Ph.D. Thesis Advisor); for His Intellectual Guidance, Support and Inspiration

Home , Organoplatinum

SYNTHESIS AND CHARACTERIZATION OF LIGANDS AND TRANSITION METAL

COMPLEXES CONTAINING M-TERPHENYL SCAFFOLDS

LIQING MA

Submitted in partial fulfillment of the requirements

For the Degree of Doctor of Philosophy

Thesis Advisor: Professor John D. Protasiewicz

Department of Chemistry

CASE WESTERN RESERVE UNIVERSITY

January, 2007 CASE WESTERN RESERVE UNIVERSITY

SCHOOL OF GRADUATE STUDIES

We hereby approve the dissertation of

______Liqing Ma candidate for the Ph.D. degree *.

Thomas Gray (signed)______(chair of the committee)

Malcolm E. Kenny ______

M. Cather Simpson ______

Christoph Weder ______

John D. Protasiewicz ______

______

October 24, 2006 (date) ______

*We also certify that written approval has been obtained for any proprietary material contained therein.

To my Parents

i Table of Contents

Dedication………………………………………………………………………………………….i

Table of Contents………………………………………………………………………………….ii

List of Figures…………………………………………………………………………………..…v

List of Charts………………………………………………………………………… …………xii

List of Schemes………………………………………………………………………………….xiv

List of Tables…………………………………………………………………………………….xvi

Acknowledgements……………………………………………………………………………..xvii

List of Abbreviations…………………………………………………………………………..xviii

Abstract……………………………………………………………………………………….....xix

Chapter 1. General Information…………………………………………………………………1

1.1 Introduction………………………………………………………………………….1

1.2 Applications of Pincer Complexes…………………………………………………9

1.3 Synthesis of Pincer Ligands and Complexes……………………………………....21

1.4 Proposed Work……………………………………………………………………..24

1.5 Works Cited…………………………………………………………………….….29

Chapter 2. Synthesis and Characterization of PCP Pincer Ligands Based on m-Terphenyl

Scaffolds…………………………………………………………………………...35

2.1 Introduction………………………………………………………………………..35

2.2 Results and Discussion………………………………………………………...... 37

2.3 Conclusion………………………………………………………………………....43

2.4 Experimental……………………………………………………………………….44

2.5 Works Cited………………………………………………………………………..60

ii Chapter 3. A New Twist on PCP Diphosphine Pincer Complexes…………………………….62

3.1 Introduction………………………………………………………………………..62

3.2 Results and discussion……………………………………………………………..65

3.3 Conclusion……………………………………………………………………...….82

3.4 Experimental……………………………………………………………………….83

3.5 Works Cited………………………………………………………………………..99

Chapter 4. NCN Diimine Pincer Ligands and Complexes Bearing m-Terphenyl Scaffolds....102

4.1 Introduction. …………………………………………………………………...... 102

4.2 Results and discussion………………………………………………………...... 104

4.3 Conclusion…………………………………………………………………….…..114

4.4 Experimental……………………………………………………………………....115

4.5 Works Cited…………………………………………………………………….…141

Chapter 5. NCN Diamine Pincer Ligands and Complexes: Synthesis and Structural

Studies………………… …………………………………………………..……..144

5.1 Introduction……………………………………………………………………….144

5.2 Results and discussion………………………………………………………….....146

5.3 Conclusion………………………………………………………………………...159

5.4 Experimental………………………………………………………………………160

5.5 Works Cited……………………………………………………………………….167

Chapter 6. Efforts towards Resolution of Chiral Pincer Complexes………………………….170

6.1 Introduction…………………………………………………………………….…170

6.2 Results and discussion…………………………………………………………….172

6.3 Conclusion………………………………………………………………………...179

6.4 Experimental……………………………………………………………………....180

iii 6.5 Works Cited………………………………………………………………………189

Chapter 7. Self-Assembly of Cationic Palladium Complexes by Redistribution of Pyridine

Ligands………………………………...………………………………………….191

7.1 Introduction……………………………………………………………………….191

7.2 Experimental……………………………………………………………………....192

7.3 Results and discussion………………………………………………………….…195

7.4 Conclusion……………………………………………………………………...…202

7.5 Works Cited…………………………………………………………………….…203

Chapter 8. Conclusions………………………………………………………………………..205

Appendix 1. Crystal Structure Determinations and Tables of Bond Lengths and Angles……... 210

Bibliography……………………………………………………………………………………..295

iv List of Figures

Figure 2.1 1H NMR spectra of 2.9. Top: mixture of two isomers; bottom: one of the

isolated isomers.

Figure 2.2 An ORTEP drawing (40% probability thermal ellipsoids) of 2.13 with atom

labeling scheme.

Figure 2.3 An ORTEP drawing (40% probability thermal ellipsoids) of 2.15 with atom

labeling scheme.

1 Figure 2.4 H NMR spectrum of 2.8 (CDCl3, 400 MHz)

13 Figure 2.5 C NMR spectrum of 2.8 (CDCl3, 100 MHz)

1 Figure 2.6 H NMR spectrum of 2.9 (CDCl3, 400 MHz)

13 Figure 2.7 C NMR spectrum of 2.9 (CDCl3, 100 MHz)

1 Figure 2.8 H NMR spectrum of 2.10 (CDCl3, 400 MHz)

13 Figure 2.9 C NMR spectrum of 2.10 (CDCl3, 100 MHz)

1 Figure 2.10 H NMR spectrum of 2.11 (CDCl3, 400 MHz)

13 Figure 2.11 C NMR spectrum of 2.11 (CDCl3, 100 MHz)

1 Figure 2.12 H NMR spectrum of 2.12 (CDCl3, 400 MHz)

13 Figure 2.13 C NMR spectrum of 2.12 (CDCl3, 100 MHz)

31 Figure 2.14 P NMR spectrum of 2.13 (CDCl3, 162 MHz)

1 Figure 2.15 H NMR spectrum of 2.13 (CDCl3, 400 MHz)

31 Figure 2.16 P NMR spectrum of 2.14 (CDCl3, 162 MHz)

1 Figure 2.17 H NMR spectrum of 2.14 (CDCl3, 400 MHz)

31 Figure 2.18 P NMR spectrum of 2.15’ (CDCl3, 162 MHz)

1 Figure 2.19 H NMR spectrum of 2.15’ (CDCl3, 400 MHz)

v 13 Figure 2.20 C NMR spectrum of 2.15’ (CDCl3, 100 MHz)

31 Figure 2.21 P NMR spectrum of 2.15 (C6D6, 162 MHz)

1 Figure 2.22 H NMR spectrum of 2.15 (C6D6, 400 MHz)

1 Figure 3.1 H NMR spectra of 3.1 (CDCl3, 600 MHz) and detailed assignments

13 Figure 3.2 C NMR spectra of 3.1 (CDCl3, 150 MHz) and detailed assignments

Figure 3.3 ORTEP drawing (20% probability ellipsoids) of the molecular structure of 3.1.

Figure 3.4 ORTEP drawing (40% probability ellipsoids) of the molecular structure of 3b.

Figure 3.5 ORTEP drawing (40% probability ellipsoids) of the molecular structure of 3.3.

1 Figure 3.6 Variable temperature H NMR (600 MHz) of 3.1 in CD2Cl2 (top) and in

CDCl2CDCl2 (bottom)

Figure 3.7 Variable temperature 1H NMR (600 MHz, dmso-d6) of 3.1 for methylene

region

1 Figure 3.8 Variable temperature H NMR (600 MHz, CD2Cl2) of 3.1 for aromatic region

1 Figure 3.9 Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.1 for aromatic

region

Figure 3.10 Variable temperature 1H NMR (600 MHz, dmso-d6) of 3.1 for aromatic region

Figure 3.11 Variable temperature 1H NMR (600 MHz, toluene-d8) of 3.3 for alkyl region.

(methyl protons indicated by *)

Figure 3.12 Variable temperature 1H NMR (600 MHz, CDCl3) of 3.3 for alkyl region

31 Figure 3.13 Variable temperature P NMR (243 MHz, CDCl2CDCl2) of 3.3.

1 Figure 3.14 Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.3, alkyl region

1 Figure 3.15 Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.3, aromatic

region

31 Figure 3.16 P NMR spectrum of 3.1 (CDCl3, 162 MHz)

vi 1 Figure 3.17 H COSY spectrum of 3.1 (CDCl3, 600 MHz)

Figure 3.18 600 MHz 1H-detected 1H-13C correlation (HMQC) spectrum of 3.1

Figure 3.19 600 MHz 1H-detected 1H-13C correlation (HMBC) spectrum of 3.1

31 Figure 3.20 P NMR spectrum of 3.2 (CDCl3, 162 MHz)

1 Figure 3.21 H NMR spectrum of 3.2 (CDCl3, 400 MHz)

1 Figure 3.22 H NMR spectrum of 3.2, expansion of aromatic region (CDCl3, 400 MHz)

13 Figure 3.23 C NMR spectrum of 3.2 (CDCl3, 100 MHz)

13 Figure 3.24 C NMR spectrum of 3.2, expansion of alkyl region (CDCl3, 100 MHz)

13 Figure 3.25 C NMR spectrum of 3.2, expansion of aromatic region (CDCl3, 100 MHz)

31 Figure 3.26 P NMR spectrum of 3.3 (CDCl3, 162 MHz)

13 Figure 3.27 C NMR spectrum of 3.3 (CDCl3, 100 MHz)

13 Figure 3.28 C NMR spectrum of 3.3, expansion of aromatic region (CDCl3, 100 MHz)

13 Figure 3.29 C NMR spectrum of 3.3, expansion of alkyl region (CDCl3, 100 MHz)

31 Figure 3.30 P NMR spectrum of 3.4 (CDCl3, 162 MHz)

1 Figure 3.31 H NMR spectrum of 3.4 (CDCl3, 400 MHz)

1 Figure 3.32 H NMR spectrum of 3.4, expansion of aromatic region (CDCl3, 400 MHz)

13 Figure 3.33 C NMR spectrum of 3.4(CDCl3, 150 MHz)

13 Figure 3.34 C NMR spectrum of 3.4, expansion of aromatic region (CDCl3, 150 MHz)

Figure 4.1 ORTEP drawing of the molecule structure of 4.11 (40% probability ellipsoids).

Figure 4.2 ORTEP drawing of the molecule structure of 4.12 (40% probability ellipsoids).

Figure 4.3 ORTEP drawing of the molecule structure of 4.13 (40% probability ellipsoids).

Figure 4.4 ORTEP drawing of the molecule structure of 4.14 (40% probability ellipsoids).

Figure 4.5 Illustration showing how hindered rotation about N-Ar bond of complex 4.13

distinguishes methyl protons a and a’

vii 1 Figure 4.6 Temperature dependant H NMR (600 MHz, CDCl3) spectra of 4.13 (left), and

the simulated 1H NMR spectra (right) for resonances a and a’.

