals are thin plates, while type B crystals are rhombuses. The complexes, {(DMF)ioLn 2[Ni(CN)4]3}ao, (Ln = Sm, Eu, Er, Yb, M = Ni) are considered to have type A structures in which the repeating unit is translated along the ac diagonals of the lattice to generate a single strand one-dimensional array. These complexes are isomorphous. The crystal structure of {(DMF)ioEr 2[Ni(CN)4]3}« is shown in figure 32a. Two cis-bridging [Ni(CN) 4]^‘ anions bridge two Er(III) ions to give a "diamond"-shaped ErzNiz metal core. These "diamond"-shaped ErzNiz metal cores are then connected together by trans-bridging cyanide ligands of [Ni(CN) 4]^' anions. The crystal structures of {(DMF)ioLnz[Pd(CN)4]3}*, (Ln = Y, Sm, Eu, Y b, M = Pd; Ln = Y b , M = Pt) are classified as type B structures. Unlike type A structures, the repeating unit is translated along the crystallographic a axis of the lattice in type B structures. These complexes are isomorphous. The crystal structure of {(DMF)ioYbz[Pd(CN)4]3}ao is displayed in figure 3 2 b . The crystal structure consists of 96 V V S * * V L .A X ■ ^AqmmetricaRit OQScpcatiaguit .c* “«il e» S 4, _ V " * > TO m. i "'Y \ j f A y s y > e?* 8 8 *' ^oÆ oi-u'^ 4, A y * /^=N TO)*yp#A \ (IV) Scheme 1. The ways in which repeating units combine to generate two different but related structural type A and B 97 two inverted parallel zigzag chains. These zigzag chains are formed by cis-bridging [Pd(CN) 4]~' anions. The two chains are then linked through the Yb{III) ions by trans bridging [Pd(CN) 4]^' anions to give a double-strand one-dimensional array. In both type A and type B structures, each Ln(III) ion has a slightly distorted square antiprismatic coordination geometry (fig. 33a and fig. 33b). Each Ln(III) ion is coordinated to five oxygen atoms from the DMF ligands and three nitrogen atoms from the bridging cyanide groups of [M(CN) 4]^' anions. Two of three coordinated nitrogen atoms share an edge of one of the bases of the square antiprism, while the third nitrogen atom resides on a comer of the other base opposite to the shared edge. In the type A structure, the edge-sharing nitrogen atoms are from cyanide ligands of two cis-bridging [Ni(CN)4]^‘ anions, while the third nitrogen atom comes from a cyanide ligand of a trans bridging [Ni(CN) 4]^' anion. In the type B structure, one of the edge-sharing nitrogen atoms and the third nitrogen atom are from cyanide ligands of two cis-bridging [M(CN)4]^' anions. The other edge-sharing nitrogen atom comes from a cyanide ligand of a trans-bridging [M(CN) 4]^' anion. In both type A and type B complexes, the coordination geometry around M (M = Ni, Pd, Pt) is approximately square planar. The widest C-M-C bond angles in type A and type B complexes are the ones that bridge to two sterically crowded Ln(III) ions in a cis-fashion. Even though C-M-C bond angles show variations, M-C-N bonds are generally linear. In contrast, Ln-N-C bond angles show changes probably due to the sterically crowded environment around the Ln(IH) ions. The M-C and CN bond lengths also vary according to the bonding modes of the cyanide group but do not show much variation. 98 (a) (b) Figure 32. Molecular structures of a portion of the one-dimensional arrays: (a) {(DMF),oEr2[Ni(CN)4]3}-and(b) {(DMF),oYb 2[Pd(CN) 4]3}«. (a) (b) Figure 33. Coordination geometry around the lanthanide ions in (a) {(DMF)ioEr2[Ni(CN)4]3}«and(b) {(DMF)ioYb2[Pd(CN) 4]3}«. 99 It was shown that {(DMF)ioLn 2[Ni(CN)4]}« can crystallize as either type A or type B structures. The crystals with structural type A convert to structural type B, when they are left in the mother liquor for an extended period of time (ca. 10 days) (fig. 34). When the crystals with structural type B are dissolved in DMF, they crystallize initially in type A form, however, they convert to type B structure on standing for an extended period of time. These observations suggest that the type A structure is the kinetically favored form, while the type B structure is the thermodynamically favored form. The transition metals of [M(CN)4]^' anions seem to determine the structural types. The compounds of the lanthanides and Ni^^ give type A crystals that can he converted to type B crystals, while the compounds of the lanthanides and Pd^^ or Ft^^ only produce type B crystals (scheme 2). I^Naafhi l * N o a |h t rhDMr a s / Y “ > nni«w|fci Type A TypeB Figure 34. The conversion of Sm-Ni Scheme 2. Different crystallization pattern complex fix)m structural type A to type B. of Ln-Ni complex and Ln-Pd complex. 100 The solid state infiared spectra of complexes which belong to type A and type B structures show clearly different patterns suggesting the presence of different structural types (fig. 35). The Nujol mull infrared spectra of type A complexes show bands that have higher vcN stretching frequencies than the normal band of K 2[Ni(CN)4] (2127 cm These bands are assigned to the stretching modes of the bridging cyanides because bridging cyanides absorptions generally appear at higher frequencies than terminal cyanides. The remaining cyanide absorption bands are assigied to terminal cyanides because they show up in the nonbridging cyanide stretching region ofKz[Ni(CN) 4] (2127 cm '). In the solid state infrared spectra of type B complexes, the bands that appear at higher frequencies than those of K 2[Pd(CN) 4]*H 2 0 (2134 cm*')’^ or K 2[Pt(CN)4]* 3H20 (2134 cm ')^^ are attributed to bridging cyanides. The absorptions around the frequencies of the normal modes of K 2(Pd(CN) 4]*H 2 0 or K2[Pt(CN)4]* 3H2 0 are assigned to the stretching modes of the terminal cyanides. As a note, the solid state infrared spectra of type B complexes with [Pd(CN) 4]^' are similar to those with [Pt(CN) 4]^’- The solution infrared spectra of type A and type B complexes in DMF are different from their solid state Nujol mull infrared spectra, indicating that the species in solution are dissimilar to those in the solid state (fig. 36). The presence of some higher absorption bands except the ones of [Ni((ZN) 4]^', [Pd(CN) 4]^* or [Pt(CN) 4]^' in the DMF solution infrared spectra suggests that partial ionization might occur to give ion-paired complexes with bridging cyanides. If complete ionization occurred, only one stretching band of the [M(CN) 4]^' (M = Ni, Pd, Pt) would appear. Earlier conductivity studies also supported partial ionization which would occur through partial collapse of the cyanide bridges between the lanthanide and the transition metal, hiterestingly, when the 101 ((DMF)nSm ,[M (CN)4|i)i {(DM F)„Eu,lPd(CN)4hl. lypaA ((DMF),.Smi[Ni(CN)4|i)<. {(D M F),.Y h,|Pd(CN )4|.l, ((DMF),, Er,[NKCN).|.), {(DMF)„yb,[NKCN).Iil, ((D M F)„V b,|PI(CN )4l.l, I I 21H aw WimwWr (Vgi.air') W k m m w M r (■) 0» Figure 35. Solid-state infrared spectra of (a) type A complexes and (b) type B complexes. IV paB ((DMF),.Sm,|Pd(CN)4|,), {(DMF)»Eui(Pd(CN)4|i). ((DMF)i.SmilNKCN)4|i|. TyptA ((D M F),.Y b,[Pd(CN )4l,l, ( ( D M F ) „Er.[Ni(CN).|.U ^ y r ~ ^ ((D M F)„Y b,(Pl(CN )4|,), ( ( D M F ) „ Y b 22S0 2 i n 2 1 » » N M O rtWbi.wM WmmmMt (vai.enr') (•) Figure 36. Solution infrared spectra of (a) type A complexes and (b) type B complexes. 102 complexes of both type A and type B having the formula, {(DMF)ioLn 2[Ni(CN)4]3}ooi (Ln = Sm, Eu) are dissloved in DMF, they give indistinguishable solution infrared spectra of structural type A. This agrees with the fact that crystals of both type A and type B crystallize initially in structural type A form. When the fairly large lanthanide CeCb was used under similar reaction conditions to those of type A and B complexes, zigzag chain one-dimensional arrays with cyanide- bridged "diamond"-shaped CezMz metal cores having formula, {(DMF)i2Ce2[M(CN)4]3}«. (M = Ni, Pd) were produced. These complexes were prepared according to eqn. 8.1 and 8 .2 , respectively. 2CeCl3 + 3NiCl2 + 12KCN- — {(OMFlizCealNKCNlJa). + 12KCI (8.1) 2CeCl3 + 3K2lPd(CN)4l — {(DMF)i2Ce2(Pd(CN)4]3}. + 6KCI (8.2) These complexes are classified as structural type C. The cyanide-bridged "diamond"- shaped Ce 2M2 metal cores, which are similar to those observed in structural type A, are formed by two cis-bridging [M(CN) 4]^' (M= Ni, Pd) anions. These "diamond' -shaped Ce2M2 metal cores are then connected through Ce(UI) ions by trans-bridging cyanide ligands of [M(CN) 4]^' anions to give a zigzag chain one-dimensional array, unlike the straight chain one-dimensional array of structural type A (fig. 37). In addition to the zigzag direction of the chain, another significant difference between type A and type C structures is that each Ce(III) ion has a nine-coordinate mono capped square antiprismatic coordination geometry instead of a square antiprism (fig. 38). The Ce(m) atom is coordinated to six oxygen atoms from the DMF ligands and three nitrogen atoms from bridging cyanide ligands of |M(CN) 4]^' anions. Two of three coordinated nitrogen atoms occupy one comer of each base of the square antiprism 103 N " N12 NM 'C12 fil, j ^ N 22 Figure 37. Molecular structure of {(DMF)i2Ce2[Ni(CN)4]3}o oa CM CM MM C l* « % CM< IM* CM cw CM CM Figure 38. Coordination geometry around the Ce(III) ion in {(DMF)i 2Ce2[Ni(CN)4]3}. 