1 Figure 4.7 Temperature dependence H NMR (600 MHz, CDCl3) spectra of 4.12 (left),

and the simulated 1H NMR spectra (right)

Figure 4.8 Eyring plots of ln(k/T) vs. 1/T for complex 4.12 (■), and complex 4.13 (△)

1 Figure 4.9 H NMR spectrum of 4b (CDCl3, 400 MHz)

1 Figure 4.10 H NMR spectrum of 4b, aromatic region (CDCl3, 400 MHz)

13 Figure 4.11 C NMR spectrum of 4b (CDCl3, 100 MHz)

13 Figure 4.12 C NMR spectrum of 4b, aromatic region (CDCl3, 100 MHz)

1 Figure 4.13 H NMR spectrum of 4.5 (CDCl3, 400 MHz)

1 Figure 4.14 H NMR spectrum of 4.5, aromatic region (CDCl3, 400 MHz)

13 Figure 4.15 C NMR spectrum of 4.5 (CDCl3, 100 MHz)

13 Figure 4.16 C NMR spectrum of 4.5, aromatic region (CDCl3, 100 MHz)

1 Figure 4.17 H NMR spectrum of 4.7 (CDCl3, 400 MHz)

13 Figure 4.18 C NMR spectrum of 4.7 (CDCl3, 100 MHz)

1 Figure 4.19 H NMR spectrum of 4.8 (CDCl3, 400 MHz)

1 Figure 4.20 H NMR spectrum of 4.8, aromatic region (CDCl3, 400 MHz)

13 Figure 4.21 C NMR spectrum of 4.8 (CDCl3, 100 MHz)

13 Figure 4.22 C NMR spectrum of 4.8, aromatic region (CDCl3, 100 MHz)

1 Figure 4.23 H NMR spectrum of 4.9 (CDCl3, 400 MHz)

1 Figure 4.24 H NMR spectrum of 4.9, aromatic region (CDCl3, 400 MHz)

13 Figure 4.25 C NMR spectrum of 4.9 (CDCl3, 100 MHz)

13 Figure 4.26 C NMR spectrum of 4.9, aromatic region (CDCl3, 100 MHz)

1 Figure 4.27 H NMR spectrum of 4.10 (CDCl3, 400 MHz)

viii 13 Figure 4.28 C NMR spectrum of 4.10 (CDCl3, 100 MHz)

13 Figure 4.29 C NMR spectrum of 4.10, alkyl region (CDCl3, 100 MHz)

13 Figure 4.30 C NMR spectrum of 4.10, aromatic region (CDCl3, 100 MHz)

1 Figure 4.31 H NMR spectrum of 4.11 (CDCl3, 400 MHz)

1 Figure 4.32 H NMR spectrum of 4.11, aromatic region (CDCl3, 400 MHz)

13 Figure 4.33 C NMR spectrum of 4.11 (CDCl3, 100 MHz)

13 Figure 4.34 C NMR spectrum of 4.11, aromatic region (CDCl3, 100 MHz)

1 Figure 4.35 H NMR spectrum of 4.12 (CDCl3, 400 MHz)

1 Figure 4.36 H NMR spectrum of 4.12, aromatic region (CDCl3, 400 MHz)

13 Figure 4.37 C NMR spectrum of 4.12 (CDCl3, 100 MHz)

13 Figure 4.38 C NMR spectrum of 4.12, aromatic region (CDCl3, 100 MHz)

1 Figure 4.39 H NMR spectrum of 4.13 (CDCl3, 400 MHz)

1 Figure 4.40 H NMR spectrum of 4.13, aromatic region (CDCl3, 400 MHz)

13 Figure 4.41 C NMR spectrum of 4.13 (CDCl3, 100 MHz)

13 Figure 4.42 C NMR spectrum of 4.13, aromatic region (CDCl3, 100 MHz)

1 Figure 4.43 H NMR spectrum of 4.14 (CDCl3, 400 MHz)

1 Figure 4.44 H NMR spectrum of 4.14, aromatic region (CDCl3, 400 MHz)

13 Figure 4.45 C NMR spectrum of 4.14 (CDCl3, 100 MHz)

13 Figure 4.46 C NMR spectrum of 4.14, aromatic region (CDCl3, 100 MHz)

Figure 5.1 An ORTEP drawing (40% probability thermal ellipsoids) of 5.9 with atom

labeling scheme

Figure 5.2 ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.10

Figure 5.3 ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.11

ix Figure 5.4 ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.12

Figure 5.5 Illustration of the proximity of protons to the central benzene ring in complex

5.10

Figure 5.6 Variable temperature NMR spectra of complex 5.10 (CDCl3, 600 MHz)

Figure 5.7 Variable concentration NMR spectra of complex 5.10 (CDCl3, 600 MHz)

1 Figure 5.8 H NMR spectrum for ligand 5.9 (CDCl3, 400 MHz)

13 Figure 5.9 C NMR of ligand 5.9 (CDCl3, 100 MHz)

13 Figure 5.10 C NMR of ligand 5.9, aromatic region (CDCl3, 100 MHz)

1 Figure 5.11 H NMR spectrum for complex 5.10 (CDCl3, 400 MHz)

13 Figure 5.12 C NMR of complex 5.10 (CDCl3, 100 MHz)

13 Figure 5.13 C NMR of complex 5.10, aromatic region (CDCl3, 100 MHz)

Figure 6.1 ORTEP representation of the molecular structure of 6.15a.

Figure 6.2 ORTEP representation of the molecular structure of 6.15b. Only one of the

three independent molecules in the asymmetric unit is shown

Figure 6.3 Further view of complex 6.15a (top) and 6.15b (bottom) emphasizing the

proximity of methyne proton with the phenyl ring

Figure 6.4 Comparison of 1H NMR spectra of 6.15a (top) and 6.15b (bottom)

31 Figure 6.5 P NMR spectrum (CDCl3, 161.8 MHz) for diastereomers 6.10a and 6.10b

1 Figure 6.6 H NMR spectrum (CDCl3, 400 MHz) for diastereomers 6.10a and 6.10b

31 Figure 6.7 P NMR spectrum (CDCl3, 161.8 MHz) for diastereomers 6.12a and 6.12b

1 Figure 6.8 H NMR spectrum (CDCl3, 400 MHz) for ligand 6.14

13 Figure 6.9 C NMR spectrum (CDCl3, 100 MHz) for ligand 6.14

13 Figure 6.10 C NMR spectrum (CDCl3, 100 MHz, aromatic region) for ligand 6.14

1 Figure 6.11 H NMR spectrum (CDCl3, 400 MHz) for complex 6.15a

x 1 Figure 6.12 H NMR spectrum (CDCl3, 400 MHz, aromatic) for complex 6.15a

13 Figure 6.13 C NMR spectrum (CDCl3, 100 MHz) for complex 6.15a

13 Figure 6.14 C NMR spectrum (CDCl3, 100 MHz, aromatic) for complex 6.15a

1 Figure 6.15 H NMR spectrum (CDCl3, 400 MHz) for complex 6.15b

1 Figure 6.16 H NMR spectrum (CDCl3, 400 MHz, aromatic) for complex 6.15b

13 Figure 6.17 C NMR spectrum (CDCl3, 100 MHz) for complex 6.15b

13 Figure 6.18 C NMR spectrum (CDCl3, 100 MHz, aromatic) for complex 6.15b

Figure 7.1 An ORTEP drawing (30% probability thermal ellipsoids) of 7.3 with atom

labeling scheme.

Figure 7.2 Crystal structure of 7.3. Solvent molecules (THF)

1 Figure 7.3 H NMR (400 MHz, CD3CN) spectra of (a) solution of 7.2 showing

equilibrium mixture of 7.1, 7.2, and 7.3 (upper spectrum) (B) solution of 7.1

(middle spectrum) (C) solution of 7.2 and 0.5 equiv. 7.1 (lower spectrum). All

solutions in CD3CN

xi List of Charts

Chart 1.0 m-xylyl based pincer complex (left) and proposed pincer complexes bearing

m-terphenyl scaffolds (right)

Chart 1.1 Herrmann-Beller palladacycle

Chart 1.2 Examples of palladacycles with different donor atoms

Chart 1.3 First PCP pincer complex (right) reported by Shaw et al.

Chart 1.4 Phosphinite-palladium and iridium pincer complexes

Chart 1.5 Unsymmetrical pincer complexes

Chart 1.6 Tridentate carbene CNC, CCC pincer palladium complexes

Chart 1.7 Dendrimer supported nickel pincer complex

Chart 1.8 Examples of efficient pincer catalysts for Heck reactions

Chart 1.9 Example of SCS pincer complex

Chart 1.10 Reactive pincer catalysts for Suzuki-Miyaura coupling reactions

Chart 1.11 Diphosphine PCP iridium pincer complexes

Chart 1.12 Diphosphinite PCP iridium pincer complexes

Chart 1.13 Dimethylamino NCN pincer complexes

Chart 1.14 Ruthenium pincer complexes

Chart 1.15 Chiral PCP pincer complexes for asymmetric aldol reactions

Chart 1.16 Examples of m-xylyl based pincer complexes with twist angles listed

Chart 1.17 Target molecules containing C2 symmetric environment

Chart 1.18 BINAP

Chart 2.1 Examples of chiral PCP pincer ligands

Chart 2.2 BINAP

xii Chart 2.3 Diphosphine pincer ligand constructed with m-terphenyl

Chart 4.1 Twist angle Φ of pincer complexes

Chart 4.2 Examples of NCN diimine pincer complexes

Chart 5.1 NCN pincer ligand (left) and its complex (right)

Chart 5.2 Examples of chiral NCN pincer complexes

Chart 5.3 Previously reported m-terphenyl based PCP and NCN pincer complexes

Chart 6.1 Examples of chiral m-xylyl based pincer complexes

Chart 6.2 Examples of pincer complexes having twisted structures

xiii List of Schemes

Scheme 1.1 Potential modification sites of pincer ligands and complexes

Scheme 1.2 Synthesis of polymer supported pincer complexes

Scheme 1.3 Transfer dehydrogenation catalyzed by iridium pincer complexes

Scheme 1.4 Proposed mechanism for catalytic alkane dehydrogenation

Scheme 1.5 Alkane metathesis via tandem transfer dehydrogenation-olifen metathesis

Scheme 1.6 Kharasch addition, X = halogen; Y = H, halogen, CF3 or other electron negative

groups

Scheme 1.7 A proposed mechanism of Kharasch reaction catalyzed by NCN nickel pincer

complex

Scheme 1.8 Direct cyclometalation of NCN pincer ligand

Scheme 1.9 Oxidative addition of pincer ligand by low valent metal

Scheme 1.10 Transmetalation of aryllithium complex to transition metal pincer complex

Scheme 1.11 Transcyclometalation method to produce desired pincer complexes

Scheme 1.12 Interconversion of two atropisomers a and a’

Scheme 1.13 Construction of a new pincer complex bearing m-terphenyl scaffold

Scheme 1.14 Synthetic procedure for trans-spanning diphosphine palladium complex

Scheme 1.15 Proposed synthetic method to afford pincer complex by oxidative addition

Scheme 2.1 General synthetic routes for pincer ligands and complexes. (D = PR2, NR2, SR,

etc.)

Scheme 2.2 Synthesis of trans-spanning diphosphine ligand and palladium complex

Scheme 2.3 Synthesis of ligand precursors

Scheme 2.4 Synthesis of diphosphine ligands 2.13-2.15

xiv Scheme 3.1 Typical " pincer" binding and atropisomers

Scheme 3.2 Relationship between previous trans-spanning (left) and new pincer complexes

(right)

Scheme 4.1 Synthesis of diimine pincer ligands precursors

Scheme 4.2 Synthesis of palladium diimine pincer complexes

Scheme 4.3 Two different routes of oxidative addition of Pd(0) to Ar-X bond

Scheme 5.1 Synthesis of diamine NCN pincer ligand

Scheme 5.2 Synthesis of diamine NCN pincer complexes

Scheme 5.3 Proposed equilibrium of 5.10 in solution

Scheme 6.1 Reaction of PCP pincer complex with (S)-α –phenylethylamine

Scheme 6.2 Reaction of PCP pincer complex with (S)-α –tert-butylethylamine

Scheme 6.3 Synthesis of chiral NCN pincer complexes

Scheme 7.1 Synthesis of complex 7.2

Scheme 7.2 Ligand redistribution reaction involving 7.2

Scheme 8.1 Synthetic schemes for PCP and NCN pincer ligands

Scheme 8.2 Synthetic schemes for PCP and NCN pincer complexes

Scheme 8.3 Synthesis of chiral NCN pincer complexes

xv List of Tables

Table 1.1 Catalysis results of Heck reactions by complexes 17, 18 and 19

Table 1.2 Results of Heck reactions catalyzed by complex 8

Table 1.3 Selected results of Suzuki-Miyaura coupling reactions

Table 1.4 Results of transfer hydrogenation catalyzed by ruthenium pincer complexes

Table 1.5 Results of asymmetric aldol reactions catalyzed by chiral pincer complexes

Table 2.1 Selected bond lengths (Å) and angles (°) for 2.13 and 2.15

Table 3.1 Selected bond lengths (Å) and angles (°) for complexes 3.1-3.3

Table 4.1 Selected bond lengths (Å) and angles (°) of complexes 4.11-4.14

Table 5.1 Selected bond lengths (Å) and angles (o) of complex 5.10 (four independent

molecules in the asymmetric unit)

Table 5.2 Selected bond lengths (Å) and angles (o) of complex 5.11

Table 5.3 Selected bond lengths (Å) and angles (o) of complex 5.12

Table 5.4 1H NMR data for m-xylyl based NCN pincer complexes and complex 5.10

Table 7.1 Crystal Data and Structure Refinement for 7.3·2THF

Table 7.2 Selected bond lengths (Å) and angles (º) for complex 7.3•2THF

xvi Acknowledgements

Professor John D. Protasiewicz (Ph.D. Thesis Advisor); for his intellectual guidance, support and inspiration.

Professor Fred L. Urbach, Professor Thomas Gray, Professor Malcolm E. Kenny, Professor M.

Cather Simpson, Professor Christoph Weder; for being my Ph.D. committee and their guidance.

Professor Tong Ren and his student Weizhong Chen; for X-ray work.

Professor Allen D. Hunter and his previous student James B. Updegraff III (currently at CASE); for X-ray work.

Dr. Dale Ray; for assistant with NMR experiments.

Labmates: Dr. Thirupathi Natesan, Dr. Rhett C. Smith, Dr. Xufang Chen, Robert A. Woloszynek,

Vittal Babu G., Marlena P. Washington, Philip M. Imbesi, Stephen D. Wobser; for help.

National Science Foundation, Petroleum Research Fund (ACS) and Case Western Reserve

University Department of Chemistry; for funding.

xvii List of Abbreviations

Ar Aryl tBu tert-Butyl

Calcd. Calculated

COD 1,5-Cyclooctadiene

COSY Correlation Spectroscopy

Cy Cyclohexyl dba dibenzylideneacetone

HMBC Heteronuclear Multiple Bond Correlation

HMQC Heteronuclear Multiple Quantum Correlation iPr iso-Propyl

Me Methyl

Mes Mesityl

Ph Phenyl

R Alkyl

RT Room Temperature

Py Pyridin

THF Tetrahydrofuran

Xyl Xylyl

xviii SYNTHESIS AND CHARACTERIZATION OF LIGANDS AND TRANSITION METAL

COMPLEXES CONTAINING M-TERPHENYL SCAFFOLDS

Abstract

LIQING MA

t Diphosphine ligands 2,6-(2-CH2PR2C6H4)2C6H3Br (R = Ph, Cy, Bu), diimine ligands

2,6-{2-R’N=C(H)C6H4}2C6H3I (R’ = Ph, 2,6-Me2C6H3, 2,4,6-Me3C6H2, Cy, (S)-α-methylbenzyl) and the diamine ligand 2,6-(2-Me2NCH2C6H4)2C6H3I have synthesized and characterized. The reaction of these ligands with Pd2(dba)3 afforded new kinds of PCP and NCN pincer complexes.

These pincer complexes containing m-terphenyl scaffolds have been characterized by NMR spectroscopy and single crystal X-ray crystallography. Structure analyses of these pincer complexes reveal a C2 symmetric environment. In addition, this system shows the greatest

“twist” angle to date for pincer complexes. There has been no evidence of the interconversion of possible atropisomers even at elevated temperature, which indicates the high rigidity of these pincer complexes. Further more, the introduction of chiral imine groups was utilized for resolution of chiral pincer complexes having high degree of non-fluxionality.

xix Chapter 1. General Information

1.1 Introduction

Recent applications of pincer complexes include finding efficient catalysts for dehydrogenation of alkanes, sensors, Heck type coupling reactions, and activation of strong C-O and C-C bonds.1-4 These pincer compounds are predominantly constructed upon a m-xylyl

- framework ([2,6-(DCH2)2C6H3] , D = donor atoms or groups such as NR2, PR2, SR, etc. Chart

1.1, left). Efforts have been concentrated upon building new kinds of PCP/NCN metal complexes based on m-terphenyl scaffolds (Chart 1.0, right). These proposed pincer complexes contain three dimensional framework and C2 symmetric environment. Preparation of enantiomerically pure pincer complexes would have great potential in the application of catalytic asymmetric synthesis.

D D M D M D

Chart 1.0. m-xylyl based pincer complex (left) and proposed pincer complexes bearing m-terphenyl scaffolds (right).

In this chapter, general information about catalysts is introduced followed by some specific examples of transition metal complexes as catalysts, most notably compounds containing palladium, nickel, platinum and iridium. The majority of this thesis will focus on the synthesis and characterization of palladium pincer complexes.

1 In year 2001, three scientists William S. Knowles, Ryoji Noyori and K. Barry Sharpless shared the Nobel Prize in Chemistry.5 This prize was awarded for their development of chiral transition metal catalysts for stereoselective hydrogenations6-13 and oxidations.14-21 Another three scientists Yves Chauvin, Robert H. Grubbs, and Richard R. Schrock won the Nobel Prize in

Chemistry in 200522 based on their contribution to the development of the metathesis23-25 method in which carbon-carbon double bonds are broken and formed aided by transition metal catalysts.

These great scientists are exploring an important field of chemistry, catalysis by transition metal catalysts.

A catalyst is a substance used to lower the activation energy of a reaction without itself being changed at the end of the reaction. In other words, it accelerates the reaction without being consumed. Generally, catalysts only change the reaction rate and are not related to the thermodynamics of the reaction process. Using catalysts may result in a great reduction of the usage of energy, more products in a shorter time and fewer side-products/wastes/pollutants.

Transition metal catalysts are the most widely used catalysts in organic synthesis. Why are transition metal compounds good catalysts? In brief, a catalyst affects the transition state and changes the activation path; the transition metals possess different oxidation states and can facilitate the electron transfer to a substrate by undergoing formal oxidation/reduction. Those

Nobel Prize winners mentioned above have successfully developed the fields of catalytic asymmetric synthesis and metathesis using transition metal catalysts. Such new discoveries are showing enormous applications in synthesizing new drugs, biologically active compounds, and polymeric materials.

2 1.1.2 Palladacycles

Palladacycles are doubtless a very important class in palladium catalysis. A well-known example is Pd2(P(o-Tol)3)2(μ-OAc)2 (1), which is a dimeric complex and was introduced by

Hermann and Beller et al. (Chart 1.1).26,27 These types of complexes are referred to as palladacycles, palladium compounds containing at least one palladium-carbon bond and stabilized by at least one intramolecular donor atom.

R R R R' O O P Pd Pd P O O R R' R R

(R = o-Tol, R' = H) 1 Chart 1.1. Herrmann-Beller palladacycle. 26,27

Considering the binding patterns of the electron donors, palladacycles can be divided into are two classes, one with four-electron anionic donor (CY) such as Herrmann-Beller palladacycle, other with six-electron anionic donor (YCY) which is also called “pincer” and will be discussed in the next section. The CY type palladacycles usually are dimers bridged by halide or acetate.

While the metalated carbon is usually an aromatic carbon, donor atom Y could be nitrogen

(2)28, sulfur (3)29, oxygen (4)30,31, or phosphorous (5)32 (Chart 1.2). Although the intramolecular chelate ring can vary from a three-membered ring to eight-membered rings, five- and six-membered systems are the most common in palladacycles and much more stable compared to three- or four-membered palladacycles.33

3 Cl Cl Pd Pd 2 2 R1 N R1 S R2 23

Cl Cl Pd Pd 2 HN O 2 O P ArO OAr 4 5

Chart 1.2. Examples of palladacycles with different donor atoms.28-32

1.1.3 Pincer Ligands and Complexes

Palladium pincer complexes are another major type of palladacycles. The name of “pincer” comes from the coordination mode of the six-electron donor, from which two metallacycles are formed. It is the second metallacycle that provides additional stabilization for the metal-carbon bond (Pd-C bond in palladacycles) compared to the CY type of palladacycles. The first example of pincer type complexes was reported by Shaw and Moulton at late seventies.34

Pincer complexes show unusual properties and have great potential in catalytic reactions.

Therefore, these tridentate chelating systems have attracted increasing interests.1-4,33,35

4 t t P Bu2 P Bu2

M X

t t P Bu2 P Bu2 6 7

Chart 1.3. First PCP pincer complex (right) reported by Shaw et al.34

- Most of these pincer ligands are constructed having a m-xylyl backbone [2,6-(DCH2)2C6H3] , and the chelation to the metal center with the donor atoms D (such as PR2, OR, NR2 or SR) and the ipso carbon affords so-called pincer complexes (Scheme 1.1).

NMe2 PR2 SR'

R1 R1 R1

NMe2 PR2 SR' NCN PCP SCS

Metalation

chiral pocket steric constrants D

cavity for metal binding M X with tunable accessibility R1 sites for counterions or ancillary ligands D anchoring site remote electronic modulation hardness/softness metal-binding rigidity steric constranits of substituents coordination 2e donor or free Lewis base Scheme 1.1. Potential modification sites of pincer ligands and complexes.1

5 Phosphinite palladium PCP pincer complexes (Chart 1.4, compound 836,37) are similar to the xylyl-based pincer system with oxygen atom instead of methylene group in the chelating ring.

More importantly these phosphinite PCP pincer complexes can show better catalytic activity than the phosphine analogues. Installation of iridium into either phosphine or phosphinite PCP pincer framework (Chart 1.4, compound 938,39) has showed excellent application in homogeneous alkane dehydrogenations.

iPr tBu

O P iPr O P tBu H Pd Cl Ir H O P iPr O P tBu

iPr tBu 89

Chart 1.4. Phosphinite-palladium and iridium pincer complexes.36-39

Besides these most common symmetrical five-membered ring m-xylyl based pincer systems, some examples of unsymmetrical pincer complexes (Chart 1.5) are also reported, such as CNN

(10), SCN (11) and NCP (12) pincer complexes,40-42 as well as carbene type pincer complexes introduced by Crabtree et al (Chart 1.6).43-45

6 Me Me N N O iPr Cl P iPr N Pd Cl Pd Cl Pd Cl Cl S N Me Me Me

10 11 12

Chart 1.5. Unsymmetrical pincer complexes.40-42

Br Br

N N N N N N N N Pd Pd Pd N N N N N N Br Br Br

13 14 15

Chart 1.6. Tridentate carbene CNC, CCC pincer palladium complexes.43-45

All the pincer complexes mentioned above have been used as homogeneous catalysts. Many researchers are also focusing on developing a catalytic system combining the advantages of homogeneous and heterogeneous systems. The key step to this approach is to immobilize these homogeneous catalysts (pincer complexes) to a heterogeneous supports. One of the methods to afford polymer supported pincer complex is to use functionalized metallic pincer complex as monomer substrates for polymerization (Scheme 1.2).1 The catalysts could be easily recovered by filtration. In terms of filtration techniques, a spherical shaped polymer is expected to have better results than linear shaped polymer. A dendrimer supported pincer complex with such

7 desired spherical shape was then reported by van Koten et al. (Chart 1.7)46,47

NMe NMe2 2 Br CuBr HO M Br O M Br

NMe NMe2 2 O MeO (MMA)

O NMe2 Br R = COOMe O M Br M = Pd, Pt R R n NMe2

Scheme 1.2. Synthesis of polymer supported pincer complexes.1

Chart 1.7. Dendrimer supported nickel pincer complex. (from ref 1)

8 1.2 Applications of Pincer Complexes

1.2.1. Heck Reactions

Since the introduction of Hermann-Beller catalysts, many palladacycles have been proved to be high efficient and robust catalysts in Heck coupling reactions, arylation of olefins. Pincer palladium complexes are among those remarkable catalysts; even attract more interests due to the special chelating feature of pincer ligands. The first example of PCP pincer complexes catalyzed Heck reactions were reported by Milstein and coworkers.48 Three PCP pincer complexes 17-19 (Chart 1.8) showed very high turnover numbers (TONs > 100 000) and high yields in coupling olefins with arylhalides including unactivated aryl bromides (Table 1.1).

i i t P Pr2 P Pr2 P Bu2

Pd TFA Pd TFA Pd TFA

i i t P Pr2 P Pr2 P Bu2

17 18 19 Chart 1.8. Examples of efficient pincer catalysts for Heck reactions.48

Table 1.1. Catalysis results of Heck reactions by complexes 17, 18 and 19.48

O O "Pd", NaCO AX + 3 O o A O NMP, 140 C

entry ArX Catalysta time (h) TON yield(%)b 1 PhI 17 60 142,900 100 2 PhI 18 20 142,900 100 3 PhI 19 40 142,900 100 4 PhBr 18 63 132,900 93

5 4-CHO-C6H4Br 18 63 113,300 79 ArX/methylacrylate = 5/6 (mmol/mmol), a 3.5×10-5 mmol; b determined by GC

9 Bergbreiter and coworkers reported the first example of SCS pincer palladium complex (20)49 which was a robust catalyst for Heck reactions. Complex 20 catalyzed aryl iodides with different types of akenes in good yields. However, this SCS pincer complex showed little catalytic activity for aryl bromides.