104 respectively, and share one edge of the antiprism with the third nitrogen atom. The remaining vertices of the square antiprism are occupied by five oxygen atoms firom the DMF ligands. One of the edge-sharing nitrogen atoms is from a trans-bridging cyanide ligand of a [M(CN) 4]^‘ anion. The other nitrogen atoms come from two cis-bridging cyanide ligands of two [M(CN) 4]^' anions. The base, which has two edge-sharing nitrogen atoms, is capped by one oxygen atom from the DMF ligand to generate a mono capped square antiprismatic coordination geometry around the Ce(lII) ion. The coordination geometry around the nickel or palladium atoms is almost square planar like type A and B structures. The widest C-M-C angles in type C structures are the ones which bridge two Ce(III) ions in a cis-fashion. The solid state infmred spectra of type C complexes show different patterns to those of type A or B complexes, suggesting the presence of a different structural type (fig. 39a). The solid state Nujol mull infrared spectra of C complexes show bands at higher stretching frequencies than the normal stretching mode of K 2[Pd(CN) 4] (2134 cm '). These bands are assigned to the stretching mode) of the bridging cyanides because the absorption bands of the bridging cyanides usually appear at higher frequencies than those of the terminal cyanides. The remaining cyanide stretching bands are assigned to the terminal cyanides because they appear in the nonbridging cyanide stretching region ofKz[Pd(CN) 4] (2134 cm*'). The solution infrared spectra of type C complexes are different from their solid state infrared spectra suggesting that different species exist in the solid state and solution. Interestingly, the solution infrared spectra of type C complexes show different patterns according to the transition metals of [M(CN) 4]^‘ anions (fig- 39b). One complex, which 105 contains [Ni(CN)4]^', shows a pattern similar to that of structural type A. The other complex with [Pd(CN) 4]^’ displays a pattern parallel to that of structural type B. The presence of higher stretching bands than the normal vibrational modes of [Ni(CN) 4]^' or [Pd(CN) 4l^' in the DMF solution infrared spectra suggests that partial ionization might occur to produce some ion-paired complexes with bridging cyanides. 2250 2200 2150 2100 2050 2250 2200 2150 2100 2050 WiveuDben(cii‘‘) W:vmumkn(cm') (a) (b) Figure 39. (a) Solid-state infrared spectra and (b) solution infrared spectra of type C complexes. 106 Under similar reaction conditions to the preparation of type A and type B complexes, a I to 1 molar ratio of SmCh and Kz[Ni(CN) 4] in DMF or YbCb and K2[Ni(CN)4] in DMA yielded the one-dimensional arrays, {(DMF);Sm[Ni(CN) 4]Cl}« and {(DMA) 4Yb[Ni(CN)4]Cl}«, (DMA = N, N’-dimethylacetamide) (eqn. 9.1 and eqn. 9.2).’* SmClj + K2lNi(CN)4l -----^ -----► ((DMF)5SmlNi(CN)4lCI}, + 2KCI (9.1) YbCIa + K2[Ni(CN)4] “ ââ ► {(DMA)4Yb[NI(CN)4]CI}. + 2 KCI (9.2) These complexes are not good potential precursors to bimetallic catalysts because they contain chloride ion, which is a poison in heterogeneous catalytic reactions. Unlike type A, B, and C, these complexes crystallize in the monoclinic space group, P2|/n. The inversion operation on Ni atoms of the asymmetric unit, {(DMF)sSm[Ni(CN) 2]2Cl} gives the repeating unit {(DMF)sSm[Ni(CN) 4]2Cl), which translates along the crystallographic c axis of the lattice to generate a zigzag single-strand chain (fîg. 40a and 40b). The Sm(in) ion has a slightly distorted square antiprismatic coordination geometry (fig. 41a). In addition to one chloride ion, the Sm(III) ion is coordinated to five oxygen atoms from DMF ligands and two nitrogen atoms firom the bridging cyanide ligands of the [Ni(CN) 4]^* anions. Two nitrogen atoms occupy one comer of each base respectively and share one edge of the antiprism with the chloride ion. The five oxygen atoms are located on the remaining vertices. Meanwhile, the Yb(III) has a seven- coordinate pentagonal bipyramidal coordination geometry in the complex, {(DMA)4Yb[Ni(CN)4]Cl}«, (fig. 41b). This is likely due to the smaller ionic radius of Yb(ni) compared to that of Sm(III) and the larger ligand size of DMA versus DMF. The 107 N13? 01 (a) (b) Figure 40. Molecular structures of a portion of the one-dimensional arrays; (a) {(DMF)5Sm[Ni(CN)4]Cl}«and(b) {(DMA)4Yb[Ni(CN)4]CI}«. (a) (b) Figure 41. Coordination geometry around the lanthanide ions in (a) {(DMF)5Sm[Ni(CN)4]Cl}coand(b) {(DMA) 4Yb[Ni(CN)4]Cl}_. 108 equatorial vertices are occupied by two nitrogen atoms fiom the bridging cyanide ligands of the [Ni(CN) 4]^' anions and three oxygen atoms from DMA ligands. The chloride ion and the remaining oxygen atom from the DMA ligand are positioned on axial vertices trans to each other. The coordination geometry around the Ni atoms is approximately square planar. One of the Yb-N-C bond angles shows a slight deviation from linearity (162.5(7)“) probably due to the sterically crowded environment around the Yb(in) ion. The Ni-C and CN bond lengths in these complexes are normal. The solid state Nujol mull infrared spectra of these complexes show different patterns to those of type A, B or C complexes, indicating the presence of a different structural type (fig. 42a). The absorption bands, which have higher stretching frequencies than the normal vibrational mode of K 2[Pd(CN) 4] (2134 cm '), are assigned to those of the bridging cyanides. The remaining cyanide stretching bands are attributed to a terminal cyanide vibrational mode. The DMF or DMA solution infrared spectra of these complexes are different from their solid state infrared spectra, indicating the existence of distinct species in solution and the solid state. Interestingly, the solution infrared spectrum of {(DMF)sSm[Ni(CN)4]Cl}oo in DMF is almost identical to those of type A complexes. Meanwhile, the solution infrared spectrum of {(DMA) 4Yb[Ni(CN)4]Cl}« in DMA shows almost complete ionization displaying a very weak band in the bridging cyanide stretching region (2146 cm*') and a very strong band in the terminal cyanide stretching region (2112 cm*') (fig. 42b). 109 {(DMF)iSmpri(CN).lCI}» {(DMF)iSm{NKCN)*lCI}. {(DMA).Yb[Ni(CN).|CI)- {(DMA).Yb{\i(CN)4lClJ» 2100 2100 2060 2200 2100 2000 (•'«.or'» (■) Figure 42. (a) Solid-state infrared spectra and (b) solution in 6 ared spectra of complexes {(DMF)sSm[Ni(CN)4]Cl}« and {(DMA)4Yb[Ni(CN)4]Cl}«. 110 statement of Problems The goal of this research is to prepare cyanide-bridged lanthanide(III)-pailadium complexes and to characterize these complexes with single crystal X-ray diffraction and IR spectroscopy. These complexes are potential precursors to heterogeneous bimetallic catalysts. Coprecipitation, ion-exchange or coimpregnation of metal salts containing desired metals onto the support, followed by calcinations and then high temperature reduction are typically used to prepare bimetallic particles supported on oxide surfaces.^'*’ However, when this methodology is used, it is difficult to control stoichiometries and the size of the bimetallic particles. Previous studies have demonstrated that heteropolynuclear clusters containing direct metal-metal bonds supported on a magnesia support can be thermally decomposed to give very small bimetallic particles with the same composition as that in the precursor.^^ Shore et al. have synthesized a series of nonaqueous one-dimensional cyanide- bridged lanthanide-transition metal complexes as potential precursors to heterogeneous catalytic reactions.^'* “ These complexes show three different types of polymeric arrays classified as A, B and C structural types. Even though cyanide-bridged lanthanide-palladium complexes do not have direct bonding between the two metals, the lanthanide and palladium can be brought into intimate contact during the thermal decomposition process. It was reported that a bimetallic Yb-Pd catalyst prepared from a 111 cyanide-bridged lanthanide-palladium complex showed better performance over the Pd- only catalyst in the reduction of NO by CH 4 in the presence of Tetracyanopalladate, [Pd(CN) 4]^'> was chosen because of its ability to form stable complexes with the lanthanides through bridging cyanide. Dimethylformamide (DMF) was chosen to occupy the empty coordination sites of the lanthanide ions after bonding to [Pd(CN) 4]^' because it is sufficiently polar to dissolve LnCb and K2[Pd(CN) 4] and it can be easily removed without contamination of the bimetallic catalysts upon thermal decomposition. Especially La(III) and Gd(III) are chosen as the lanthanide ions because of their high electropositive character, which is believed to help inhibit oxidation of palladium in the heterogeneous catalytic reaction. 112 CHAPTERS RESULTS AND DISCUSSION I. Synthesis and infrared spectral studies of {(DMF),oGd 2[Pd(CN)j 3}., 11 The one-dimensional array, {(DMF),oGd 2[Pd(CN)J]}., 11 was obtained quantitatively via the metathesis reaction between GdCl, and K 2[Pd(CN)J'H 2 0 with a 2 to 3.2 molar ratio in DMF at room temperature (eqn. 10). 2GdCl3 + 3K2[Pd(CN)4]H20— -■» {(DMF),oGd 2[Pd(CN) 4]3}. + 6 KCI + SHgO (10) K2[Pd(CN) 4]*H 2 0 was used as the starting material rather than KilTdfCN)^ to avoid the decomposition that occurs during the drying process of K 2[Pd(CN) 4]* 3 H2 0 .^^ K2[Pd(CN) 4]*H 2 0 was prepared by drying of K 2(Pd(CN) 4]»3 H2 0 under dynamic vacuum at 100°C for several hours.^* The reaction mixture was stirred for IS days to ensure complete removal of chloride as KCl. The low solubility of GdCl, also contributed to the long reaction time. Within 24 hours, colorless X-ray quality chunlty crystals of {(DMF),oGd 2[Pd(CN) 4]j}, were grown ftom the viscous oil that formed after removal of the DMF under dynamic vacuum. Elemental analysis of the solid, which was obtained 6 om drying the crystals under dynamic vacuum for 12 to 14 hours at room temperature, 113 showed the loss of one DMF molecule per empirical unit. The infiaied spectra of 11 in the solid state (Nujol mull) and in DMF solution are consistent with those of structural type B of cyanide bridged lanthanide(III) transition metal com plexes.^T he solid state Nujol mull infrared spectrum for 11 shows three CN stretching bands (Fig. 43a). The two cyanide stretching bands of Ki[Pd(CN)4]H20,2159 cm ‘ and 2147 cm * shift to slightly higher frequencies, 2173 cm * and 2160 cm *. These two stretching bands are assigned to the stretching modes of the bridging cyanides because their absorption bands generally appear at higher frequencies than those of the terminal cyanides." The stretching band at 2135 cm * is assigned to the stretching mode of the nonbridging cyanide ligand in the complex because it shows up in the terminal cyanide stretching region ofK 2[Pd(CN)J (2134 cm')." The DMF solution infrared spectrum of 11 shows four stretches (Fig. 43b). The solution infrared spectrum of 11 is different from its solid state infrared spectrum, which suggests that the species in solution are uot the same as in the solid state. If complete ionization occurred, only one stretching band of[Pd(CN)J\ 2125 cm ', would appear. The stretching band at 2125 cm * of 11 is thus assigned to the terminal cyanides. The presence of the three other higher stretching bands at 2163 cm'*, 2142 cm * and 2135 cm '*, indicates that partial ionization might occur to give some ion-paired complexes containing bridging cyanides such as (CN)^d(p-CN)yGd(DMF)^. 2. Molecular structure of {(DMF),oGd2|Pd(CN) 4]3}^ 11 The crystal structure of 11 was solved by Dr. Jianping Liu. Crystallographic data for 11 are listed in Table 16 and atomic coordinates are given in Table 17. Selected 114 1 M W milimM (a) I I m 2200 2150 2100 2050 Wmumkm(cm') (b) Figure 43. (a) Solid-state infiared spectrum and (b) solution infirared spectrum of {(DMF)„Gdj[Pd(CN)4]3}..ll. 115 bond lengths and angles are reported in Table 18. 11 belongs to the type B class of structures among the three types of structures of one-dimensional array cyanide bridged lanthanide(in)-transition metal complexes."^ The structure of 11 is isomorphous with the structures of {(DMF),oLn2[M(CN)4]3}„ (Ln = Sm, Eu, Yb, M = Pd ; Ln = Yb, M = Ft) 66.67 yyg crystal structure of1 1 consists of double strand one-dimensional arrays that crystallize in the triclinic space group. Pi (Fig. 44). 11 has the asynunetric unit {[Pd(CN) 2]Gd(DMF)j[Pd(CN) 4]}. The asymmetric unit generates the repeating unit {[Pd(CN) 4](DMF)5Gd[Pd(CN) 4]Gd(DMF)s[Pd(CN) 4]} by an inversion operation on Pd in [Pd(CN)j. The repeating unit is translated along the crystallographic a axis of the lattice. Two cyanide ligands of the [Pd(CN) 4]^ anions bridge the Gd(III) ions in a cis- fashion to give two inverted parallel zigzag chains. The two chains are then linked through the Gd(IIl) ions by trans-bridging [Pd(CN) 4]^' anions to give a double-strand one dimensional array. The coordination geometry around each Gd(m) ion is a slightly distorted square antiprism (fig. 45). Each Gd(III) ion is bound to five oxygen atoms from the DMF ligands and three nitrogen atoms fi*om the bridging cyanide ligands of the [Pd(CN) 4]^' anions. Two of the three coordinated nitrogen atoms share an edge of one of the square bases, while the third nitrogen atom occupies the vertex of the other square base opposite to the nitrogen-nitrogen shared edge. The five oxygen atoms &om the DMF ligands reside on the remaining vertices of the square antiprism. One (N11) of the edge-sharing nitrogen atoms and the third nitrogen atom (NI2A) are fiom the two cyanide ligands of two cis-bridging pdfCN)^]^ anions. The other (N21) of the edge- sharing nitrogen atoms comes firom a cyanide ligand of a trans-bridging [Pd(CN) 4]^* anion. 116 Figure 44. Molecular structure of {(DMF),oGd2[Pd(CN) 4]3}oo, 11. 117 CSA Figure 45. Square antiprismatic geometry around the Gd(III) ion in {(DMF),oGdj[Pd(CN)4L}«,ll. 118 The average Gd-0 bond length is 2.361(5) Â, while the average Gd-N bond length is 2.505(0) A for 1 1 . The coordination geometry around the Pd(II) ion is approximately square planar. The C-Pd-C bond angle ranges from 87.7(2)“ to 92.4(2)“ for 11. The widest C-Pd-C bond angle is the C(11)-Pd(l)-C(12) angle that bridges two sterically crowded Gd(III) ions in a cis-fashion. However, the sterically crowded environment around the Gd(III) ion does not significantly affect the Pd-C-N angles ranging from 175.2(4)“ to 178.5(4)“. Contrary to this, the linearity of the Gd-N C bond angles is infiuenced ranging from 152.0(3)“ to 174.1(4)“. The average Pd-C and CN bond lengths are 1.992(2) A and 1.146(8) A, respectively and show variations concerning terminal and bridging modes, yet are thought normal. The crystal structure of 11 shows one type of rotationally disordered DMF ligand.^ Rotational disorder around the Gd-0 axis is observed for the DMF molecules designated as 04 and 05 (fig. 46a). The other type of rotational disorder of DMF molecules around the Ln-O-N axis was not observed (fig. 46b).‘^ The occupancies for the disordered carbon and nitrogen atoms were determined as 0.5. Disordered carbon and nitrogen atoms were refined isotropically. 119 (a) (b) Figure 46. Possible rotational disorder of the DMF ligands (a) around the Ln-0 axis and (b) around the Ln-O-N axis. 120 empirical formula Pdj formula weight, amu 1676.90 space group Pi a, A 9.2940(10) b , A 11.1879(10) c, A 16.4544(10) a, d e g 81.462(10) P , d e g 76.945(10) Y, d e g 83.230(10) vol, A' 1641.9(3) Z 1 p (calcd), mg m"' 1.696 crystal size, mm 0.19 X 0.19 X 0.15 r, “C -100 radiation (X,A) MoKa (0.71073) fi, mm'* 2.860 scan mode q-29 29 limits, deg 4.70 - 49.92 ±h -11 , 11 ±k -13, 13 ±1 -19, 19 no. o f rfln s measd 11107 no. o f unique rfln s 5701 no. of variables 352 JÎJ* tI> 2 o (D] 0.0286 wJ%/ (a ll data) 0.0745 GooF 1.064 • R, = El |F.|-|F,| I/SIFJ *’ wJîj = (S[w(Fo"-F,,*)^]/S[w(Fo*)*] }*/* Table 16. Crystallographic data for {(DMF),oGd 2|Pd(CN) 4]3}flo, 11. 121 Atom X y z U(eq)* Gd 6892(1) 6476(1) 2291(1) 27(1) Pd(l) 11848(1) 3869(1) 3086(1) 22(1) Pd(2) 10000 10000 0 23(1) C{11) 10381(5) 5140(4) 2692(3) 34(1) N{11) 9487(4) 5846(4) 2491(3) 45(1) C{12) 13451(5) 4995(4) 2790 (3) 28(1) N(12) 14441(4) 5573(3) 2628(2) 33(1) C(13) 13294(5) 2611(4) 3506(4) 44(1) N(13) 14157(5) 1930(4) 3761(4) 80(2) C(14) 10298(5) 2695(4) 3378(3) 31(1) N(14) 9431(5) 2001(4) 3550(3) 48(1) C(21) 9020(5) 8701(4) 826(3) 32(1) N(21) 8426(4) 7966(4) 1296(3) 47(1) C(22) 11994(5) 9226(4) 147(3) 37(1) N(22) 13138(5) 8778(5) 212(3) 61(1) 0(1) 6566(3) 5516(3) 3709(2) 35(1) C(l) 6210(5) 4519(4) 4109(3) 33(1) N(l) 6787(4) 3979(3) 4739(2) 36(1) C(1A) 6357(6) 2807(5) 5167(3) 54(1) C(1B) 7974(6) 4511(5) 4980(3) 54(1) 0(2) 7497(4) 4452(3) 2054(2) 49(1) C(2) 7178(6) 3391(5) 2210(3) 49(1) N(2) 7937(6) 2489(4) 1838 (3) 61(1) C(2A) 7515(11) 1246(6) 2094(4) 94(3) C(2B) 9299(9) 2695(8) 1239(5) 101(3) 0(3) 7172(4) 7912(3) 3160(2) 48(1) C(3) 8096(6) 7981(4) 3582(5) 68(2) K(3) 8004(5) 8803(4) 4092(3) 59(1) C(3A) 6775(6) 9700(5) 4227(4) 56(1) C(3B) 9179(8) 8832(6) 4546(6) 95(3) 0(4) 5048(4) 8077(3) 2173(3) 63(1) C(4) 3709(10) 8226(8) 2200(5) 34(2) N(4) 2608(12) 9014(11) 2538(7) 37(3) C(4A) 2922(11) 9811(9) 3077(6) 47(3) C(4B) 1185(11) 9102(9) 2362(6) 45(3) C(4') 4875(9) 9032(8) 1660(5) 28(2) N(4') 3653(9) 9745(7) 1844(5) 36(2) C(4A') 3425(13) 10933(11) 1345(7) 49(3) C(4B') 2470(30) 9310(20) 2503(15) 85(9) 0(5) 6555(4) 6332(5) 930(2) 72(1) C(5) 6332(10) 7384(8) 381(5) 29(2) N(5) 6620(9) 7189(7) -412(5) 41(2) C(5A) 7165(16) 5932(13) -648(9) 67 (4) C(5B) 6330(15) 8226(13) -1074(9) 66(4) C(5') 5797(10) 6367(8) 395(5) 37(2) (to be continued) Table 17. Atomic coordinates ( x 10*) and equivalent isotropic displacement parameters (A^ x 10^) for {(DMF),qGd 2[Pd(CN)j 3}»,1 1 . 122 Table 17. (continued) N(5') 5953(9) 5847(7) -318(5) 41(2) C(5A') 7131(15) 4876(12) -497(8) 73(4) C(5B') 4927(12) 6208(10) -864(7) 56(3) * U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. 