SPh

AcNH Pd Cl

SPh 20 Chart 1.9. Example of SCS pincer complex.49

Finding good catalysts for Heck coupling of olefins with aryl chlorides is of great importance due the much lower cost of aryl chlorides than aryl bromides or aryl iodides.

Among those reported pincer complexes for Heck coupling reactions, phosphinite palladium pincer complex 8 has showed great catalytic reactivity for unactivated aryl chlorides.37

Table 1.2. Results of Heck reactions catalyzed by complex 8.37

i O P( Pr)2 O O "Pd", base Pd Cl 8 Ar-Cl + A O O o i dioxane, 120 C O P( Pr)2

entry ArX base time (h) yield(%) 1 PhCl CsOAc 120 >99a b 2 PhCl Cs2CO3 120 95 b 3 PhCl Na2CO3 120 87 a 4 4-MeO-C6H4Cl CsOAc 120 86 a 5 4-CHO-C6H4Cl CsOAc 120 81 Catalyst load: 0.67 mol % ; a isolated yields; b determined by GC

10 1.2.2. Suzuki-Miyaura Coupling Reactions

Palladium pincer complexes show catalytic reactivity not only for Heck reactions, many examples have been reported for their application in Suzuki-Miyaura coupling reactions.

Phosphinite palladium pincer complexes show good catalytic activity in Suzuki-Miyaura coupling reactions similar to the Heck reactions mentioned above. Bedford and coworkers reported complexes 21 and 22 as good catalysts for the coupling reactions of phenyl boronic acid with unactivated arylbromides, and also moderate yields were achieved for some activated arylchlorides (Table 1.3).50 N-heterocyclic NCN palladium pincer complexes 23 and 24 were reported by Churuca and coworkers (Chart 1.10),51 which contain two pyrazole units as donating groups to form NCN pincer complexes. These NCN pincer complexes acted as active catalysts for Suzuki-Miyaura, Heck and Sonogashira coupling reactions. Some selected results for

Suzuki-Miyaura coupling reactions were listed in Table 1.3.

R' Ph

O P Ph N R' O N R Pd Cl Pd Cl O N R' O P Ph N Ph R' 21: R = H 23: R' = H 22: R = Me 24: R' = Me

Chart 1.10. Reactive pincer catalysts for Suzuki-Miyaura coupling reactions.50,51

11 Table 1.3. Selected results of Suzuki-Miyaura coupling reactions.50,51

"Pd" catalyst R' X + B(OH)2 R' K CO 2 3

entry R’ X catalyst (mol %) yield 1 -OMe Br 21 (0.01) 61a 2 -OMe Br 21 (0.0001) 19a 3 -OMe Br 22 (0.01) 72a 4 -NO2 Cl 21 (0.01) 43a 5 -NO2 Cl 22 (0.01) 40a 6 -NO2 Cl 22 (0.1) 67a

Reaction condition: aryl halide/PhB(OH)2/base: 1:1.5:2 (mmol/mmol/mmol); Toluene 5 mL, 130 °C, 18 h. a Determined by GC. 7 -H Br 23 (0.1) 99b 8 -H Br 24 (0.1) 99b 9 -Me Br 23 (0.1) 99b 10 -Me Br 24 (0.1) 92b 11 -OMe Br 23 (0.1) 94b 12 OMe Br 24 (0.1) 93b

Reaction condition: aryl bromide/PhB(OH)2/base: 1:1.5:2 (mmol/mmol/mmol); H2O 1 mL, 100 C, 2h. b Determined by NMR spectroscopy.

12 1.2.3. Dehydrogenation Reactions

Efficient catalytic dehydrogenation of alkanes has great potential applications in transformation of alkanes to a more valuable synthetic intermediate, olefins. Soluble transition metal catalysts have shown promising results for this type of homogeneous catalytic transformations, especially after the introduction of iridium PCP pincer complexes (25, 26, Chart

1.11) by Jenson and coworkers.38,52-54 These iridium pincer complexes have shown to be active catalysts in transfer dehydrogenation reactions (Scheme 1.3). Later these catalysts were also found to be good for acceptorless hydrogenations as well.55 More thermostable anthraphos pincer complexes 27 and 28 (Chart 1.11) were reported by Haenel et al.56 which remain stable and catalytic active at 250 °C when transforming cyclododecane to trans/cis cyclododecene and hydrogen. Brookhart and coworkers have reported a phosphinite PCP iridium pincer complex

9,39 as well as its derivatives 29-34 (Chart 1.12) with modification of the para- position of the central benzene ring. Complexes 29-34 catalyzed transfer dehydrogenation of cyclooctane

(COA) to cyclooctene (COE), and showed about one order of magnitude more reactive than the benchmark catalyst 25. In addition to the proposed mechanism by Jenson (Scheme 1.4),38 mechanism of these dehydrogenations has also been studied in details, both experimentally and theoretically.57

R R

P R P R t H 25: R = Bu H 27: R = tBu Ir i 26: R = Pr Ir 28: R = iPr H H P R P R

R R Chart 1.11. Diphosphine PCP iridium pincer complexes.38,52-56

13 tBu 29: X = MeO O P tBu 30: X = Me Cl X Ir 31: X = H H 32: X = F t O P Bu 33: X = C6F5 34: X = ArF t Bu Chart 1.12. Diphosphinite PCP iridium pincer complexes.39

Iridium Pincer Catalyst + tBu + tBu

Scheme 1.3. Transfer dehydrogenation catalyzed by iridium pincer complexes.

t t P Bu2 P Bu2 H2C CHCMe3 H CMe3 H H3CHC CHR Ir Ir H H t t P Bu2 P Bu2 hydrogen transfer pathway

t CH3 slow t P Bu2 H2 P Bu2 R CH2CH2CMe3 Ir H Ir H H acceptorless t t P Bu2 pathway P Bu2

H2C=CHR H3CCH2CMe3

t t P Bu2 CH3 P Bu2 CH Ir R Ir H t t P Bu2 P Bu2

slow t t P Bu P Bu2 H CCH R isomeriation 2 3 2 C H R pathway R 2 4 Ir H Ir H H t PtBu P Bu2 2

Scheme 1.4. Proposed mechanism for catalytic alkane dehydrogenation.38

14 Most recently, Goldman, Brookhart and their coworkers introduced a new catalytic system that incorporates iridium pincer complex 31 for alkane dehydrogenation and a second catalyst for olefin metathesis.58 This combination has been demonstrated as an effective system for catalytic alkane metathesis, and complete selectivity for linear products (n-alkane) has been obtained (Scheme 1.5)

2 M 2 MH2 2 MH2 2 M olifen R R 22R R metathesis R R ++H C=CH H C-CH 2 2 3 3 Scheme 1.5. Alkane metathesis via tandem transfer dehydrogenation-olifen metathesis (M, iridium pincer complex 31).58

15 1.2.4. Kharasch Additions

Another C-C bond formating reaction is the Kharasch addition, in which a polyhalogenated alkane is added to an olefin substrate forming a 1:1 adduct (Scheme 1.6). This reaction was discovered by Kharasch in the late thirties,59,60 in which a transition metal complex was used as a radical initiator and the olefin substrate was converted to the 1:1 CCl4 adduct. After the introduction of dimethylamino NCN pincer complexes (35, 36, Chart 1.13) by van Koten and coworkers in the late 1980s, the nickel NCN pincer complex 36 was found to be a very effective

61 catalyst for the reaction of methylacrylate with CCl4. The reaction was complete in 15 min under room temperature in 90% yield.

R' H R' H + CX3Y X CCCX2Y R H R H

Scheme 1.6. Kharasch addition, X = halogen; Y = H, halogen, CF3 or other electron negative groups.

N 35: M = Pd R M X 36: M = Ni

Chart 1.13. Dimethylamino NCN pincer complexes.

The reaction mechanism was also studied by van Koten et al.61,62 The para-position substituents of the complex 36 have significant effect on it catalytic activities. While

16 electron-withdrawing groups decreased the reaction rate, the electron-donating groups expediate the reaction. Meanwhile, the greater the steric bulk at the nitrogen donor, less catalytic activity was observed. An ionic species [2,6-{C6H3(CH2NMe2)2}Ni(CH3CN)]BF4 was also studied.

However, no catalytic activity was observed. This result indicated that the dissociation of Ni-X to produce a cationic nickel species during the catalytic process may not be involved. A proposed mechanism is shown in Scheme 1.7.

CCl NiII(NCN)X 4

k-1 k1 H R'

Cl3CC C Cl H R N Cl Cl k k NiII C 3 -3 Cl X N Cl H R' III Ni (NCN)(X)(C) Cl3CC C H R

N Cl3C NiIII Cl

H R' N X k2 H R

Scheme 1.7. A proposed mechanism of Kharasch reaction catalyzed by NCN nickel pincer complex.62

17 1.2.5 Transfer Hydrogenation

van Koten and coworkers have reported NCN and PCP pincer type ruthenium complexes 37,

38 and 39 (Chart 1.14).63 These ruthenium complexes have shown high catalytic activity for the reduction of different ketones to the corresponding alcohols using iso-propanol serves as hydrogen source. The potassium hydroxide was also added to the reaction as the promoter.

The catalytic reaction results are shown in Table 1.4.

NMe2 PPh2 PPh2 PPh3 PPh3 PPh3 Ru Ru Ru Cl Cl OSO2CF3

NMe2 PPh2 PPh2

37 38 39 Chart 1.14. Ruthenium pincer complexes.63

Table 1.4. Results of transfer hydrogenation catalyzed by ruthenium pincer complexes.63

O OH "Ru" catalyst OH O + + R' R" o R' KOH, 82 C R"

conversion [%] entry substrate product catalyst (mol%) TOF [h-1] (t [h]) 1 37 (0.1) > 98 (3.3) 1100 2 O OH 38 (0.01) > 98 (1.8) 10 000

3 39 (0.01) > 98 (1.2) 27 000 4 O OH 37 (0.1) 70 (44.0) 36

5 Ph Ph 39 (0.1) 90 (0.5) 9000 6 O OH 37 (0.1) 90 (90.0) 83

7 Ph Ph Ph Ph 39 (0.1) > 98 (108.0) 100 8 O OH 37 (0.1) 90 (4.5) 1000

9 39 (0.1) 90 (1.5) 2000

18 1.2.6 Asymmetric Aldol Reactions

Introducing chiral groups to modify the methylene groups in the pincer backbone or to the donor atoms are feasible ways to make these pincer complexes chiral, and thus may afford enantioselectivity in catalytic asymmetric synthesis. Gorla et al. reported an enantiomerically pure PCP platinum pincer complex 4064 with the methylene groups being modified by chiral groups. During the aldol condensation of aldehyde and isocynoacetate, the catalytic species is obtained via chloride abstraction with silver triflate, in which a labile coordinate site at the platinum center is available for the binding of isocynoacetate. With the assistance of the base, intermediate isocyno enolate is produced, and then acts as nucleophile to attack the aldehyde.

A shorter synthetic procedure to produce stereogenic centers in the methylene carbons was reported by Longmire et al.65 A chiral PCP palladium complex 41 was produced and used as an efficient catalyst precursor in asymmetric aldol reactions. Another example of chiral pincer is complex 42,66 in which chiral centers were introduced by synthesizing chiral phosphine donating groups. The stereogenic centers are closer to the catalytically active metal center than the former examples with chiral centers anchored in the methylene groups. However, no appreciable stereoselectivity was obtained during the symmetric aldol reactions. Some catalytic results are listed in Table 1.5.