123 Bond Lengths Gd-0(2) 2.337(3) N(l)-C(IB) 1.466(7) Gd-0(4) 2.346(3) 0(2)-C(2) 1.232(6) Gd-0(5) 2.361(4) C(2)-N(2) 1.308(6) Gd-0(3) 2.375(3) N(2)-C(2B) 1.437(10) Gd-O(l) 2.387(3) N(2)-C(2A) 1.464(9) Gd-N(21) 2.488(4) 0(3)-C(3) 1.236(7) Gd-N(11) 2.512(4) C(3)-N(3) 1.317(8) Gd-N(12)#l 2.514(3) N(3)-C(3A) 1.429(7) Pd(l)-C(13) 1.987(5) N(3)-C(3B) 1.461(7) Pd(l) -C(ll) 1.992(5) 0(4)-C(4) 1.228(9) Pd(l)-C(14) 1.994(4) 0(4)-C(4') 1.278(9) Pd(l)-C(12) 1.994(4) C(4) -N(4) 1.345(14) Pd(2)-C(21) 1.988(4) N(4)-C(4B) 1.406(15) Pd(2)-C(21)#2 1.988(4) N(4) -C(4A) 1.442(15) Pd(2)-C(22)#2 2.001(5) C(4')-N(4') 1.311(11) Pd(2)-C(22) 2.001(5) N(4')-C(4B') 1.43(3) C(ll)-N(ll) 1.147(6) N(4')-C(4A') 1.475(14) C(12)-N(12) 1.147(5) 0(5)-C(5') 1.240(9) N(12)-Gd#3 2.514(3) 0(5)-C(5) 1.399(9) C(13)-N(13) 1.146(6) C(5)-N(5) 1.318(12) C(14)-N(14) 1.145(6) N(5)-C(5B) 1.513(16) C(21)-N(21) 1.143(5) N(5)-C(5A) 1.513(16) C(22)-N(22) 1.142(6) C(5')-N(5') 1.356(11) 0(1)-C(l) 1.248(5) N(5')-C(5B') 1.438(13) C(l)-N(l) 1.311(6) N(5')-C(5A') 1.461(15) N(1)-C(1A) 1.447(6) Angles 0(2)-Gd-0(4) 141.32(13) 0(2)-Gd-N(12)#1 75.46(12) 0(2)-Gd-0(5) 72.68(15) 0(4)-Gd-N(12)#l 72.53(12) 0(4)-Gd-0(5) 80.26(17) 0(1)-Gd-N(ll) 75.86(12) 0(2)-Gd-0(3) 142.95(12) 0(5)-Gd-N(12)#l 78.81(12) 0(4)-Gd-0(3) 72.72(13) 0(3)-Gd-N(12)#1 116.59(12) 0(5)-Gd-0(3) 141.79(15) 0(1)-Gd-N(12)#l 73.41(11) 0(2)-Gd-0(l) 80.09(12) N(21)-Gd-N(12)#l 143.88(13) 0(4)-Gd-0 (1) 110.29(13) N(ll)-Gd-N(12)#l 137.72(12) 0(5)-Gd-0(1) 145.07(13) C(13)-Pd(l)-C(ll) 178.7(2) 0(3)-Gd-0(l) 71.41(11) C(13)-Pd(l)-C(14) 90.54(17) 0(2)-Gd-N(21) 115.28(14) C(ll)-Pd(l)-C(14) 89.38(17) 0(4)-Gd-N(21) 81.01(12) C(13)-Pd(l)-C(12) 87.68(17) 0(5)-Gd-N(21) 72.73(15) C(ll)-Pd(l)-C(12) 92.42(16) 0(3)-Gd-N(21) 76.72(14) C(14)-Pd(l)-C(12) 178.01(16) 0(1)-Gd-N(21) 140.46(13) C(21)-Pd(2)-C(21)#2 180.0(2) 0(2)-Gd-N(ll) 71.20(13) C(21)-Pd(2)-C(22)#2 89.53(17) 0(4)-Gd-N(ll) 146.79(13) C(21)#2-Pd(2)-C(22)#2 90.47(17) 0(5)-Gd-N(ll) 114.01(15) C(21)-Pd(2)-C(22) 90.47(17) 0(3)-Gd-N(ll) 79.10(13) C(22)#2-Pd(2)-C(22) 180.0(3) N(21) -Gd-N(11) 75.65(12) N (ll)-C (ll)-Pd(l) 176.9(4) (to be continued) Table 18. Bond lengths (A) and angles (“) for {(DMF),oGd 2[Pd(CN)j 3}«, 11. 124 Table 18. (continued) C(ll)-N{ll)-Gd 152.0(3) C(3)-N(3)-C(3A) 122.3(4) N(12)-C(12)-Pd(l) 175.2(4) C(3)-N(3)-C(3B) 120.6(5) C(12)-N(12)-Gd#3 169.6(3) C(3A) -N(3) -C(3B) 117.0(5) N(13)-C(13)-Pd{l) 176.6(5) C(4)-0(4)-C(4') 75.1(6) N(14)-C(14)-Pd(l) 178.5(4) C(4)-0(4)-Gd 138.9(5) N(21)-C(21)-Pd{2) 178.4(4) C(4')-0(4)-Gd 136.7(5) C(21)-N(21)-Gd 174.1(4) 0(4)-C(4)-N(4) 134.0(9) N(22)-C(22)-Pd{2) 178.4(5) C(4)-N(4)-C(4B) 121.9(10) C (l)-0(1)-Gd 137.7(3) C(4)-N(4)-C(4A) 118.5(10) 0(1)-C(1)-N(1) 123.5(4) C(4B)-N(4) -C(4A) 119.6(10) 0(1)-C(1)-H(1) 118.2 0(4)-C(4')-N(4') 117.6(8) N(l) -C(l) -H(l) 118.2 C(4')-N(4’)-C(4B') 118.8(12) C(1)-N(1)-C(1A) 121.1(4) C(4')-N(4’)-C(4A') 121.6(8) C(l) -N(l) -C(IB) 120.1(4) C(4B')-N(4')-C(4A') 119.4(12) C(1A) -N(1)-C(1B) 118.6(4) C(5') -0(5) -C(5) 58.2(6) C(2)-0(2)-Gd 148.7(3) C(5’) -0(5) -Gd 153.7(5) 0(2)-C(2)-N(2) 124.8(6) C(5)-0(5)-Gd 120.1(5) 0(2)-C(2)-H(2) 117.6 N(5)-C(5)-0(5) 112.9(7) N(2)-C(2)-H(2) 117.6 C(5)-N(5)-C(5B) 118.9(9) C(2)-N(2)-C(2B) 119.5(6) C(5)-N(5)-C(5A) 120.2(9) C(2)-N(2)-C(2A) 121.0(6) C(5B)-N(5)-C(5A) 120.8(9) C(2B)-N(2)-C(2A) 119.1(5) 0(5)-C(5')-N(5') 134.7(8) C(3)-0(3)-Gd 133.1(3) C(5')-N(5')-C(5B') 120.3(8) 0(3)-C(3)-N(3) 124.7(5) C(5')-N(5')-C(5A') 118.9(8) 0(3)-C(3)-H(3) 117.7 C(5B')-N(5')-C(5A') 120.8(9) N(3)-C (3)-H(3) 117.7 Symmetry transformations used to generate equivalent atoms : #1 x-l,y,z #2 -x+2,-y+2,-z #3 x+l,y,z 125 3. Synthesis and infrared spectral studies of {(DMF), 2La2[Pd(CN)j 3}., 12 The quantitative synthesis of the one-dimensional array, {(DMF),2La2[Pd(CN)j 3}«, 12 was carried out via the metathesis reaction of a 2 to 3,6 molar ratio ofLaCl, to K2Pd(CN)J'H 2 0 in DMF at room temperature (eqn. 11). 2GdCl3 + 3K2lPd(CN)4]H20— {(DMF)ioGd2[Pd(CN)4]3}. + 6 KCl + 3 H2O (11) The reaction mixture was stirred for IS days at room temperature under a N 2 atmosphere to guarantee complete removal of chloride as KCl. The low solubility of LaCls also contributed to the long reaction time. Colorless chunky X-ray quality crystals of {(DMF),2La2[Pd(CN) 4]3}« were grown from the viscous oil that resulted from concentrating the DMF solution. Drying of the crystals under dynamic vacuum for 12 to 14 hours at room temperature gave a colorless solid. Elemental analysis for the solid confirmed the loss of two DMF molecules per empirical unit. The solid state Nujol mull infrared spectrum of 12 is consisistent with the spectrum of the structural type C complex, {(DMF), 2Ce2[Pd(CN) 4]3}« (fig. 47a).™ The two stretches at 2166 cm ' and 2151 cm ' are shifted relative to K 2[Pd(CN) 4] and are assigned to the stretching modes of the bridging cyanides. The stretching band of the terminal cyanides of [Pd(CN) 4]**, 2134 cm ' is split into two bands, 2133 cm ' and 2127 cm '. This splitting was also observed in the solid state Nujol mull infrared spectrum of the complex, {(DMF), 2Ce2[Pd(CN) 4]3}„.™ Not surprisingly, the DMF solution infrared spectrum of 12 is different fram its solid state infrared spectrum indicating that different species are present in solution and in the solid state. Interestingly, the DMF solution infrared spectrum shows a similar pattern to that of a type B structure such as {(DMF),oGd 2[Pd(CN) 4]3},.“''" This was also 126 observed in the DMF solution infrared spectrum of {(DMF), 2Ce2[Pd(CN) 4]3}«.™ On the other band, the DMF solution infrared spectrum of the complex, {(DMF),2Ce2[Ni(CN)4]j}*, which belongs to the same C structural class, is nearly identical to that of a type A complex.™ Thus, the solution infrared spectra of type C complexes seem to he determined by the transition metals of [M(CN) 4]^’, (M = Ni, Pd) anions. When the transition metal is palladium, the DMF solution infrared spectrum resembles one for a type B complex, and when the transition metal is nickel, the spectrum is similar to that of a type A complex. This was also observed in the DMF solution infrared spectra of type A and B complexes. The DMF solution infrared spectrum of 12 shows four stretching hands (fg. 47h). The absorption hand at 2125 cm ' is assigned to the terminal cyanides since it shows up in the nonhridging cyanide stretching region of K 2[Pd(CN) 4] (2125 cm ')." The presence of three other higher absorption hands, 2159 cm ', 2141 cm ' and 2133 cm ' suggests that partial ionization occurs to produce some ion-paired complexes. 4. Molecular structure of {(DMF),2La2[Pd(CN) 4]3}«, 12 The crystal structure of 12 was solved by Dr. Shengming Liu. Crystallographic data for 12 are given in Table 19 and atomic coordinates are listed in Table 20. Selected bond lengths and bond angles are reported in Table 21. 12 falls under structural type C among the three types of structures of one-dimensional array cyanide bridged lanthanide(in)-transition metal complexes and is isomorphous with the structures of {(DMF),2Ce2[M(CN)4]3}„ (M = Ni, Pd).™ The type C structure is different from type A or B structure but is close to the type A structure. The crystal structure of 12 is a zigzag 127 2250 2200 2150 2100 2050 Waveflumtien(cm*') (a) 2250 2200 2150 2100 2050 Wavenumbefslcm*') (b) Figure 47. (a) Solid-state infiared spectrum and (b) solution infiared spectrum of {(DMF),2La,[Pd(CN)4]3}c.,12. 128 Figure 48. Molecular structure of a portion of the one-dimensional array {(DMF)„La^[Pd(CN) 4]3}o.,1 2 . 129 chain fotming a one-dimensional array that crystallizes in the triclinic space group. Pi (fig. 48). The cyanide-bridged "diamond"-shaped LajPdj metal cores, which are similar to those observed in type A structures, are formed by two cis-bridging [Pd(CN)J^' anions. These "diamond"-shaped LajPd 2 metal cores are then linked through La(in) ions by the trans-bridging cyanide ligands of the [Pd(CN)J^ anions to give a zigzag chain one-dimensional array. This chain is different from the linear chain one-dimensional array of structural type A.“’® The coordination geometry around each La(m) ion is a slightly distorted mono capped square antiprism (fig. 49a and fig. 49b). This is also different fiom structural type A, in which each Ln(III) ion has a slightly distorted square antiprismatic geometry. For 12, each Ln(III) ion is coordinated to six oxygen atoms from the DMF ligands and three nitrogen atoms from the bridging cyanide ligands of the [Pd(CN)J^ anions. One nitrogen atom (N21) from a bridging cyanide ligand of a trans-bridging [Pd(CN)J^' anion and three oxygen atoms (04,05, and 06) from the DMF ligands occupy the vertices of one of the square bases of the square antiprism. Two nitrogen atoms (N11 and N24) from the cyanide ligands of[Pd(CN)J^ and two oxygen atoms (02 and 03) from the DMF molecules occupy the vertices of the upper square base that is capped by an oxygen atom (01) of a DMF. Two of the coordinated nitrogen atoms (N11 and N24) share one edge of the upper square base. One, N11, is fit)m a cyanide ligand of a cis-bridging [Pd(CN) 4]^* and the other, N24, comes from a cyanide of a trans-bridging [Pd(CN) 4]^*. N24, on the upper base, and N2I, on the lower base, share an edge of the square antiprism, but N il and N21 do not 130 (a) c« Icu 04 'CM cm C3I CM CM (b) Figure 49. Monocapped square antiprismatic geometry around the La(III) ion in {(DMF),2La2[Pd(CN) 4]3}co, 1 2 [(a) shows the coordination geometry more clearly]. 131 em pirical formula Pdj fo r m u la w e ig h t, amu 1786.41 space group Pi a, A 11.4762(10) b , A 12.5675(10) c, A 13.9467(10) a, deg 97.464(10) P, deg 109.508(10) Y , deg 102.113(10) v o l , A’ 1809.6(2) Z 1 p (calcd), mg m' 1.639 c r y s t a l size, mm 0.27 X 0.27 X 0.15 T, “C -1 2 3 radiation (\, A) MoKa (0.71073) p , mm 1.953 scan mode w at S5/-55 28 lim its, deg 5.02 - 50.06 -13, 13 ±k -14, 14 ±1 -16, 16 no. of rflns measd 60949 no. of unique rflns 6384 no. of variables 398 R* [I> 2 o (D ] 0.0282 vRj*‘ ( a l l d a ta ) 0.0746 GooF 1.077 * R, = Sl|Fj-|FJ|/S|Fj “ wJ%; = {Z[w(F/-F/)']/2[w(F,')'] Table 19. Crystallographic data for {(DMF), 2La2[Pd(CN)J]}», 12. 132 Atom X y z U(eq)' L a d ) 2307(1) 2904(1) 2429(1) 14(1) Pdd) 0 5000 5000 18(1) Pd(2) 2778(1) -1302(1) 659(1) 17(1) 0(1) 1273(2) 4309(2) 1557(2) 25(1) C(l) 255(4) 4550(3) 1479(3) 23 (1) N (l) 24(3) 5504(3) 1312(2) 24(1) CdA) 999(4) 6406(4) 1236(4) 38(1) C(1B) -1205(4) 5719(4) 1206(3) 35(1) 0(2) 2384(2) 2797(2) 647(2) 24(1) C(2) 2902(4) 2258(3) 178(3) 23(1) N(2) 2268(3) 1471(3) -676(2) 26(1) C(2A) 2955(5) 868(4) -1161(4) 38(1) C(2B) 875(4) 1138(4) -1128(4) 39(1) 0(3) 3933(2) 4812(2) 2810(2) 29(1) C(3) 4288(4) 5139(3) 2136(3) 29(1) N(3) 5391(3) 5872(3) 2305(3) 27(1) C(3A) 6290(4) 6377(4) 3365(4) 41(1) C(3B) 5730(5) 6225(5) 1469(4) 52(1) 0(4) 4490(2) 2683(2) 2496(2) 28(1) C(4) 5253(3) 2108(3) 2562(3) 23(1) N(4) 6495(3) 2524(3) 2815(2) 25(1) C(4A) 7370(4) 1821(4) 2884(4) 44(1) C(4B) 7035(4) 3718(4) 3009(4) 39(1) 0(5) 3891(3) 3307(3) 4271(2) 34(1) C(5) 5030(4) 3486(3) 4831(3) 27(1) N(5) 5606(3) 2714(3) 5132(2) 26(1) C(5A) 4918(4) 1537(4) 4803(4) 38(1) C(5B) 6928(4) 2989(4) 5869(4) 51(1) 0(6) 1442(3) 1572(2) 3385(2) 31(1) C(6) 1437(3) 1539(3) 4260(3) 22(1) N(6) 1606(3) 693(3) 4719(2) 25(1) C(6A) 1627(4) 726(4) 5775(3) 35(1) C(6B) 1830(4) -275(4) 4200(4) 41(1) N(21) 2177(3) 802(3) 1661(2) 24(1) C(21) 2340(3) -10(3) 1310(3) 21(1) C(22) 4320(4) -1045(3) 1957(3) 25(1) N(22) 5183(3) -901(3) 2727(3) 38(1) C(23) 3304(4) -2497(3) -40(3) 28(1) N(23) 3629(4) -3152(3) -474(3) 45(1) C(24) 1145(3) -1659(3) -590(3) 20(1) N(24) 168(3) -1938(2) -1262(2) 22(1) N (ll) 1353(3) 3967(3) 3639(2) 26(1) C(ll) 855(3) 4352(3) 4133(3) 21(1) (to be continued) Table 20. Atomic coordinates ( x 10*) and equivalent isotropic displacement parameters (A^ x 10^) for ((DMF)„La,[Pd(CN) 4l^}«, 12. 133 Table 20. (continued) C(12) -103(3) 6271(3) 4277(3) 24(1) N(12) -183(3) 7013(3) 3881(3) 36(1) • U(eq) is defined as one th ird of the trace of the orthogonalized Uij tensor. 134 Bond Lengths L a d ) -0(2) 2.503(2 N(2)-C(2A) 1.459(5) L a d ) -0(5) 2.513(3 0 (3 )-C(3) 1.226(5) Lad) -0(6) 2.516(3 C(3)-N(3) 1.327(5) Lad)-0(1) 2.545(2 N(3)-C(3B) 1.439(6) L a d ) -0(4) 2.550(2 N(3)-C(3A) 1.454(5) Lad)-0(3) 2.578(3 0 (4 )-C(4) 1.236(4) L a d ) - N ( ll) 2.664(3 C(4)-N(4) 1.316(5) Lad) -N(21) 2.672(3 N(4)-C(4B) 1.448(5) Lad) -N(24)#l 2.673(3 N(4)-C(4A) 1.459(5) P d ( l)- C d l) 1.989(3 0 ( 5 )-C(5) 1.233 (5) Pdd) -Cdl)#2 1.989(3 C(5)-N(5) 1.320(5) Pd(l)-C(12) 2.000(4 N(5)-C(5A) 1.455(5) Pdd)-C(12)#2 2.000(4 N(5)-C(5B) 1.457(5) Pd(2)-C(23) 1.991(4 0 ( 6 )-C(6) 1.229(5) Pd(2)-C(21) 1.995(4 C(6)-N(6) 1.325(5) Pd(2)-C(22) 1.996(4 N(6)-C(6B) 1.449(6) Pd(2)-C(24) 2.002(4 N(6)-C(6A) 1.460(5) 0 ( 1 ) -C( 1) 1.241(4 N(21)-C(21) 1.152(5) C (l)-N ( 1) 1.314(5 C(22)-N(22) 1.153(5) N (l)-C ( IB) 1.455(5 C(23)-N(23) 1.154(5) N (l)-C ( lA) 1.458(5 C(24)-N(24) 1.143(5) 0 ( 2 ) -C( 2) 1.246(4 N(24)-La(l)#l 2.673(3) C(2)-N( 2) 1.318(5 Ndl) -C(ll) 1.153(5) N(2)-C( 28) 1.451(5 C(12)-N(12) 1.148(5) Angles 0(2) -L a d ) -0(5) 137.12 9) 0(6) -Lad) -N(21) 68.38(9) 0(2) -L a d ) -0(6) 136.28 9) 0(1)-La(l)-N(21) 130.79(9) 0(5)-Lad)-0(6) 71.27 10) 0(4) -Lad) -N(21) 68.17(9) 0(2) -L a d ) -0(1) 69.66 8) 0(3)-La(l)-N(21) 134.91(9) 0(5) -L a d ) -0(1) 125.20 9) N(ll)-La(l)-N(21) 137.89(10) 0(6) -L a d ) -0(1) 127.45 9) 0(2)-La(l)-N(24)#l 79.93(9) 0(2) -L a d ) -0(4) 70.88 9) 0(5)-La(l)-N(24)#l 141.48(10) 0(5) -L a d ) -0(4) 68.30 9) 0(6) -L a d ) -N (24)#l 72.58(9) 0(6) -L a d ) -0(4) 109.01 9) 0(1)-La(l)-N(24)#l 69.88(9) 0(1) -L a d ) -0(4) 123.52 9) 0(4)-La(l)-N(24)#l 137.82(9) 0(2) -L a d ) -0(3) 82.45 9) 0(3)-La(l)-N(24)#l 137.30(9) 0 ( 5 )-L a d ) -0(3) 71.10 10) N(ll)-La(l)-N(24)#l 83.43(9) 0(6) -L a d ) -0(3) 139.87 9) N(21)-La(l)-N(24)#l 74.26(9) 0(1) -L a d ) -0(3) 67.55 8) Cdl) -Pdd) -C(ll)#2 180.000(1) 0(4) -L a d ) -0(3) 68.65 9) C(ll)-Pd(l)-C(12) 91.71(15) 0(2) -L a d ) -N (ll) 138.88 9) C(ll)#2-Pd(l)-C(12) 88.29(15) 0(5) -L a d ) - N d l) 72.72 9) C(ll)-Pd(l)-C(12)#2 88.29(15) 0(6) -L a d ) -N (ll) 71.05 9) C(ll)#2-Pd(l)-C(12)#2 91.71(15) 0(1) -L a d ) - N d l) 69.34 9) C(12)-Pd(l)-C(12)#2 180.000(1) 0(4)-Lad) -Ndl) 138.11 9) C(23)-Pd(2)-C(21) 174.94(16) 0(3) -L a d ) - N d l) 84.92 9) C(23)-Pd(2)-C(22) 90.85(15) 0(2)-Lad) -N(21) 71.85 9) C(21)-Pd(2)-C(22) 89.19(14) 0(5)-Lad) -N(21) 103.85 10) C(23)-Pd(2)-C(24) 89.24(15) (to be continued) Table 21. Bond lengths (A) and angles O for {(DMF), 2La2[Pd(CN) 4]3}«, 12. 135 Table 21. (continued) C{21)-Pd(2)-C(24) 91.18(14) C(4B)-N(4)-C(4A) 117.6(3) C(22)-Pd(2)-C(24) 174.81(15) C(5)-0(5)-La(l) 145.3(3) C(l)-0(1)-La(l) 132.1(2) 0(5)-C(5)-N(5) 125.3(4) 0(1)-C(1)-N{1) 125.0(3) C(5)-N(5)-C(5A) 121.4(3) C(1)-N(1)-C(1B) 121.9(3) C(5)-N(5)-C(5B) 122.5(3) C(1)-N(1)-C(1A) 121.3(3) C(5A)-N(5)-C(5B) 116.0(3) C{1B)-N(1)-C(1A) 116.7(3) C(6)-0(6)-La(l) 140.1(2) C{2)-0(2)-La(l) 131.8(2) 0(6)-C(6)-N(6) 124.4(4) 0{2)-C(2)-N(2) 124.3(3) C(6)-N(6)-C(6B) 120.7(3) C(2)-N(2)-C(2B) 121.5(3) C(6)-N(6)-C(6A) 121.4(3) C{2)-N(2)-C{2A) 120.4(3) C(6B)-N(5)-C(6A) 117.9(3) C{2B)-N(2)-C{2A) 118.0(3) C(21) -N (21)-La(l) 166.8(3) C{3)-0(3)-La{l) 121.7(2) N(21) -C(21) -Pd(2) 173.2(3) 0{3)-C(3)-N{3) 125.7(4) N(22)-C(22)-Pd(2) 177.5(4) C(3)-N(3)-C(3B) 122.3(4) N(23) -C(23) -Pd(2) 176.5(4) C{3)-N(3)-C(3A) 120.1(3) N(24)-C(24)-Pd(2) 173.7(3) C{3B)-N(3)-C(3A) 117.5(4) C(24)-N(24)-La(l)#l 163.0(3) C{4)-0(4)-La(l) 150.5(3) C(ll)-N(ll)-La(l) 174.5(3) 0(4)-C(4)-N(4) 123.8(3) N(ll)-C(ll)-Pd(l) 179.1(3) C(4)-N(4)-C(4B) 120.1(3) N(12)-C(12)-Pd(l) 177.8(3) C(4)-N(4)-C(4A) 122.3(3) Symmetry transformations used to generate equivalent atoms: #1 - x , - y , -2 #2 -X,-y + l,-z + l 136 The average La-0 bond length is 2.534(4) À and the average La-N bond length is 2.670(0) A for 12. For comparison, the average Ce-0 bond length is 2.520(1) A and the average Ce-N bond length is 2.642(3) A for {(DMF), 2Ce2[Pd(CN) 4]3}«.™ This agrees well with decrease in size of the Ln(III) ions due to the lanthanide contraction.^ The coordination geometry around each Pd(H) ion is approximately square planar. The Pd-C and CN average bond lengths are 1.994(9) A and 1.151(1) A while the C-Pd-C bond angles range from 88.3(2)“ to 91.7(2)“ for 12. 5. Syntheses and infrared spectral studies of {(DMF);Ln[Pd(CN) 4]Cl}«, (Ln = La, 13; Gd, 14) The one-dimensional arrays, {(DMF);Ln[Pd(CN) 4]Cl}., (Ln = La, 13; Gd, 14) were synthesized quantitatively from LnClj and K 2[Pd(CN)J in a 2 to 3 molar ratio. The starting material, K 2[Pd(CN)J was prepared by heating K%[Pd(CN)4]'3H20 at 160 -170 “C for several hours.” During this drying process, black decomposition product was observed. Therefore, LnCl,, (Ln = La, 13; Gd, 14) and K 2[Pd(CN)J reacted as 1 to 1 ratio rather than a 2 to 3 ratio (eqn. 12). LnCIa + K2[Pd(CN) 4l > {(DMF)5Ln[Pd(CN) 4]CI}. + 2KCI (12) Ln = La, 13; Gd, 14 Colorless chunlgr X-ray quality crystals of {(DMF);La[Pd(CN)^]Cl}. and {(DMF)jGd[Pd(CN) 4]Cl}a were grown from the viscous oil that resulted from the removal of the DMF under dynamic vacuum. The crystals were pumped on for 12 to 14 hours at room temperature to produce colorless solids. Surprisingly, the colorless solid 137 6om 13 retained all five DMF molecules per empirical unit as determined by elemental analysis. Elemental analysis for the colorless solid 14 showed the loss of half a DMF molecule per empirical unit. The solid state Nujol mull infirared spectra of 13 and 14 show similar CN stretching patterns, indicating that their structures are isomorphous (fig. 50a). Their spectra resemble the cyanide stretching patterns of the complex, {(DMF);Sm[Ni(CN)JCl}..' The absorption band at 2148 cm ' of 13 is assigned to the bridging cyanide stretch. The other band at 2129 cm ' of 13 is attributed to a terminal cyanide vibrational mode. Likewise, the stretching band at 2158 cm ' of 14 is assigned to the band of bridging cyanide. The absorption band of the nonbridging cyanides of [Pd(CN)J^', 2134 cm ' is split into two bands, 2131 cm ' and 2129 cm '. The DMF solution infiared spectra of 13 and 14 are different fiom their solid state infiared spectra, suggesting the existence of distinct species in solution and solid. Interestingly, the DMF solution infiared spectra of 13 and 14 are nearly identical to those of type C and B complexes such as {(DMF), 2La2[Pd(CN)J]}. and {(DMF),oGd 2[Pd(CN)J;}„ respectively, implying the existence of the similar species in solution. In comparison, the DMF solution infiared spectrum of the complex, {(DMF)jSm[Ni(CN)4]Cl}., which belongs to the same type of structure, shows an almost identical spectrum to the type A complex, {(DMF),oSm 2[Ni(CN)4]3},.® Transition metals seem to determine cyanide stretching patterns in type A, B, and C complexes."^*”' ™ The DMF solution infiared spectra of 13 and 14 are similar due to the presence of the same [Pd(CN) 4]^' anion. The solution spectra of 13 and 14 show four stretching bands 138 2250 2200 2150 2100 2050 WavmumlMts (cm-') (a) 2250 Im " 2150 2100 2050 Wavenuniben(cm'') (b) Figure 50. (a) Solid-state infrared spectra and (b) solution infrared spectra of {(DMF)sLn[Pd(CN)JCl}ao, (Ln = La, 13; Gd, 14). 139 (fig. so b ). The absorption bands at 2125 cm ' for 13 and 14 are assigned to the terminal cyanides. The presence o f the other higher absorption bands, 2159 cm ', 2141 cm ' and 2133 cm ' for 13 and 2164 cm ', 2142 cm ' and 2135 cm ' for 14 indicates that partial ionization occurs to yield some ion-paired complexes containing bridging cyanides. 