19 O tBu O PPh P PPh2 2 Ph Pt Cl Pd Cl Pd Cl Ph PPh2 PPh2 P t O Bu

O 40 41 42 Chart 1.15. Chiral PCP pincer complexes for asymmetric aldol reactions.64-66

Table 1.5. Results of asymmetric aldol reactions catalyzed by chiral pincer complexes.64-66

O O O O R R Cat./AgOTf O O + CN R H O i O N + NEt Pr2 O N THF or CH2Cl2 trans cis catalyst yield % ee entry aldehyde trans/cis (mol%) (%) trans cis

1 O 40 (1.5) 96 65 3 70/30

2 H 41 (1.0) 85 24 67 78/22 3 42 n/a < 11 ~96/4 O 4 H 40 (1.5) 94 54 8 87/13 5 41 (1.0) 73 4 53 88/12

6 O 40 (1.5) 65 15 22 90/10 H 7 41 (1.0) 84 26 71 86/14

8 O 40 (1.5) 92 18 32 75/25

9 H 41 (1.0) 91 30 70 91/9

20 1.3 Synthesis of Pincer Complexes

There are many methods to corporate pincer ligand to a transition metal center to afford

“pincer” complex. Depending on different properties of the transition metal, the electronic donating feature of the donor atoms, and the steric aspects, different strategies are used.

1.3.1. Direct Cyclometalation

Direct cyclometalation is most straightforward method to produce a pincer complex.

Actually, many examples of pincer complexes were synthesized by this method (Scheme 1.1), including the first PCP transition metal pincer complexes 7 reported by Shaw et al.34 In the case of NCN pincer complexes, the bond strength of M-N bond is relatively low compared to the

PCP analogues. The kinetically controlled product is produced when R”= H. This undesired product can be prevented by introducing a SiMe3 group instead of H in the 1- position of the central benzene ring (Scheme 1.8).67,68

NR2

PdCl2 Pd Cl + ClSiMe R = Me 3 NR R"= SiMe3 2 NR2

R" R2 N M NR2 PdCl2 or PtCl2 + HCl R = Me, Et R" R"= H M N R2 Scheme 1.8. Direct cyclometalation of NCN pincer ligand.67,68

21 1.3.2. Oxidative Addition

Since the C-H bond in the central benzene can sometime be difficult to activate by the direct cyclometalation, installation of a halogen atom (X = I, Br) in that position offers opportunity for

69 66,70 a low valent metal, such as Ni(COD)2, Pd2(dba)3 to undergo oxidative addition to the carbon halogen bond (Scheme 1.9). This method has been applied to many NC(X)N pincer ligands which did not undergo direct cyclometalation.70-72

E E n M n+2 X M X

E E Scheme 1.9. Oxidative addition of pincer ligand by low valent metal.1

1.3.3. Transmetalation and Transcyclometalation

Direct cyclometalation and oxidative addition are now widely used in synthesizing many pincer type complexes. Other methods such as transmetalation (Scheme 1.10)66,70 and transcyclometalation (TCM, Scheme 1.11)73-76 have also been investigated. In the process of transmetalation, the lithiation of the ligands may result in not only the aryllithium but also the undesired benzyllithium complex. As a novel methodology for metal insertion, transcyclometalation has successfully applied to the metalation of polyfuntional cartwheel ligands, which could not be cyclometalated by the above methods.

22 D D D lithiation transmetalation X Li M X

D D D Scheme 1.10. Transmetalation of aryllithium complex to transition metal pincer complex.1,66,70

D D' D D' TCM M + H H + M

D D' D D' Scheme 1.11. Transcyclometalation method to produce desired pincer complexes.73-76

23 1.4. Proposed Work

As described in section 1.2, many pincer systems have been investigated. These special metallacycles have shown great applications in numbers of catalytic reactions, and many are still under investigation. We mentioned catalytic asymmetric synthesis in section 1.2.6, however, there are not many chiral complexes that have been synthesized, and there has been no great breakthrough in using chiral pincer complexes in of asymmetric catalysis. It is the strong bond strength of the M-C bond stabilized by two metallacycles that gives pincer complexes special properties. In addition to the massive research on palladium pincer complexes, many other transition metal pincer complexes have been studied as well, such nickel, platinum, ruthenium, iridium, and more.1,2,4

In terms of chirality of pincer complexes, many attempts have been made to generate stereogenic centers in order to increase the stereoselectivity in asymmetric synthesis, including modification of benzylic carbon to a chiral center, or using a pincer ligand with chiral donating atoms.65,66,77,78 Based on the results that have been reported, there is still a lot of room for developing new pincer complexes with high stereoselectivity.

Most of the known pincer complexes are constructed with a m-xylyl backbone. Even though these two chelating rings puckering in either side of the central benzene ring, the fast interconversion of its two atropisomers (Scheme 1.12, a and a’) describes this pincer structure as nearly flat nature.4 A twist angle Φ is defined in Scheme 1.12. Examples of m-xylyl based PCP pincer complexes 43,64 4479 and 4580 show twist angles range from 8-20°, while NCN pincer complexes 46, 4781 and 4882 show twist angles range from 9-13° (Chart 1.16).

24 D D

M M D aa'D Φ

Scheme 1.12. Interconversion of two atropisomers a and a’.

PR2 NMe2

Pd Cl R' Pd Cl

PR2 NMe2 o o 43 R = Ph, Φ = 19.5 46 R' = NMe2, Φ = 12.8 o o 44 R = Cy, Φ = 7.6 47 R' = COMe, Φ = 11.2 t o o 45 R = Bu, Φ = 11.0 48 R' = NO2, Φ = 8.7 Chart 1.16. Examples of m-xylyl based pincer complexes with twist angles listed.64,79-82

The main goal is to develop a new type of pincer complexes containing a 3-D framework, rather than the traditional m-xylyl backbone. The 3-D framework chosen here is based on the pass success on employing m-terphenyl scaffolds to stabilize low coordinate phosphorus atoms.83-85

The structure of the target molecule is shown in Chart 1.17. The key feature of this newly designed molecule is its C2 symmetric environment which makes it a chiral structure.

Numerous examples of chiral ligands containing C2 symmetric environment, such as BINAP

(Chart 1.18), have already shown great application in catalytic asymmetric synthesis.86,87

25 R R R R

P P

Pd Pd

X X P P

R R R R

Chart 1.17. Target molecules containing C2 symmetric environment.

PPh2 PPh2

Chart 1.18. BINAP

Since the most straightforward route to generate pincer complexes is direct cyclometalation

(Scheme 1.13, a), the first try was obviously to synthesize the terphenyl diphosphine ligands

(Scheme 1.13, b). As mentioned at section 1.3.1, PCP pincer ligands are more readily to undergo direct cyclometalation than NCN pincer ligands.

26 D D D D

D D M D M D

D D M D M D (a) (b)

Scheme 1.13. Construction of a new pincer complex bearing m-terphenyl scaffold.88

However, the initial effort to construct this 3-D pincer complex with m-terphenyl scaffold was not successful, although the m-terphenyl PCP ligands were obtained in good yields. Instead of the expected palladium complex, a trans-spanning diphosphine palladium was obtained (Scheme

1.14).88,89

NBS LiPPh2

Br Br

PdCl2(NCPh)2 Cl P Pd P PPh PPh Ph Ph 2 2 Ph Cl Ph

Scheme 1.14. Synthetic procedure for trans-spanning diphosphine palladium complex.88

27 The reasons for the unsuccessful metalation are not certain. Since the C-H bond in the central benzene ring may not be easy to activate in this case, the next logical route would be to synthesize new diphosphine pincer ligands with a halogen atom (X = Br, I) installed in the central benzene ring. Thus the C-X bond should be susceptible to oxidative addition by low valent metal centers, and it is more likely to form the targeted pincer complex (Scheme 1.15).

Ph Ph R2P P X Pd (dba) 2 3 M

PR2 or Ni(COD)2 P X Ph Ph Scheme 1.15. Proposed synthetic method to afford pincer complex by oxidative addition.

Details about the diphosphine pincer ligand synthesis and characterization will be discussed in

Chapter 2. Since these diphosphine pincer ligands have been successfully employed in the architecture of palladium complexes (see Chapter 3), other types of donor groups are also investigated and shown in the following chapters, including NCN diimine pincer complexes and

NCN dimethylamino pincer complexes as well. In terms of separation of enantiomers of these chiral pincer complexes, initial efforts on fractional crystallization of diastereomers of PCP diphosphine pincer complexes with halogen atom substituted with chiral amine, however, were not successful. Nevertheless, an alternative route has been introduced, and two optically pure

NCN diimine pincer complexes have been isolated (Chapter 6). Structures of these new pincer complexes have been characterized by X-ray crystallography, and NMR spectroscopy including

2-D multinuclear NMR spectroscopy. The structural rigidity of these complexes has been demonstrated.

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34 Chapter 2. Synthesis and Characterization of PCP Pincer Ligands Based on m-Terphenyl

Scaffolds

2.1 Introduction

Pincer ligands1-6 are an exciting class of ligands that are receiving increasing attention for applications ranging from catalysis, sensors, to materials science.7-13 The core backbones in most of the pincer systems (m-xylyl based) are made up of two five-member rings, which process a nearly planar framework (Scheme 2.1a). Among these pincer systems diphosphine pincer

D D n n MX2 M X (n=1,2...) (a)

D n n D

Br PR2

(b)

Br PR2

Scheme 2.1 General synthetic routes for pincer ligands and complexes. (D = PR2, NR2, SR, etc.) ligands were well studied (Scheme 2.1b). In order to tune the catalytic properties of those pincer complexes, researchers are focusing on the design of ligands. To integrate chirality into

BH3 R P Ph PPh2 R

R Ph P PPh2 BH3 R 2.1 2.2

Chart 2.1. Examples of chiral PCP pincer ligands.14,15

35 the pincer backbone is of great interest. Either introducing chiral donor groups14 (Chart 2.1,

2.1), or modifying the methylene groups15 (Chart 2.1, 2.2) are feasible routes to make them

‘chiral’. Another possible way is to modify the flat nature of these five-membered ring structures. It is well known that many chiral ligands, such as BINAP (2.3) (Chart 2.2),16,17 containing C2 symmetric environment show excellent results in asymmetric catalytic synthesis.

PPh2 PPh2

2.3

Chart 2.2. BINAP

Our strategy is to use a m-terphenyl scaffold as the pincer backbone. Our initial efforts to synthesize this new kind of diphosphine ligand 2.6 (Chart 2.3) were followed by the reaction with Pd(II) sources, such as Pd(NCPh)2Cl2. Unfortunately, only trans-spanning diphosphine palladium pincer complexes 2.7 were obtained instead (Scheme 2.2).18,19 In this chapter, three other similar pincer ligands are introduced, all of which contain a bromine atom in the central benzene ring. Based on this idea, a palladium(0) atom can oxidatively add the aryl C-Br bond and form a stable C-Pd bond. Detailed synthetic procedure and results are included in this chapter. The synthesis of pincer complexes and the data analysis will be described specifically in the next chapter. Parts of this chapter have been communicated; see reference (20).

36 R2P

PR2

C2 Chart 2.3. Diphosphine pincer ligand constructed with m-terphenyl.

NBS LiPPh2

Br Br 2.4 2.5

PdCl2(NCPh)2 Cl P Pd P PPh PPh Ph Ph 2 2 Ph Cl Ph 2.6 2.7

Scheme 2.2. Synthesis of trans-spanning diphosphine ligand and palladium complex.18

2.2 Results and Discussion

It was discovered that the shorter synthesis used to prepare non-halogenated analogues

[2,6-(2-R2PCH2C6H4)2C6H4] (2.6) had to be modified. Specifically, the key intermediate

[2,6-(2-BrCH2C6H4)2C6H3Br] (2.12) could not be cleanly prepared by direct bis-monobromination of the tolyl groups of 2.8, due to formation of difficult-to-separate mixtures of mono-, bis-, tri-, and tetra-halogenated products.8 Instead, synthesis of the readily purified 2.9 allowed facile synthesis of 2.10 and 2.11, which could then be used to access 2.12

37 from 2.8 in 56% overall yield (Scheme 2.3).