6. Molecular structures of {(DMF)jLn[Pd(CN)4]Cl}«, (Ln = La, 13; Gd, 14) The crystal structure of13 was solved by Dr. Jianping Liu. The crystal structure of 14 was solved by Dr. Jianping Liu and Dr. Bin Du. Crystallographic data for 13 and 14 are shown in Table 22 and 25 and atomic coordinates for 13 and 14 are listed in Table 23 and 26. Selected bond distances and bond angles for 13 and 14 are listed in Table 24 and 27. Unlike 11 and 12, the structures of13 and 14 consist of one-dimensional arrays that crystallize in the monoclinic space groups, P2,/n and P2,/c (fig. 51a and fig. 51b). The structures of13 and 14 are isomorphous with each other and with the structures, {(DMF)5Sm[Pd(CN) 4]Cl}«.® Both arrays, 13 and 14, have the asymmetric unit, {(DMF)%Ln[Pd(CN)JzCl}, (Ln = La, Gd). The two Pd atoms in the asymmetric unit are located on inversion centers. The inversion operation on two Pd atoms gives the repeating unit, {(DMF);Ln[Pd(CN) 4]2Cl}, (Ln = La, Gd). The repeating unit is translated along the crystallographic c axis to give a zigzag single strand chain forming a one-dimensional array. The coordination geometry around each Ln(m) ion is a slightly distorted square antiprism (fig. 52a and fig. 52b). Each Ln(lII), (Ln = La, Gd) ion is coordinated to five oxygen atoms fit)m the DMF ligands and two nitrogen atoms fit)m two bridging cyanide 140 N2I C2I iVfi (a) (b) Figure S1. Molecular structures of a portion of the one-dimensional arrays: (a) {(DMF);La[Pd(CN)JCl}., 13 and (b) (DMF);Gd[Pd(CN)JCl}., 14. 141 ligands of two [Pd(CN) 4]^'anions. In addition, it is also bound to one chloride. Each nitrogen atom is located on one of the square bases of the square antiprism and each shares an edge with chloride ion. The five oxygen atoms from the DMF ligands occupy the remaining vertices of the square antiprism. The La(III) ion in {(DMF)jLa[Pd(CN) 4]Cl}, has a eight-coordinate square antiprismatic coordination geometry, different from the mono-capped square antiprismatic coordination geometry in {(DMF),M[Pd(CN)4]3}„. The average La-0 bond distance is 2.482(1)  and the average La-N bond distance is 2.675(9)  for 13. The average Gd-0 bond distance is 2.397(1)  and the average Gd-N bond distance is 2.537(3)  for 14. The coordination geometry around the Pd(II) ion is approximately square planar. The C-Pd-C bond angle ranges from 88.2(2)" to 91.8(2)" for 13 and from 89.3(2)" to 90.7(2)" for 14. The Pd-C-N and Ln-N-C bond angles for 13 and 14 are almost linear except for the La-N(l 1)-C(11) bond angle [169.6(4)"] in 13 and the Gd-N(21)-C(21) bond angle [171.8(3)"] in 14. The average Pd- C and CN bond lengths are 2.022(6)  and 1.140(7) À for 13 and 1.997(5)  and 1.145(6) À for 14 and they are considered normal. 142 01 Cl (a) C3B N3 (b) Figure 52. Square antiprismatic geometry around (a) the La(m) ion in {(DMF);La[Pd(CN)JCl}., 13 and (b) the Gd(m) ion in {(DMF);Gd[Pd(CN)JCl}., 14. 143 empirical formula Ci,H,sClLaN,OsPd formula weight, amu 750.32 space group P2i/c a, k 7.5828(10) b, A 22.1789(10) c, A 17.8413(10) 3 , d e g 99.070(10) v o l , A' 2963.0(4) Z 4 p (calcd), mg m"' 1.682 crystal size, mm 0.38 X 0.27 X 0.23 r, *C -100 radiation (X,A) MoKa (0.71073) M, mm"^ 2.162 scan mode 0—20 20 lim its , deg 4.62 - 49.92 ±h -9, 9 ±k -26, 26 ±1 -2 1 , 21 no. of rflns measd 20109 no. of unique rfln s 5171 no. of variedjles 325 R* [I> 2 o (D ] 0.0338 (a ll data) 0.0875 GooF 1.026 ' & = 21 l / S I F j " wFz = (2[w(F,"-F/)']/Z[w(F/)'] Table 22. Crystallographic data for {(DMF)jLa[Pd(CN) 4]Cl}«, 13. 144 Atom X y z U(eq)* La 3923(1) 2495(1) -905(1) 24(1) Pd(l) 5000 5000 0 23(1) Pd(2) 5000 0 0 22(1) Cl 2025(2) 2390(1) 344(1) 46(1) 0(1) 915(4) 2939(2) -1392(2) 38(1) 0(1) 74(7) 3275(2) -1014(3) 41(1) N(l) -454(5) 3822(2) -1207(2) 31(1) C(1A) -1243 (8) 4208(3) -690(3) 54(2) C(1B) -65(8) 4097(3) -1889(3) 51(2) 0(2) 4442(5) 3082(2) -2045(2) 43(1) 0(2) 3548(7) 3273(2) -2640(3) 34(1) N(2) 3500(5) 3837(2) -2865(2) 30(1) 0(2A) 2435(7) 4031(2) -3569(3) 39(1) 0(2B) 4496(8) 4302(3) -2405(3) 52(2) 0(3) 2490(5) 1830(2) -1923(2) 55(1) N(3) 2661(7) 1176(2) -2866(3) 45(1) 0(3) 2276(10) 1312(3) -2187(4) 11(2) 0(3A) 2419(12) 556(4) -3169(5) 30(2) 0(3B) 3888(15) 1604(5) -3241(7) 44(3) 0(30) 2940(40) 1730(16) -2861(19) 192(13) 0(3D) 1880(40) 759(13) -2373(16) 169(10) 0(3E) 2360(30) 920(11) -3659(14) 134(8) 0(4) 6621(5) 2053(2) -1352(2) 36(1) 0(4) 7886(7) 1774(2) -979(3) 32(1) N(4) 8292(5) 1208(2) -1092(2) 34(1) 0(4A) 7248(8) 848(2) -1678(3) 46(1) 0(4B) 9697(8) 899(3) -574(3) 49(2) 0(5) 6504(5) 2641(2) 89(2) 40(1) 0(5) 7088(7) 2851(2) 712(3) 37(1) N(5) 7612(5) 2532(2) 1330(2) 33(1) 0(5A) 7533(9) 1879(3) 1302(4) 61(2) 0(5B) 8369(12) 2796(3) 2044(4) 84(2) N (ll) 4014(6) 3662(2) -476(2) 34(1) 0(11) 4320(6) 4155(2) -305(3) 27(1) 0(12) 3275(7) 5336(2) -859(3) 32(1) N(12) 2291(7) 5543(2) -1350(3) 48(1) N(21) 2083(7) -334(2) -1393(3) 50(1) 0(21) 3138(7) -219(2) -884(3) 31(1) N(22) 4393(6) 1367(2) -419(2) 33(1) 0(22) 4617(6) 869(2) -259(3) 28(1) *U(eg) is defined as one th ird of the trace of the orthogonalized Uij tensor. Table 23. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ x 10^) for {(DMF)jLa[Pd(CN) 4]CI}», 13. 145 Bond Lengths La-0 (5) 2.446(3) 0(3)-C(3C) 1.77(3) L a -0 (3) 2.457(3) N(3)-C(3C) 1.25(3) L a -0 (2) 2.496(3) N(3)-C(3) 1.324(8) L a -0 (4) 2.509(3) N(3)-C(3D) 1.46(3) La-O(l) 2.511(3) N(3)-C(3A) 1.476(10) La-N(22) 2.654(4) N(3)-C(3E) 1.51(2) La-N(11) 2.696(4) N(3)-C(3B) 1.552(12) La-Cl 2.8476(14) C(3)-C(3D) 1.29(3) Pd(l)-C(ll) 1.998(4) C(3)-C(3C) 1.66(3) Pd(l)-C(ll)#l 1.998(4) C(3A) -C(3E) 1.19(2) Pd(l)-C(12)#l 1.996(5) C(3A) -C(3D) 1.60(3) Pd(l)-C(12) 1.996(5) C(3B) -C(3C) 1.10(3) Pd(2)-C(21)#2 2.004(5) C(3B)-C(3E) 1.98(3) Pd(2)-C(21) 2.004(5) 0 ( 4 )-C(4) 1.244(6) Pd(2)-C(22)#2 1.993(5) C(4)-N(4) 1.317(6) Pd(2)-C(22) 1.993(5) N(4) -C(4A) 1.448(6) 0 ( 1 )-C (l) 1.247(6) N(4) -C(4B) 1.464(7) C (l)-N (l) 1.306(6) 0(5)-C(5) 1.223(6) N d )-C (IB ) 1.433(7) C(5) -N(5) 1.317(6) N (l)-C d A ) 1.454(6) C(5)-H(5) 0.9500 0 ( 2 )-C(2) 1.242(6) N(5)-C(5B) 1.439(7) C(2)-N(2) 1.313(6) N(5)-C(5A) 1.450(7) C(2)-H(2) 0.9500 N(ll)-C(ll) 1.149(6) N(2)-C(2A) 1.447(6) C(12)-N(12) 1.153(6) N(2)-C(2B) 1.453(6) N(21)-C(21) 1.139(6) 0(3)-C (3) 1.242(8) N(22)-C(22) 1.145(6) Angles 0(5)-La-0(3) 145.62(12) N(22)-La-N(11) 144.69(12) 0(5)-La-0(2) 108.11(12) 0 (5 )-La-Cl 83.58(10) 0(3)-La-0(2) 79.59(14) 0 ( 3 )-La-Cl 108.09(11) 0(5)-La-0(4) 71.51(11) 0 ( 2 )-La-Cl 147.57(8) 0(3)-La-0(4) 79.53(12) 0 ( 4 )-La-Cl 139.03(8) 0(2)-La-0(4) 72.77(11) 0 ( 1 )-La-Cl 76.07(9) 0(5)-La-0(l) 141.11(11) N(22)-La-Cl 74.08(9) 0(3)-La-0(l) 73.02(11) N(ll)-La-Cl 81.34(9) 0(2)-La-0(1) 76.40(12) C(ll)-Pd(l)-C(ll)#l 180.00(9) 0(4)-La-0(1) 141.72(11) C(ll)-Pd(l)-C(12)#l 88.24(18) 0(5)-La-N(22) 80.60(12) C(ll)#l-Pd(l)-C(12)#l 91.76(18) 0(3)-La-N(22) 72.31(13) C(ll)-Pd(l)-C(12) 91.76(18) 0(2)-La-N(22) 136.66(12) C(ll)#l-Pd(l)-C(12) 88.24(18) 0(4)-La-N(22) 70.21(12) C(12)#l-Pd(l)-C(12) 180.000(1) 0(1)-La-N(22) 123.43(12) C(21)#2-Pd(2)-C(21) 180.0(3) 0(5)-La-N(ll) 71.68(11) C(21)#2-Pd(2)-C(22)#2 89.58(18) 0(3)-La-N(ll) 140.80(12) C(21)-Pd(2)-C(22)#2 90.42(18) 0(2)-La-N(ll) 74.38(12) C(21)#2-Pd(2)-C(22) 90.42(18) 0(4)-La-N(11) 118.64(12) C(22)#2-Pd(2)-C(22) 180.0(4) 0(1)-La-N(ll) 72.72(12) C(l)-0(1)-La 124.1(3) (to be continued) Table 24. Bond lengths (A) and angles (“) for {(DMF)sLa|Pd(CN) 4]Cl}oo, 13. 146 Table 24. (continued) C(21)-Pd(2)-C(22) 89.58(18) 0(3E)-0(3A) -N(3) 67.9(13) 0(1) -C(l)-M(l) 125.0(5) 0(3E)-0(3A) -0(3D) 118.6(17) 0(I)-C(1)-H(1) 117.5 N(3)-0(3A) -0(3D) 56.6(11) N(l) -C(l)-H(l) 117.5 0(30)-0(3B)-N(3) 52.8(19) C{1)-N(1)-C(1B) 121.6 4) 0(30)-0(3B)-C(3E) 92(2) C(1)-N(1)-C(1A) 121.2 4) N(3)-0(3B)-0(3E) 48.7(8) C(1B) -N(l) -C(IA) 116.6 4) 0(3B)-0(30) -N(3) 83(2) C(2)-0{2)-La 137.7 3) 0(3B)-0(30) -0(3) 127(3) 0(2)-C(2)-N(2) 124.9 5) N(3)-0(30)-0(3) 51.9(13) 0(2)-C(2)-H{2) 117.5 0(3B)-0(30) -0(3) 149(3) N(2)-C(2)-H(2) 117.5 N(3)-0(30)-0(3) 94(2) C(2)-N(2)-C(2A) 122.2 4) 0(3)-0(30)-0(3) 42.3(9) C(2)-M(2)-C(2B) 121.1 4) 0(3)-0(3D)-N(3) 57.0(13) C(2A) -N(2)-C(2B) 116.6 4) 0(3)-0(3D)-0(3A) 114(2) C(3)-0(3)-C(3C) 63.9 12) N(3)-0(3D)-C(3A) 57.4(11) C(3)-0(3)-La 148.5 4) 0(3A) -0(3E) -N(3) 65.2(13) 0(30-0(3)-La 130.1 11) 0(3A) -0(3E) -0(3B) 107.1(16) 0(30) -N (3)-0(3) 80.2 16) N(3)-0(3E)-0(3B) 50.7(8) 0(30)-N(3)-0(3D) 135(2 0(4)-0(4)-La 128.5(3) 0(3)-N(3)-0(3D) 55.0 11) 0(4)-0(4)-N(4) 124.9(5) 0(30)-N(3)-0(3A) 158.6 17) 0(4)-0(4)-H(4) 117.5 0(3)-N(3)-0(3A) 120.9 6) N(4)-0(4)-H(4) 117.5 0(3D)-N(3)-0(3A) 66.0 12) 0(4)-N(4)-0(4A) 121.5(4) 0(30) -N(3) -C(3E) 112.2 18) 0(4)-N(4)-0(4B) 120.9(4) 0(3)-M(3)-0(3E) 157.2 10) 0(4A)-N(4)-0(4B) 117.3(4) 0(3D) -N(3)-0(3E) 108.2 15) 0(5)-0(5)-La 147.5(4) 0(3A) -N(3)-0(3E) 46.8 9) 0(5)-0(5)-H(5) 125.0(4) 0(30) -N(3)-0(3B) 44.7 15) 0(5)-C(5)-H(5) 117.5 0(3)-N(3)-0(3B) 119.2 6) N(5)-0(5)-H(5) 117.5 0(3D)-N(3)-0(3B) 166.3 12) 0(5)-N(5)-C(5B) 123.2(5) 0(3A) -N(3) -0(3B) 117.4 7) 0(5)-M(5)-C(5A) 120.2(4) 0(3E)-N(3)-0(3B) 80.6 10) 0(5B)-N(5)-0(5A) 116.5(5) 0(3)-0(3)-0(3D) 170.0 15) 0(11)-N(11)-La 169.7(4) 0(3)-0(3)-N(3) 121.6 6) N (ll)-0(11)-Pd(l) 176.7(4) 0(3D)-0(3)-N(3) 68.0 13) N(12)-0(12)-Pd(l) 178.4(4) 0(3)-0(3)-0(30 73.8 13) N(21)-C(21)-Pd(2) 178.9(5) 0(3D)-0(3)-0(30) 115.5 18) 0(22)-N(22)-La 175.2(4) N(3)-0(3)-0(30) 47.9 12) N(22)-0(22)-Pd(2) 179.0(4) Symmetry transformations used to generate equivalent atoms: #1 -x+l,-y+l ,-2 #2 -X+1,- -y,-z 147 em pirical formula Ci,H,sClGdN,0;Pd formula weight, amu 768.66 space group P2i/n a , k 7.755(3) b , A 17.810(7) c , A 21.576(6) P, d e g 92.72(3) v o l , A' 2977(2) Z 4 p (calcd), mg m"' 1.715 crystal size, mm 0.60 X 0.50 X 0.30 T, °C -60 radiation (X,A) MoKa (0.71073) p , mm’‘ 2.945 s c a n m ode 0-26 26 lim its, deg 4.42 - 49.96 ±h -5, 9 ±k -7, 21 ±1 -25, 25 no. of rflns measd 5753 no. of unique rflns 5224 no. of variables 329 R/ [I>2o(I)] 0.0259 wJ?/ (a ll data) 0.0712 GooF 1.088 * R, = SI |Fj-lF^| I/SIFJ “ wRz = (S[w(F/-P/)']/S[w(F.^)"] Table 25. Crystallographic data for {(DMF);Gd[Pd(CN)JCl}., 14. 148 Atom X y z U(eq)* Gd 9045(1) 4140(1) 2475(1) 23(1) Pd(l) 10000 5000 5000 26(1) Pd(2) 10000 5000 0 25(1) Cl 6989(2) 5377(1) 2430(1) 49(1) N (ll) 9351(5) 4545(2) 3607(2) 35(1) C(ll) 9542(5) 4718(2) 4114(2) 30(1) N(12) 12648(6) 6214(2) 4568(2) 49(1) C(12) 11690(6) 5771(2) 4734(2) 35(1) N(21) 9274(4) 4623(2) 1381(2) 33(1) C(21) 9537(5) 4781(2) 883 (2) 28(1) N(22) 12028(7) 6477(3) 342(2) 70(1) C{22) 11289(7) 5938(3) 233 (2) 42(1) 0(1) 11595(4) 3574(2) 2015(1) 38(1) C(l) 12805(5) 3915(2) 1791(2) 36(1) N (l) 13379(5) 3795(2) 1231(2) 38(1) C(1A) 12615(7) 3239(3) 818(2) 52(1) C(1B) 14702(6) 4286(3) 984(3) 54(1) 0(2) 7662(4) 3216(2) 1836(1) 38(1) 0(2) 7931(5) 2883(2) 1351(2) 35(1) N(2) 7194(5) 2243(2) 1184(2) 37(1) C(2A) 7673(8) 1858(3) 622(3) 64(2) C(2B) 5959(7) 1878(3) 1574(2) 54(1) 0(3) 9664(4) 3017(2) 3048(1) 36(1) 0(3) 8798(5) 2465(2) 3198(2) 34(1) N(3) 8657(5) 2228(2) 3769(2) 35(1) 0(3A) 9472(7) 2635(3) 4291(2) 51(1) 0(3B) 7743(8) 1541(3) 3914(2) 59(2) 0(4) 6402(4) 3744(2) 2939(1) 40(1) 0(4) 5701(5) 4071(2) 3365(2) 37(1) N(4) 4654(5) 3763(2) 3743(2) 44(1) 0(4A) 4169(10) 2990(4) 3675(4) 106(3) 0(4B) 3985(7) 4181(3) 4255(2) 62(2) 0(5) 11307(4) 4996(2) 2592(1) 44(1) 0(5) 11996(5) 5517(2) 2887(2) 34(1) N(5) 12711(5) 6099(2) 2630(2) 35(1) 0(5A) 12713(8) 6159(3) 1954(2) 55(1) 0(5B) 13691(7) 6653(3) 2999(2) 49(1) • U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. Table 26. Atomic coordinates ( x 10^) and equivalent isotropic displacement parameters (A^ x 10^) for {(DMF);Gd[Pd(CN)JCl}«, 14. 149 Gd-0(5) 2.329(3) 0 (1 )-C (l) 1.236(5) Gd-0(2) 2.370(3) C (l)-N (l) 1.324(5) Gd-0{3) 2.388(3) N(1)-C(1A) 1.441(6) Gd-0(4) 2.428(3) N (l)-C d B ) 1.468(6) Gd-O(l) 2.469(3) 0 (2 )-C(2) 1.230(5) Gd-N(21) 2.527(3) C(2)-N(2) 1.318(5) Gd-N(11) 2.547(3) N(2)-C(2A) 1.456(6) Gd-Cl 2.7184(14) N(2)-C(2B) 1.458(6) Pd(l)-C(ll)#l 1.993(4) 0 (3 )-C(3) 1.241(5) Pd(l)-C(ll) 1.993(4) C(3)-N(3) 1.313(5) Pd(l)-C(12) 2.001(5) N(3)-C(3B) 1.457(6) Pd(l)-C(12)#l 2.001(5) N(3) -C(3A) 1.457(6) Pd(2)-C(21) 1.995(4) 0 (4 )-C(4) 1.237(5) Pd(2)-C(21)#2 1.995(4) C(4) -N(4) 1.299(6) Pd(2)-C(22) 1.998(5) N(4)-C(4A) 1.434(7) Pd(2)-C(22)#2 1.998(5) N(4)-C(4B) 1.448(6) N(ll)-C(ll) 1.138(5) 0 (5 )-C(5) 1.233(5) N(12)-C(12) 1.152(6) C(5)-N(5) 1.311(5) N(21)-C(21) 1.138(5) N(5)-C(5B) 1.458(5) N(22)-C(22) 1.138(6) N(5)-C(5A) 1.463(6) Angles 0(5)-Gd-0(2) 146.61 10) 0 (1 )-Gd-Cl 142.71(7) 0(5)-Gd-0(3) 111.17 12) N(21)-Gd-Cl 75.95(8) 0(2)-Gd-0(3) 78.11 11) N(ll)-Gd-Cl 80.36(9) 0(5) -Gd-0(4) 142.38 10) C(ll)#l-Pd(l)-C(ll) 180.000(1) 0(2) -Gd-0(4) 70.76 10) C(ll)#l-Pd(l)-C(12) 90.7(2) 0(3)-Gd-0(4) 72.32 10) C(ll)-Pd(l)-C(12) 89.3(2) 0(5)-Gd-0(l) 72.37 11) C(ll)#l-Pd(l)-C(12)#l 89.3(2) 0(2) -Gd-O(l) 80.32 11) C(ll)-Pd(l)-C(12)#l 90.7(2) 0(3)-Gd-0(l) 73.83 10) C(12)-Pd(l)-C(12)#l 180.0 0(4)-Gd-0(l) 139.04 10) C(21)-Pd(2)-C(21)#2 180.0 0(5)-Gd-N(21) 77.97 11) C(21)-Pd(2)-C(22) 91.9(2) 0(2)-Gd-N(21) 75.09 11) C(21)#2-Pd(2)-C(22) 88.1(2) 0(3)-Gd-N(21) 138.38 10) C(21)-Pd(2)-C(22)#2 88.1(2) 0 (4 )-Gd-N(21) 125.58 11) C(21)#2-Pd(2)-C(22)#2 91.9(2) 0(1)-Gd-N(21) 70.74 11) C(22)-Pd(2)-C(22)#2 180.0 0(5)-Gd-N(ll) 71.08 11) C(ll)-N(ll)-Gd 177.8(3) 0(2)-Gd-N(11) 140.68 10) N(ll) -C(ll)-Pdd) 177.0(4) 0(3)-Gd-N(11) 74.57 11) N(12)-C(12)-Pd(l) 178.5(4) 0(4)-Gd-N(11) 74.29 11) C(21) -N(21)-Gd 171.8(3) 0(1)-Gd-N(ll) 117.48 11) N(21)-C(21)-Pd(2) 176.9(3) N(21)-Gd-N(ll) 142.35 11) N(22)-C(22)-Pd(2) 177.4(4) 0 (5 )-Gd-Cl 84.87 10) C(l)-0(1)-Gd 126.5(3) 0 (2 )-Gd-Cl 107.03 9) Od)-Cd)-N(l) 124.9(4) 0 (3 )-Gd-Cl 143.18 7) Od)-Cd)-H(l) 117.6(3) 0 (4 )-Gd-Cl 75.22 8) Nd)-C(l)-Hd) 117.6(3) (to be continued) Table 27. Bond lengths (A) and angles (“) for {(DMF);Gdpd(CN)JCl}., 14. 150 Table 27. (continued) C(l) -N(1)-C(1A) 121.9(4) N(3)-C(3A)-H(3A3) 109.5(3) C(1)-N(1)-C(1B) 120.4(4) N(3)-C(3B)-H(3B1) 109.5(3) C(1A) -N (l) -C(IB) 117.4(4) N(3)-C(3B)-H(3B2) 109.5(3) M(1)-C(1A) -H(lAl) 109.5(2) N(3)-C(3B)-H(3B3) 109.5(3) N(1)-C{1A) -H(1A2) 109.5(3) C(4)-0(4)-Gd 125.4(3) N(1)-C(1A) -H(1A3) 109.5(3) 0(4)-C(4)-N(4) 125.3(4) N(1)-C(1B)-H(1B1) 109.5(3) 0(4)-C(4)-H(4) 117.3(2) N(1)-C(1B)-H(1B2) 109.5(3) N(4)-C(4) -H(4) 117.3(3) N(1)-C(1B)-H(1B3) 109.5(3) C(4) -N(4) -C(4A) 120.7(5) C(2)-0(2)-Gd 137.7(3) C(4)-N(4)-C(4B) 121.2(4) 0(2) -C(2)-N(2) 124.2(4) C(4A) -N(4)-C(4B) 118.1(5) 0(2) -C(2)-H(2) 117.9(2) N(4)-C(4A) -H(4A1) 109.5(3) M(2)-C(2)-H(2) 117.9(2) N(4)-C(4A) -H(4A2) 109.5(4) C(2)-N(2)-C(2A) 120.7(4) N(4)-C(4A) -H(4A3) 109.5(4) C(2)-N(2)-C(2B) 121.1(4) N(4)-C(4B)-H(4B1) 109.5(3) C(2A)-N(2)-C(2B) 118.1(4) N(4)-C(4B)-H(4B2) 109.5(3) N(2)-C(2A)-H(2A1) 109.5(3) N(4)-C(4B)-H(4B3) 109.5(3) N(2)-C(2A)-H(2A2) 109.5(3) C(5)-0(5)-Gd 148.6(3) N(2)-C(2A)-H(2A3) 109.5(3) 0(5)-C(5)-N(5) 123.8(4) N(2)-C(2B)-H(2B1) 109.5(2) 0(5)-C(5)-H(5) 118.1(2) N(2)-C(2B)-H(2B2) 109.5(3) N(5)-C(5)-H(5) 118.1(2) N(2)-C(2B)-H(2B3) 109.5(2) C(5)-N(5)-C(5B) 121.5(4) C(3)-0(3)-Gd 134.4(3) C(5)-N(5)-C(5A) 120.1(4) 0(3)-C(3)-N(3) 124.7(4) C(5B)-N(5)-C(5A) 118.0(4) 0(3) -C(3)-H(3) 117.7(2) N(5)-C(5A)-H(5A1) 109.5(2) N(3) -C(3)-H(3) 117.7(2) N(5)-C(5A) -H(5A2) 109.5(3) C(3) -N(3)-C(3B) 122.4(4) N(5)-C(5A) -H(5A3) 109.5(3) C(3)-N(3)-C(3A) 120.9(4) N(5)-C(5B)-H(5B1) 109.5(2) C(3B)-N(3)-C(3A) 116.7(4) N(5)-C(5B)-H(5B2) 109.5(3) N(3)-C(3A) -H(3A1) 109.5(2) N(5)-C(5B)-H(5B3) 109.5(2) N(3)-C(3A) -H(3A2) 109.5(2) Symmetry trémsformations used to generate equivalent atoms: #1 -x+2,-y+1,-z+1 #2 -x+2,-y+1 ,-z 151 CHAPTER 6 EXPERIMENTAL 6.1. Apparatus See chapter 3.1 from 76 page to 80 page. 6.2. Solvents and Reagents 1) N, N-Dimethylformamide DMF (Fisher) was stirred over activated 4  molecular sieves for S days in a 1000-mL pyrex flask under vacuum. The flask was connected to a U-tube apparatus in the dry box. The DMF was then degassed under vacuum and then distilled at 70-80 °C into a 500-mL pyrex flask at -78 “C. 2) Molecular sieves Linde brand molecular sieves (4 A) were evacuated and heated to ISO "C under dynamic vacuum for 12 hours until no water evolved firom the molecular sieves. 3) Lanthanum trichloride LaCb (Strem) was used as received. 152 4) Gadolinium trichloride GdCh (Strem) was used as received. 5) Potassium tetracyanopalladiate (II) trihydrate K2Pd(CN)4*3H20 (Aldrich) was used as received. 6.3. Preparation of Starting Materials 1) Potassium tetracyanopalladate (II) monohydrate K2[Pd(CN)4]«H20 was prepared by drying K2[Pd(CN)4]*3H20 at 100 “C for several hours according to literature method^^ and stored in the dry box. 2) Potassium tetracyanopalladate (II) K2[Pd(CN) 4] was prepared from K2[Pd(CN)4]*3H20 under dynamic vacuum at 200 °C for 12 hours by the literature method^^ and stored in the dry box. 6.4. Reactions I) Preparation o f {(DMF)ioGd2[Pd(CN)4]3}«, 11 In the drybox, 0.2673 g (1.014 mmol) of GdCb and 0.5010 g (1.634 mmol) of K2[Pd(CN) 4]3*H 2O in a 2 to 3.2 ratio were placed in a 50-mL flask with DMF (ca. 30 mL) and a Teflon-coated magnetic stir bar. The reaction mixture was stirred for 15 days at room temperature under a N2 atmosphere. The reaction mixture was filtered leaving a white precipitate (KCl) and a colorless filtrate. The filtrate was concentrated until a viscous oil remained. The colorless chunky X-ray quality crystals of {(DMF)toGd 2[Pd(CN) 4l3} 153 molecule per empirical unit as determined by elemental analysis. Yield: nearly quantitative. Anal. Calculated for (DMF)9Gd2[Pd(CN)4]3: C, 29.21; H, 3.96; N, 18.34. Found: C, 29.29; H, 4.20; N, 18.09. IR (Nujol mull of crystals, vcn, cm'*): 2173,2160, 2135. 1R(DMF solution, v c n , cm'‘): 2163,2142,2135,2125. 2) Preparation of {(DMF)i2La2[Pd(CN)4]3}«, 12 In the drybox, 0.1017 g (0.4147 mmol) of LaCb and 0.2286 g (0.7454 mmol) of K2[Pd(CN)4]*H20 in a 2 to 3.6 molar ratio were added to a 50-mL flask with DMF (ca. 30 mL) and a Teflon-coated magnetic stir bar. The reaction mixture was stirred for 15 days at room temperature under a N 2 atmosphere. The reaction mixture was filtered leaving a white precipitate (KCl) on the frit and a colorless filtrate. The filtrate was concentrated until a viscous oil remained. Colorless chunky X-ray quality crystals of {(DMF)i2La2[Pd(CN) 4]3}« were formed after several days at room temperature. Drying of the crystals under dynamic vacuum for 12 to 14 hours at room temperature gave the colorless solid. Elemental analysis of the solid showed the loss of two DMF molecules per empirical unit. Yield: nearly quantitative. Anal. Calculated for (DMF)io La2[Pd(CN) 4]3: C, 30.76; H, 4.30; N, 18.79. Found: C, 30.26; H, 4.39; N, 18.57. IR (Nujol mull of crystals, vcn, cm'*): 2166,2151, 2133,2127. IR (DMF solution, vcn, cm'*): 2159,2141,2133,2125. 