O CHBr2 NBS, Δ Ag(NO3)2/ NaOAc Br Br Br Δ CHBr2 O 2.8 2.9 2.10

Br CH2OH NaBH4 PBr3 2.10 Br Br CH2OH Br 2.11 2.12

Scheme 2.3. Synthesis of ligand precursors.

Compounds 2.8-2.12 were characterized by 1H NMR and 13C NMR spectroscopy. All of these materials show two sets of resonances in NMR spectra corresponding to the syn- and anti- conformations which do not exchange within the NMR time scale at room temperature. Only anti- isomers are shown in the above scheme. Attempts to separate and syn- and anti- conformation of these precursors were carried out for compound 2.9 (Figure 2.1). These isomers remain their confirmation during the isolation and characterization process.

Figure 2.1. 1H NMR spectra of 2.9. Top: mixture of two isomers; bottom: a sample enriched with one of the isolated isomers.

Diphosphine 2.13 was produced in good yield by reacting 2.12 and PPh2Li in THF under nitrogen atmosphere (Scheme 2.4). This diphosphine ligand is air-sensitive. Analytically pure phosphine oxide of 2.13 was thus produced by bubbling O2 into THF solution followed by preparation TLC. Diphosphine ligands 2.14 and 2.15 were synthesized by reacting with dialkyl phosphine followed by adding a base, NaOAc, to neutralize the acidic adducts. The acidic adducts of 2.15•(HBr)2 can be isolated in good yield. However, no pure 2.14•(HBr)2 was isolated.

39 PR2

Br R = Ph: LiPPh2 Br t Br R = Cy or Bu: PR 1. HPR2, acetone, reflux 2 2.13 2.14 2.15 Br 2. NaOAc, THF R = Ph Cy tBu 92% 62% 72% 2.12 Scheme 2.4. Synthesis of diphosphine ligands 2.13-2.15.

Each diphosphine ligand is readily characterized by standard 1H and 31P NMR spectroscopy.

Diphosphine 2.13 shows two 31P NMR signals in its spectrum, consistent with the presence of two isomers (syn- and anti-) in about a 50:50 ratio. 31P NMR spectra of diphosphines 2.14 and

2.15 indicate a much smaller ratio (ca. 10% or less) of a second isomer. The increased steric bulk of the benzyl groups in 2.14 and 2.15 presumably disfavors the syn isomers, as the precursors 2.8-2.12 all show syn- and anti-isomers in about a 50:50 ratio (by 1H NMR spectroscopy). The chemical shifts in 31P NMR for 2.13-2.15 are -10.2, 1.3, 30.4 ppm, respectively. Later on, it was discovered that this ratio may change depending on the solvent and the time being dissolved in. X-ray quality crystals of 2.13 and 2.15 were grown from concentrated diethyl ether solution at low temperature (-35 ºC). A crystal structure of 2.13 indicates a syn- conformation (Figure 2.2), while crystal structure of 2.15 shows an anti- conformation (Figure 2.3).

Figure 2.2. An ORTEP drawing (40% probability thermal ellipsoids) of 2.13 with atom labeling scheme. Hydrogen atoms have been omitted for clarity.

Figure 2.3. An ORTEP drawing (40% probability thermal ellipsoids) of 2.15 with atom labeling scheme. Hydrogen atoms have been omitted for clarity.

41 Table 2.1. Selected bond lengths (Å) and angles (°) for 2.13 and 2.15.

2.13 C1-Br1 1.901(1) P1-C19-C8 113.04(9) P1-C19 1.855(1) C19-P1-C21 99.95(6) P1-C21 1.843(1) C19-P1-C27 99.94(6) P1-C27 1.838(1) C21-P1-C27 99.89(6) P2-C20 1.868(1) P2-C20-C14 111.6(1) P1-C33 1.837(2) C20-P2-C33 100.24(6) P1-C39 1.828(2) C20-P2-C39 102.37(7) C33-P2-C39 101.35(7) C8-C7-C6-C1 64.5 C14-C13-C2-C3 74.3 2.15 C1-Br1 1.910(2) P1-C19-C8 116.4(1) P1-C19 1.862(2) C19-P1-C21 98.42(8) P1-C21 1.891(2) C19-P1-C25 102.78(9) P1-C25 1.893(2) C21-P1-C25 109.53(9) P2-C20 1.860(2) P2-C20-C14 117.0(1) P2-C29 1.885(2 C20-P2-C29 102.57(9) P2-C33 1.889(2) C20-P2-C33 99.37(9) C29-P2-C33 110.32(8) C8-C7-C6-C1 72.2 C14-C13-C2-C1 82.3

Comparing the torsion angles of the two side phenyl rings in the m-terphenyl scaffold, they appear different in both ligands 2.13 and 2.15. For 2.13 the torsion angles of C8-C7-C6-C1 and

C14-C13-C2-C3 are 64.5º and 74.2º, and the torsion angles of C8-C7-C6-C1 and C14-C13-C2-C1 in

2.15 are 72.2º and 82.3º. The nature of interconversion of syn- and anti- conformations of these diphosphine ligands makes it possible to convert to a pure form of metal complexes, either trans-spanning complexes or pincer type complexes.

42 2.3 Conclusion

A set of diphosphine pincer ligands constructed with m-terphenyl scaffolds have been synthesized. The key difference of these diphosphine ligands compared to the previous reported diphosphine ligands bearing m-terphenyl is the introduction of a halogen atom (bromine for the above examples) into the central benzene ring.

NMR spectroscopic studies of these diphosphine ligands revealed that there are two stable conformations, syn- and anti-, of the ligands on NMR time scale, while crystal structure analysis of two of these diphosphines showed that it is possible to isolate a pure conformation from slow recrystallization in certain solvents.

43 2.4 Experimental

General Procedures and Materials

Experiments were carried out using standard Schlenk techniques or in a glove box under nitrogen. Certified A.C.S.-grade solvents (diethyl ether, CCl4, CH2Cl2, ethanol, methanol, hexanes, ethyl acetate), anhydrous acetone from Fisher were used as received. Anhydrous solvents (THF, benzene) were distilled from Na/benzophenone prior to use. The NMR spectroscopic measurements were recorded on Varian Inova 400 or 600 MHz spectrometers.

Chemical shifts given in ppm were referenced to residual solvent signals (1H, 13C NMR) or

31 external 85% H3PO4 as reference ( P NMR). Elemental analyses were performed by

Quantitative Technologies, Inc. NJ. Routes to compounds 2.0821 and 2.09-2.1222 were adapted from the literature.

2,6-(2-CH3C6H4)2-1-BrC6H3 (2.08)

To a solution of 2,6-dichlorophenyl-lithium [prepared by stirring 2, 6-dichlorobenzene (10.3 g,

70.1 mmol) and nBuLi (30 mL, 2.5 M in hexanes) in 150 mL anhydrous THF at -78 oC for 1 h], was added dropwise a solution of (2-methylphenyl) magnesium bromide [prepared from

2-bromotoluene (29.4 g, 172 mmol) and magnesium (8.30 g, 342 mmol) in 150 mL anhydrous

THF under room temperature for 1 h]. The reaction mixture was stirred at -78 oC for 1 h, then warmed to room temperature and heated to reflux under nitrogen overnight. The reaction mixture was then cooled to room temperature, and bromine (20 g, 125 mmol) was slowly added.

The resulting solution was stirred for an additional 2 h. Diethyl ether (100 mL) was added, and excess bromine was quenched with 5% NaSO3 (aq) (3 × 100 mL). The organic layer was separated and dried with anhydrous MgSO4. After removal of the ether under vacuum the

44 material was washed with n-pentane to afford 13.2 g of 2.08 as a fine white powder (56.0 %).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H NMR

13 (CDCl3, 400 MHz): δ 2.12, 2.13, 7.15-7.20 (m, 4H), 7.22-7.31 (m, 6H), 7.34-7.40 (m, 1H). C

1 { H} NMR (CDCl3, 100 MHz): δ 20.0, 20.1, 125.1, 125.4, 125.7, 125.8, 127.1, 127.2, 128.07,

128.09, 129.3, 129.5, 129.8, 130.0, 130.1, 136.2, 136.3, 142.0, 143.6, 143.7. Elemental analysis calcd for C20H17Br (337.26): C, 71.23; H, 5.08. Found: C, 70.96; H, 4.91.

2,6-(2-CHBr2C6H4)2-1-BrC6H3 (2.9)

To a solution of 2.9 (6.00 g, 17.8 mmol) in 200 mL CCl4, N-bromosuccinimide (7.40 g, 41.6 mmol) and benzoyl peroxide (50 mg) were added. The solution was heated to reflux for 6 h, and another portion of N-bromosuccinimide (7.60 g, 42.7 mmol) and benzoyl peroxide (50 mg) were added. After an additional 18 h reflux, the mixture was cooled to RT, and the succinimide was removed by filtration; the filtrate was washed with 5% NaSO3 (aq) (3 × 100 mL) and dried with anhydrous MgSO4. The solvent was evaporated and the resulting solid was washed with n-pentane to yield 10.7 g (92.0%) of 2.9 as white solid.

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H NMR

(CDCl3, 400 MHz): δ 6.41(s, CHBr2), 6.48 (s, CHBr2) 7.15, 7.19, 7.37-7.44 (m, 4H), 7.50-7.58

13 1 (m, 3H), 8.09, 8.11 (m, 2H). C { H} NMR (CDCl3, 100 MHz): δ 38.8, 38.9 (CHBr2 of syn- or anti-), 124.9, 125.5 (Ar(C)-Br, syn- or anti-), 127.6, 127.7, 129.4, 129.8, 130.01, 130.05, 130.6,

130.8, 136.8, 137.0, 139.6, 139.7, 141.0. Elemental analysis calcd for C20H13Br5 (652.84): C,

36.80; H, 2.01. Found: C, 36.61; H, 1.71.

2,6-(2-CH(O)C6H4)2-1-BrC6H3 (2.10)

45 A mixture of 2.09 (20.00 g, 20.64 mmol), AgNO3 (21.36 g, 125.7 mmol) and NaOAc (11.33g,

138.1 mmol) in a solvent mixture of EtOH (500 mL) and THF (100 mL) was heated to reflux for

16 h. After the removal of the solid by filtration the solvent was evaporated. The resulting solid was dissolved in CH2Cl2 (300 mL) and 10% hydrochloric acid (10 mL) was added. This reaction mixture was stirred at room temperature for 6 h, then washed with water (3 × 100 mL) and the organic layer was dried with anhydrous MgSO4. The solvent was evaporated from the organic layer, and the resulting material was washed with diethyl ether and dried to yield 9.70 g

2.10 as a white solid (86.7%).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 9.90, 9.88 (s, CHO- of syn- or anti-), 8.02-8.05 (m, 2H), 7.66-7.72

13 1 (m, 2H), 7.55-7.59 (m, 2H), 7.49-7.53 (m, 1H), 7.35-7.41 (m, 4H). C { H} NMR (CDCl3,

100 MHz): δ 191.3, 191.6 (CHO- of syn- or anti-), 125.3 (Ar(C)-Br), 144.6, 144.4, 140.4, 140.3,

134.1, 133.89, 133.92, 133.7, 131.4, 131.1, 131.2, 130.9, 128.93, 128.90, 128.5, 127.9, 127.4,

127.3. Elemental analysis calcd for C20H13O2Br (365.23): C, 65.77; H, 3.59. Found: C, 65.66;

H, 3.32.

2,6-(2-CH2(OH)C6H4)2-1-BrC6H3 (2.11)

To a slurry of NaBH4 (1.20 g, 24.6 mmol) in THF (150 mL), a solution of 2.10 (9.00 g, 24.6 mmol) in MeOH (100 mL)/THF (50 mL) mixture was added slowly. After stirring overnight ,

15% hydrochloric acid (10 mL) was added. The mixture was stirred for another 1 h. After removal of the solvent, diethyl ether (200 mL) was added, and then the solution was washed with water (100 mL × 3). The organic layer was separated and dried with anhydrous MgSO4, and then evaporated to yield 8.10 g 2.11 as a white solid (89.2%).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H

46 NMR (CDCl3, 400 MHz): δ 1.59, 1.72 (broad, OH, of syn- or anti-), 4.45, 4.48, 4.52, 4.56

(-CH2-, of syn- and anti-), 7.22-7.24 (m, 2H), 7.27, 7.29, 7.37-7.48 (m, 5H), 7.56-7.61 (m, 2H).

13 1 C { H} NMR (CDCl3, 100 MHz): δ 63.3, 63.4 (-CH2-, of syn- or anti-), 124.9, 125.3 (Ar(C)Br),

127.2, 127.3, 127.69, 127.74, 128.0, 128.1, 128.6, 128.7, 129.6, 129.9, 130.2, 130.4, 138.6, 140.5,

140.7, 142.4. Elemental analysis calcd for C20H17O2Br (369.26): C, 65.05; H, 4.64. Found: C,

65.05; H, 4.52.

2,6-(2-CH2BrC6H4)2-1-BrC6H3 (2.12)

To a benzene (150 mL) solution of 2.11 (7.40 g, 20.0 mmol) containing 0.1 mL pyridine, PBr3

(4.95 g, 18.3 mmol, in 10 mL benzene) was added slowly. The mixture was stirred for 16 h, and then washed with water (3 × 100 mL) and 5% NaHCO3 (aq) (2 × 100 mL). The organic layer was collected and dried with anhydrous MgSO4. After removal of the solvent, the resulting compound was recrystallized from n-pentane to yield 7.83g 2.12 as a white solid (78.9%).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H NMR

(CDCl3, 400 MHz): δ 4.23-4.31 (m, 2H, CH2Br), 4.44-4.47 (m, 2H, CH2Br), 7.23-7.25 (m, 2H),

13 1 7.36-7.44 (m, 6H), 7.47-7.51(m, 1H), 7.53-7.56 (m, 2H). C { H} NMR (CDCl3, 100 MHz): δ

31.8, 31.9 (CH2Br, of syn- or anti-), 127.08, 127.11 (Ar(C)-Br, of syn- or anti-), 128.5, 128.6,

128.7, 128.87, 128.89, 130.4, 130.58, 130.62, 130.73, 130.82, 135.6, 135.7, 141.58, 141.66,

141.68. Elemental analysis calcd for C20H15Br3 (495.05): C, 48.52; H, 3.05. Found: C, 48.67; H,

2.83.

2,6-(2-CH2PPh2C6H4)2-1-BrC6H3 (2.13)

Freshly cut Li (0.5 g, 71 mmol) was added to a solution of diphenylchlorophosphine (2.00 g,

9.06 mmol) in anhydrous THF (100 mL). The mixture was stirred for 4 h at room temperature.

47 The excess Li metal was removed, and the resulting dark red solution was cooled to -78 oC. To the chilled solution was added a solution of 2.12 (2.00 g, 4.04 mmol) in anhydrous THF (40 mL).

The reaction mixture was warmed to room temperature and stirred for an additional 16 h.

Solvent was removed in vacuo and the remaining solid was dissolved in 50 mL diethyl ether. The undissolved solid was removed by filtration. Removal of the solvent in the filtrate yielded 2.62 g 2.13 as white solid (91.9%).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 3.14-3.20 (m, 2H, -CH2-), 3.23-3.38 (m, 2H, -CH2-), 6.79 (d, JHH =

31 8 Hz, 1H), 6.94-7.35 (m, 30H). P NMR (CDCl3, 162 MHz): δ -10.3, -10.2 (syn- or anti-).

An air-stable derivative [2,6-(2-CH2P(=O)Ph2C6H4)2-1-BrC6H3] for analysis was produced by dissolving a sample of 2.13 in THF and bubbling dioxygen through the solution, followed by evaporation. Elemental analysis calcd for [(2.13)(O)2], C44H35BrP2O2 (737.61): C, 71.65; H,

4.78. Found: C, 70.72; H, 5.16.

2,6-(2-CH2PCy2C6H4)2-1-BrC6H3 (2.14)

To a mixture of 2.12 (1.06 g, 2.14 mmol) and dicyclohexylphosphine (0.95 g, 4.8 mmol), 20 mL anhydrous acetone was added, and the resultant mixture was heated to reflux overnight under nitrogen. After cooling to room temperature, the solvent was removed in vacuo. The remaining material was dissolved in 50 mL of anhydrous THF, and sodium acetate (0.70 g, 8.5 mmol) was added. The mixture was stirred overnight. Excess sodium acetate was then removed by filtration and then the solvent was removed in vacuo. The remaining waxy compound was washed with small amount of hexanes, and dried in vacuo to yield 2.14 as a white fine powder (0.97 g, 62 %).

(Chemical shifts of two isomers are reported without further assigning to syn- or anti-) 1H NMR

(C6D6, 400 MHz): δ 0.90-1.90 (m, 42H, Cyclohexyl), 2.87 (m, 2H, P-Cy(H)), 2.83 (m, 2H,

48 -CH2-), 2.98 (d, JHH = 15 Hz, 2H, -CH2-), 7.07-7.25 (m, 8H), 7.36 (m, 1H), 7.87 (d, JHH = 8 Hz,

31 2H). P NMR (CDCl3, 162 MHz): δ 1.3.

t [2,6-(2-CH2P Bu2C6H4)2-1-BrC6H3](HBr)2 (2.15’)

A solution of 2.12 (1.50 g, 3.03 mmol) in anhydrous acetone (20 mL) was added to 1.00 g

(6.84 mmol) of di-t-butylphosphine, and the resultant mixture was heated to reflux overnight under nitrogen. After cooling to room temperature, 2.35 g 2.15’ as white solid compound

(98.5%) was obtained upon removal of the solvent.

1 H NMR (CD2Cl2, 400 MHz): δ 1.33 (d, JHH = 16 Hz, 18H, -C(CH3)3), δ 1.48 (d, JHH = 16 Hz,

18H, -C(CH3)3), 3.55 (m, 2H, -CH2-), 3.82 (m, 2H, -CH2-), 7.18 (d, JHH = 7 Hz, 2H), 7.47 (t, JHH

= 7 Hz, 2H), 7.53 (m, 2H), 7.73 (d, JHH = 8 Hz, 2H), 7.89 (m, 1 H), 8.01 (d, JHH = 8 Hz, 2H),

13 1 8.54 (doublet of virtual triplets, JPH = 486 Hz, 2H). C { H} NMR (CD2Cl2, 100 MHz): δ 20.1

(d, JPC = 37 Hz, -CH2-), 27.7 (s, -C(CH3)3), 27.9 (s, -C(CH3)3), 33.6 (d, JPC = 32 Hz, -C(CH3)3),

33.9 (d, JPC = 33 Hz, -C(CH3)3), 124.8, 128.7 (d, JPC = 8 Hz), 128.9 (d, JPC = 2 Hz), 129.7, 130.5,

31 131.0, 131.9 (d, JPC = 5 Hz), 133.0, 141.2 (d, JPC = 5 Hz), 141.7. P NMR (CD2Cl2, 162 MHz):

δ 32.3 (d, JPH = 480 Hz). Elemental analysis calcd for C36H53Br3P2 (787.48): C, 54.91; H, 6.78.

Found: C, 54.64; H, 6.81.

t 2,6-(2-CH2P Bu2C6H4)2-1-BrC6H3 (2.15)

To a solution of 2.15’ (1.00 g, 1.27 mmol) in THF (50 mL), sodium acetate (0.40 g, 4.9 mmol) was added and the mixture was stirred for overnight at room temperature. The excess sodium acetate was removed by filtration. After removal of the solvent, the remaining waxy material was washed by small amount of hexanes, and 0.58 g 2.15 as white fine powder compound was obtained after drying (73 %).

49 1 H NMR (CDCl3, 400 MHz): δ 0.94 (d, JHH = 11 Hz, 18H, -C(CH3)3, anti-), δ 1.07 (d, JHH = 11

Hz, 18H, -C(CH3)3, anti-), [Note: due to some overlapping signals for anti- and syn- isomersm anti- : syn- = 10 : 1; the following spectroscopy data of only the major (the presumed anti- form) are reported. Signals at δ 1.00 (d, JHH = 11 Hz, -C(CH3)3, syn-), 1.12 (d, JHH = 11 Hz, -C(CH3)3, syn-) can be clearly seen, however]. 2.67 (m, 2H, -CH2-), 2.80 (m, 2 H, -CH2-), 7.09 (d, JHH =

7 Hz, 2H), 7.22 (t, JHH = 7 Hz, 2H), 7.26-7.34 (m, 4H), 7.41 (m, 1H), 7.73 (d, JHH = 8 Hz, 2H).

13 1 C { H} NMR (CDCl3, 100 MHz): δ 25.9 (d, JPC = 24 Hz, -CH2-), 29.8 (d, JPC = 13 Hz,

-C(CH3)3), 30.0 (d JPC = 13 Hz, -C(CH3)3), 31.8 (d, JPC = 16 Hz, -C(CH3)3), 32.0 (d, JPC = 17 Hz,

-C(CH3)3), 125.4 (d, JPC = 2 Hz ), 126.6 (s), 127.8 (s), 129.8 (s), 130.6 (s), 130.7 (s), 131.1 (s),

31 139.5 (d, JPC = 12 Hz), 141.8 (d, JPC = 4 Hz), 143.2 (s). P NMR (CDCl3, 162 MHz): δ 30.4

(s), 32.4 (s), (anti- : syn- ~ 10:1).

NMR spectra

1 Figure 2.4. H NMR spectrum of 2.8 (CDCl3, 400 MHz).

13 Figure 2.5. C NMR spectrum of 2.8 (CDCl3, 100 MHz).

1 Figure 2.6. H NMR spectrum of 2.9 (CDCl3, 400 MHz).

13 Figure 2.7. C NMR spectrum of 2.09 (CDCl3, 100 MHz).

1 Figure 2.8. H NMR spectrum of 2.10 (CDCl3, 400 MHz).

13 Figure 2.9. C NMR spectrum of 2.10 (CDCl3, 100 MHz).

1 Figure 2.10. H NMR spectrum of 2.11 (CDCl3, 400 MHz).

13 Figure 2.11. C NMR spectrum of 2.11 (CDCl3, 100 MHz).

1 Figure 2.12. H NMR spectrum of 2.12 (CDCl3, 400 MHz).

13 Figure 2.13. C NMR spectrum of 2.12 (CDCl3, 100 MHz).

31 Figure 2.14. P NMR spectrum of 2.13 (CDCl3, 162 MHz).

1 Figure 2.15. H NMR spectrum of 2.13 (CDCl3, 400 MHz).

31 Figure 2.16. P NMR spectrum of 2.14 (CDCl3, 162 MHz).

1 Figure 2.17. H NMR spectrum of 2.14 (CDCl3, 400 MHz).

31 Figure 2.18. P NMR spectrum of 2.15’ (CDCl3, 162 MHz).

1 Figure 2.19. H NMR spectrum of 2.15’ (CDCl3, 400 MHz).

13 Figure 2.20. C NMR spectrum of 2.15’ (CDCl3, 100 MHz).

31 Figure 2.21. P NMR spectrum of 2.15 (C6D6, 162 MHz).

1 Figure 2.22. H NMR spectrum of 2.15 (C6D6, 400 MHz).

59 2.5 Works Cited

(1) Moulton, C. J.; Shaw, B. L. J. Chem. Soc. Dalton Trans. 1976, 1020.

(2) Rietveld, M. H. P.; Grove, D. M.; vanKoten, G. New J. Chem. 1997, 21, 751.

(3) Albrecht, M.; van Koten, G. Angew. Chem. Int. Ed. 2001, 40, 3750.

(4) van der Boom, M. E.; Milstein, D. Chem. Rev. 2003, 103, 1759.

(5) Crabtree, R. H. Pure Appl. Chem. 2003, 75, 435.

(6) Slagt, M. Q.; van Zwieten, D. A. P.; Moerkerk, A.; Gebbink, R.; van Koten, G. Coord. Chem.

Rev. 2004, 248, 2275.

(7) Ohff, M.; Ohff, A.; van der Boom, M. E.; Milstein, D. J. Am. Chem. Soc. 1997, 119, 11687.