3) Preparation of {(DMF)sLa[Pd(CN)4]Cl}oo, 13 In the drybox, 0.1045 g (0.4261 mmol) o f LaCla and 0.1838 g (0.6367 mmol) o f K2[Pd(CN) 4] in a 2 to 3 molar ratio were placed in a flask with DMF (ca. 25 mL) and a Teflon-coated magnetic stir bar. The reaction mixture was stirred for 11 days at room 154 temperature under a N% atmosphere. The reaction mixture was filtered leaving a white precipitate (KCl) on the fiit and a colorless filtrate. The filtrate was concentrated until a viscous oil remained. Within 12 hours, colorless chunky X-ray quality crystals of {(DMF)sLa[Pd(CN) 4]Cl}« were formed at room temperature. Drying of the crystals under dynamic vacuum for 12 to 14 hours at room temperature gave the colorless solid. The colorless solid retained all five DMF ligands per empirical unit as determined from elemental analysis. Yield: nearly quantitative. Anal. Calculated for (DMF);La[Pd(CN) 4]Cl]: C, 30.41; H, 4.70; N, 16.80. Found: C, 30.78; H, 4.75; N, 17.57. IR (Nujol mull of crystals, vcn, cm '): 2148.31, 2129.02. IR (DMF solution, vcn, cm '): 2159,2141,2133,2125. 4) Preparation of {(DMF) 5GdPd(CN) 4]Cl}«, 14 In the drybox, 0.1191 g (0.4518 mmol) of GdCb and 0.1956 g (0.6775 mmol) of K2[Pd(CN) 4] in a 2 to 3 molar ratio were added to a flask with DMF (ca. 25 mL) and a Teflon-coated magnetic stir bar. The reaction mixture was stirred for 6 days at room temperature under a Nz atmosphere. The reaction mixture was filtered leaving a white precipitate (KCl) on the frit and a colorless filtrate. The filtrate was concentrated until a viscous oil remained. After 24 hours, colorless chunky X-ray quality crystals of {(DMF)sGd[Pd(CN) 4]Cl}o, were formed at room temperature. Elemental analysis of the colorless solid obtained from drying the crystals under dynamic vacuum for 12 to 14 hours at room temperature showed the loss of half DMF molecule per empirical unit. Yield: nearly quantitative. 155 Anal. Calculated for (DMF)4jGd[Pd(CN) 4]Cl: C, 28.71; H, 4.34; N, 16.26; Cl, 4.84. Found: C, 28.51; H, 4.52; N, 16.58; Cl, 3.19. IR (Nujol mull of crystals, v c n , cm 2158,2131,2129. IR (DMF solution, V cn , cm '): 2164,2142,2135,2125. 156 UST OF REFERENCES 1. Cotton, F. A.; Wilkinson, G.Advanced Inorganic Chemistry, 5* ed.; Wiley and Sons: New York, 1988. 2. Szabadvary, F. Handbook on the Physics and Chemistry o fRare Earths’, Gschneidner Jr., K. A. and Eyring, L., Eds.; Elsevier: Amsterdam, 1988, Vol. 11, Chap. 73. 3. Gschneidner Jr., K. A.; Daane, A. H. Handbook on the Physics and Chemistry o f Rare Earths Gschneidner Jr., K. A. and Eyring, L., Eds.; Elsevier: Amsterdam, 1988, Vol. 11, Chap. 78. 4. Evans, W. J. Polyhedron 1987, 6 ,803. 5. Moeller, T. Comprehensive Inorganic Chemistry; Bailar, J. C., Emeleus, H. J., Nyholm, R., Trotman-Dickenson, A. F., Eds.; Pergamon Press: Oxford, 1973, Vol. 4. 6. Huheey, J. E. Inorganic Chemistry, 3"* ed.; Harper & Row: New York, 1983, p.796. 7. Moeller, T. The Chemistry o fthe Lanthanides; Reinhold Book Corp.: New York 1963, Chap. 2. 8. Jorgensen, C. K. 7. Inorg. Nucl. Chem. 1955,7,301. 9. Pearson, R. G. J. Am. Chem. Soc. 1963, 8 5 ,3533. 10. Palenik, G. J.,Systematics and the Properties o f the Lanthanides; Sinha, S.P., Ed.; NATO ASI Ser. C, 1982, No. 109, Chap. 5. 11. Ascenso, J. R. and Xavier, A. V. Systematics and the Properties o f the Lanthanides; Sinha, S. P., Ed.; NATO ASI Ser. C, 1982, No. 109, Chap. 11. 12. Topp, N. E. The Chemistry o f the Rare-Earth Elements; Elsevier: Amsterdam, 1965, Chap. 12. 157 13. McClure, D. S.; Kiss, Z. / Chem. Phys. 1963, 3 9,3251. 14. Deacon, G. B.; MacKinnon, P. I.; Hambley, T. W.; Taylor, J. C. / Organomet.Chem. 1983, 259,91. 15. Zinnen, H. A.; Pluth, J. J.; Evans, W. J. J. Chem. Soc., Chem. Commun. 1980,810. 16. Lappert, M. P.; Yarrow, P. I. W.; Atwood, J. L.; Shakir, R.; Holton, J. J. Chem. Sac., Chem. Commun. 1980,987. 17. Tilley, T. D.; Andersen, R. A.; Spencer, S.; Ruben, H.; Zalkin, A.; Templeton, D. H. Inorg. Chem. 1980, 19,2999. 18. Tilley, T. D.; Andersen, R. A.; Spencer, B.; Zalkin, A. Inorg. Chem. 1982, 21, 2647. 19. Wayda, A. L.; Dye, J. L.; Rogers, R. D. Organometallics 1984, 3, 1605. 20. Evans, W. J.; Bloom, I.; Hunter, W. E.; Atwood, J. L. J. Am. Chem. Soc. 1981, 103, 6507. 21. Evans, W. J.; Grate, J. W.; Choi, H. W.; Bloom, I.; Hunter, W. E.; Atwood, J. L. J. Am. Chem. Soc. 1985, 107,941. 22. Evans, W. J.; Hughes, L. A.; Hanusa, T. P. Organometallics 1986, 5 , 1285. 23. Boncella, J. M.; Tilley, T. D.; Andersen, R. A. J. Chem. Soc., Chem. Commun. 1984,710. 24. Evans, W. J.; Hughes, L. A.; Hanusa, T. P. J. Am. Chem. Soc. 1984, 106,4270. 25. Wayda, A. L.; Mukeqi, I.; Dye, J. L. Organometaliics 1987, 6, 1328. 26. Manning, M. J.; Knobler, C. B.; Hawthorne, M. F. J. Am. Chem. Soc. 1988, IIO, 4458. 27. White, J. P. HI; Deng, H.; Shore, S. G./. Am. Chem. Soc. 1989, III, 8946. 28. White, J. P. HI; Shore, S. G. Inorg. Chem. 1992, 3 1 ,2756. 29. White, J. P. HI; Deng, H,; Shore, S. G. Inorg. Chem. 1991, 3 0 ,2337. 30. Greenwood, N. N. Comprehensive Inorganic Chemistry; Bailar, J. C., Emeleus, H. J., Nyholm, R., Trotman-Dickenson, A. P., Eds.; Pergamon Press: Oxford, 1973, Vol. 1. 158 31. Etourneau, J.J. Less-Common Met. 1985, 7/0,267. 32. Matthias, B. T.; Geballe, T. H.; Andres, K.; Corenzwit, E.; Hull, G.; Malta, J. P. Science 1968, 159,530. 33. Lafferty, J. M. J. Appl. Phys. 1951, 2 2, 299. 34. Tarascon, J. M.; Etourneau, J.; Dordor, P.; Hagenmuller, P.; Kasaya, M.; Coey, J. M. D. J. Appl. Phys. 1980, 5 1 ,574. 35. Guy, C. N.; Molnar, S.; Etourneau, J.; Fisk, Z.Solid State Communication 1980, 33, 1055. 36. White, J. P. IIL Ph. D. Dissertation, The Ohio State University, 1990. 37. Choplin, A.; Huang, L.; Theolier, A.; Gallegot, P.; Basset, J. M.; Siriwardane, U.; Shore, S. G.; Mathieu, R. J. Am. Chem. Soc. 1986, 108,4224. 38. Wunderlich, J. A.; Lipscomb, W. N. J. Am. Chem. Soc. 1960, 82,4428. 39. White, J. P. III; Deng, H.; Boyd, E. P.; Gallucci, J.; Shore, S. G. Inorg. Chem. 1994, 33, 1685. 40. Klanberg, P.; Muetterties, E. L. Inorg. Chem. 1966, 5,1955. 41. Z. Anorg. Allg. Chem. 1989, 571,21. 42. Shriver, D. P.; Dredzon, M. A. The Manipulation o f Air-sensitive Compounds, 2""* éd.; John Wiley and Sons: New York, 1969. 43. Hill, T. G.; Godfroid, R. A.; White, J. P. IH; Shore, S. G. Inorg. Chem. 1991, 30, 2952. 44. Kôster, R.; Seidel, G. Inorg. Synth. 1983, 2 2 , 198. 45. Howell, J. K.; Pytlewski, L. L.J. Less Comm. Metals 1969, 18,437. 46. (a) Deng, H. B.; Shore, S. G. J. Am. Chem. Soc. 1991, 113,8538. (b) Deng, H. B. Ph. D. Dissertation, The Ohio State University, 1990. 47. Beletskaya, I. P.; Voskoboynikov, A. Z.; Chuklanova, E. B.; Kirillova, N. I.; Shestakova, A. K.; Parshina, I. N.; Gusev, A. L; Magomedov, G. K.-I. J. Am. Chem. Soc. 1993, 115,3156. 159 48. Bailey, W. E.; Williams, R. J.; Milligan, W. O. Acta Cryst. 1973, B 29,1365. 49. Hulliger, F.; Landolt, M.; Vetsch, H. J. Solid State Chem. 1976, 18,283. 50. Hulliger, P.; Landolt, M.; Vetsch, H. J. Solid State Chem. 1976, 18,307. 51. Mullica, D. P.; Milligan, W. 0 .; Kouba, W. T.J. Inorg. Nucl. Chem. 1979, 4 1,967. 52. Mullica, D. P.; Perkins, H. 0.; Sappenfîeld, E. L.; Grossie, D. A. J. Solid State Chem. 1988, 74,9. 53. Mullica, D. P.; Perkins, H. 0.; Sappenfîeld, E. L. J. Solid State Chem. 1988, 74, 419. 54. Mullica, D. P.; Perkins, H. 0.; Sappenfîeld, E. L.; Leschnitzer, D. Acta Cryst. 1989, C45,330. 55. Petter, W.; Gramlich, V.; Hulliger, P. J. Solid State Chem. 1989,52,161. 56. Mullica, D. P.; Sappenfîeld, E. L. J. Solid State Chem. 1989, 8 2 ,168. 57. Gramlich, V.; Petter, W.; Hulliger, P. Acta Cryst. 1990, C46,724. 58. Dommann, A.; Vetsch, H.; Hulliger, P.; Petter, W. Acta Cryst. 1990, C 46,1992. 59. Beall, G. W.; Mullica, D. P.; Milligan, W. O.; Kouba, W. T. J. Inorg. Nucl. Chem. 1979,47,967. 60. Mullica, D. P.; Milligan, W. 0.; Oliver, J. D. Inorg. Nucl. Chem. Lett. 1979, 1 5 ,1. 61. Mullica, D. P.; Sappenfîeld, E. L.; Perkins, H. 0 . J. Solid State Chem. 1988, 73,65. 62. Milligan, W. G.; Mullica, D. P.; Perkins, H. O.Inorganica Chimica Acta 1982, 60, 35. 63. Mullica, D. P.; Sappenfîeld, E. L.; Perkins, H. O. J. Solid State Chem. 1989, 78, 301. 64. Mullica, D. P.; Sappenfîeld, E. L.; Cunningham, T. A. J. Solid State Chem. 1991, 97,98. 65. Klement, U. Z. Kristallogr. 1993, 208,285. 160 66. Klement, U. Z. Kristallogr. 1993, 208,288. Since no structural details were provided in this communication, crystallograpbic data and atomic coordinates that were available were used to calculate bond distances and angles for comparisons. 67. Glieman, G.; Yersin, H. Struct. Bonding 1985, 6 2 ,87 and references therein. 68. Knoeppel, D. W.; Shore, S. G. Inorg. Chem. 1996, 3 5 ,1747. 69. Knoeppel, D. W.; Liu, J.; Meyers, E. A.; Shore, S. G. Inorg. Chem. 1998, 37,4828. 70. Liu, J.; Knoeppel, D. W.; Liu, S.; Meyers, E. A.; Shore, S. G. Inorg Chem. In press. 71. Knoeppel, D. W.; Shore, S. G. Inorg. Chem. 1996, 3 5 ,5328. 72. Rath, A.; Aceves, E.; Mitome, J.; Liu, J.; Ozkan, U. S.; Shore, S. G. J. Mol. Cat. A 2 0 0 1 ,165, 103. 73. Kubas, G. J.; Jones, L. H.Inorg. Chem. 1974, 13,2186. 74. Catalyst Handbook, 2"^ ed.; Twigg, M. V. Ed.; Wolfe Publishing, Ltd.: Frome, 1989. 75. Sinfelt, J. H. Bimetallic Catalysts', John Wiley and Sons: New York, 1983. 76. Bigelow, J. H. Inorg. Syn. 1946, 2 , 345. 77. Otwinowsky, Z.; Minor, W. Processing of X-ray Dif&action Data Collected in Oscillation Mode. In Methods in Enzymology, Vol. 276: Macromolecular Crystallography, part A', Carter, C. W., Jr., Sweet, R. M., Eds.; Academic Press: New York, 1997; pp 307-326. 78. Blessing, R. H. Acta Crystallogr. 1995, A 51,33. 79. SHELXTL (version 5.10), Bruker Analytical X-ray Systems, 1997. 161