(8) van der Boom, M. E.; Liou, S. Y.; Ben-David, Y.; Shimon, L. J. W.; Milstein, D. J. Am. Chem.

Soc. 1998, 120, 6531.

(9) Jensen, C. M. Chem. Commun. 1999, 2443.

(10) Sundermann, A.; Uzan, O.; Milstein, D.; Martin, J. M. L. J. Am. Chem. Soc. 2000, 122,

7095.

(11) Morales-Morales, D.; Redon, R.; Yung, C.; Jensen, C. M. Chem. Commun. 2000, 1619.

(12) Zhu, K. M.; Achord, P. D.; Zhang, X. W.; Krogh-Jespersen, K.; Goldman, A. S. J. Am. Chem.

Soc. 2004, 126, 13044.

(13) van Koten, G. Pure Appl. Chem. 1989, 61, 1681.

(14) Williams, B. S.; Dani, P.; Lutz, M.; Spek, A. L.; van Koten, G. Helv. Chim. Acta 2001, 84,

3519.

(15) Longmire, J. M.; Zhang, X. M.; Shang, M. Y. Organometallics 1998, 17, 4374.

(16) Miyashita, A.; Yasuda, A.; Takaya, H.; Toriumi, K.; Ito, T.; Souchi, T.; Noyori, R. J. Am.

Chem. Soc. 1980, 102, 7932.

60 (17) Berthod, M.; Mignani, G.; Woodward, G.; Lemaire, M. Chem. Rev. 2005, 105, 1801.

(18) Smith, R. C.; Protasiewicz, J. D. Organometallics 2004, 23, 4215.

(19) Smith, R. C.; Bodner, C. R.; Earl, M. J.; Sears, N. C.; Hill, N. E.; Bishop, L. M.; Sizemore,

N.; Hehemann, D. T.; Bohn, J. J.; Protasiewicz, J. D. J. Organomet. Chem. 2005, 690, 477.

(20) Ma, L.; Woloszynek, R. A.; Chen, W.; Ren, T.; Protasiewicz, J. D. Organometallics 2006, 25,

3301.

(21) Saednya, A.; Hart, H. Synthesis 1996, 1455.

(22) Vinod, T.; Hart, H. J. Org. Chem. 1990, 55, 881.

61 Chapter 3. A New Twist on PCP Diphosphine Pincer Complexes

3.1 Introduction

PCP-type pincer ligands and complexes have been studied extensively since 1970s.1-13 The name bestowed upon these ligands12 reflects their tenacious and tridentate binding nature. If one considers the most well-known pincer ligand platform, the m-xylyl framework

- [2,6-(DCH2)2C6H3] (an DCD pincer, D = donor atoms or groups such as NR2, PR2, OR, etc.,

Scheme 3.1, top), one can envision how the presence of a formal negative charge and two exemplary five-membered chelate rings can impart great stability to such complexes. More recently, related pincer ligands have been constructed featuring N-heterocyclic carbenes as

C-donors (DCD and CDC types) that vastly increase the diversity of this ligand class. Many of these systems are also designed such that the central, "anchoring" donor atom is often part of a planar group (such as a phenyl, pyridine, or N-heterocyclic carbene group). It has been recognized that if this ring is not in the plane containing the metal and the two outer donor atoms, then a twisted conformation is realized. The C2 symmetric, and hence, chiral nature of these complexes offer the potential of resolution and use in performing catalytic enantioselective transformations. Interconversion between these two atropisomers (Scheme 3.1, a and a’), however, prevents isolation of individual enantiomers and behaves as an "averaged" planar structure (Scheme 3.1, a"). Highly twisted structures have been produced,14-19 and configurationally stability for a twisted 2,6-lutidinyl-biscarbene complex was maintained up to

80°C.18 It should be mentioned that chiral pincer ligands have been reported that include modifications to the methylene carbons or through the use of stereogenic centers at the donor atoms of this versatile motif.20-26 In this thesis not only has the attainment of the highest twist angles to date been demonstrated, but also systems having a very high degree of non-fluxionality

62 and versatility.

a pincer-binding motif D M D

atropisomers D D

k1 M M k-1 Φ D aa'D

D M D

averaged structure a"

Scheme 3.1. Typical " pincer" binding and atropisomers.

The strategy was inspired by our past success in employing m-terphenyls to stabilize various materials having low coordinate phosphorus atoms.27-29 Specifically, reposition phosphorus atoms on a terphenyl framework would lead to a new class of pincer ligands (Scheme 3.2). The initial efforts, however, were somewhat disappointing in that ligands of the form

[2,6-(2-R2PCH2C6H4)2C6H4] did not undergo cyclometallation and pincer complex formation upon reaction with Pd(II) salts (as [(2,6-(R2PCH2)2C6H4] ligands are able), but instead yielded complexes bearing trans-spanning diphosphines (Scheme 3.2, left).30,31 Following a common work-around, installation of a more reactive halogen atom in place of a hydrogen atom at the critical C-1 position of the central ring afforded ligand precursors that readily reacted with low-valent complexes to provide new C2-symmetric pincer complexes 3.1-3.4 (Scheme 3.2, right).

X = Br X R = Ph (2.13) Cy (2.14) t-Bu (2.15) R2P PR2 X = H

PdCl2(NCPh)2 or Pd2(dba)3 NiCl2(DME) or Ni(COD)2

R2P

R2P M Br

Cl M Cl PR2 R2P

M = Pd (3.1-3.3), Ni(3.4)

Scheme 3.2. Relationship between previous trans-spanning (left) and new pincer complexes (right).

64 3.2 Results and discussion

3.2.1 Synthesis

Despite of the fact that the diphosphine ligands 2.13-2.15 show two stable conformations syn- and anti- on the NMR time scale, diphosphines 2.13-2.15 react with Pd2(dba)3 to quantitatively yield pincer complexes 3.1-3.3 (Scheme 3.2, right). Evidences of formantion of new species have been indicated by new signals ca 25-35 ppm downfield from corresponding free ligands in the 31P NMR spectra, which are 26.3, 33.7 and 55.1 ppm, respectively. Likewise, reaction of

31 2.13 with Ni(COD)2 yield an analogous nickel pincer complex 3.4, and the corresponding P

NMR chemical shift is 27.0 ppm. While reaction of 2.13 with Pd2(dba)3 is rapid and complete in one hour at room temperature to yield 3.1, reaction of the more hindered 2.15 with Pd2(dba)3 requires 12 or more hours for completion. These new pincer complexes are robust and display great air stability and can be purified by flash column chromatography on silica gel under ambient condition.

3.2.2 NMR Spectroscopy Studies

Upon analysis of NMR spectroscopy of 3.1-3.3 and 3.4, all the resonances can be assigned to specific proton or carbon atoms. This NMR technique includes one dimensional (1H NMR, 13C

NMR) and two dimensional (COSY, HMQC and HMBC) NMR spectroscopy. The weakest resonances in 13C NMR spectra were the carbons attached to the metal center. For 3.1, the

Ar(C)-Pd carbon resonance was assigned to 146.5 ppm, while 145.9 ppm for 3.2 and 145.6 ppm for 3.3. The methylene protons are recognized as AB patterns showing up as two sets of doublet of pseudo triplets which are coupled by phosphorous atoms. The carbon resonance for methylene carbon appear at about 30 ppm which is also a pseudo triplet coupled by phosphorous

65 atoms. The detailed assignments for 3.1 are described at the following figures (Figure 3.1 and

Figure 3.2).

HA/HB HA/HB

H Ph Ph 4 H 5 3 H 6 P 8 2 9 1 7 10 Pd 12 H H 11 25 H HA Br HB P 24 19 13 14 23 20 18 15 22 21 17 16 H15 H21

H20, H10, H11 H5 H14 H16 H22 H12

1 Figure 3.1. H NMR spectra of 3.1 (CDCl3, 600 MHz) and detailed assignments

C25 C7 C1 C2

H Ph Ph 4 H 5 3 H 6 P 8 2 9 1 7 10 Pd 12 H H 11 25 H HA Br HB P C3 24 19 13 14 23 20 18 15 C11 22 21 17 16 C16 C22 C21 C9 C3

C20 C14 C12 C10

C8 C C13 4 C19

13 Figure 3.2. C NMR spectra of 3.1 (CDCl3, 150 MHz) and detailed assignments

67 3.2.3 Crystal Structure Analyses

Complexes 3.1-3.3 were further characterized by single-crystal X-ray diffraction analysis

(Figure 3.3-5, Table 3.1). The crystal structure of 3.1 reveals a four-coordinate planar palladium(II) center, as well as a crystallographically imposed C2 axis passing through the bromine, palladium and C(1) atoms. Although individual molecules of 3.1 are chiral, the crystal is comprised of both enantiomers that are related by a crystallographic inversion center.

The bond lengths of Pd-P and Pd-C are in reasonable agreement with published values for PCP pincer complexes.32-36 Compared to the known closely related PCP pincer complex

36 [(C6H3(CH2PPh2)2)PdBr)] (3.5), having P-Pd-C bond angles of 80.6° and 81.8°, complex 3.1 has C(1)-Pd-P bond angles of 84.74°. These values are actually closer to the non-pincer analog

37 trans-[(PPh3)2Pd(C6H5)Br] (86.3° and 88.8°) that does not posses any ring constraints . The most striking difference between the solid state structures of 3.1 and 3.5 lies in the distortion of P atoms away from the plane of containing the anchor atom C(1), its ring, and the Pd and Br atoms. One can assign a "twist" angle Φ (see Scheme 3.1) defined as the angle between the plane of the anchoring ring and square plane containing the metal and its four directly attached atoms to assess this effect for comparative purposes. A Φ value of 76.0° for 3.1 greatly surpasses the Φ = 18.4° found for 3.5.36 The twist angle for 3.1 is also 34° greater than that found for CDC pincer complexes (C = N-heterocyclic carbene) having the largest Φ values reported to date (up to 41.8°).14-19

Figure 3.3. ORTEP drawing (20% probability ellipsoids) of the molecular structure of 3.1.

Hydrogen atoms are omitted for clarity.

Figure 3.4. ORTEP drawing (40% probability ellipsoids) of the molecular structure of 3.2.

Hydrogen atoms are omitted for clarity.

Figure 3.5. ORTEP drawing (40% probability ellipsoids) of the molecular structure of 3.3.

Hydrogen atoms are omitted for clarity.

Table 3.1. Selected bond lengths (Å) and angles (°) for complexes 3.1-3.3.

Complexes 3.1 3.2 3.3

Pd1-C1 2.067(4) 2.037(2) 2.061(5) Pd1-P1 2.3071(7) 2.3442(4) 2.387(1) Pd1-P2 2.3071(7) 2.3142(4) 2.398(1) Pd1-Br1 2.5024(5) 2.5256(2) 2.5072(6) C1-Pd1-Br1 180.000(1) 167.37(5) 177.1(1) P1-Pd1-P2 169.48(4) 173.38(2) 178.85(4) Twist angle 76.68 72.47 67.56

70 Complexes 3.2 and 3.3 display the similar structures as 3.1. However they show some difference in bond lengths and angles due to the differences in the steric bulk of the diphosphines.

The more steric hindrance of the diphosphine the longer Pd-P bond is observed. The Pd1-P1 bond length increases from 3.307 Å to 3.387 Å as from the less bulky -PPh2 (1a) to the bulkiest

t –P Bu2 (3.3), while bond angle of P1-Pd-P2 increases from 169.5º to 178.9º, as well. This steric effect is also indicated by the difference of the twist angle. The most bulky diphosphine (3.3) shows the smallest twist angle among these three pincer complexes.

3.2.4 Variable Temperature NMR Studies

In order to assess the structural rigidity of the pincer platform, the variable temperature 1H

NMR of 3.1 and 3.3 was investigated in detail. For a static or slowly exchanging (between atropisomers a and a') structure, the two diastereotopic benzyl protons of some previously reported pincer complexes can be resolved, and at increased temperatures show coalescence phenomena indicative of fast exchange between atropisomers. Our studies of 3.1 have determined that the 1H NMR signals for the benzyl protons are both highly temperature and solvent dependent in a complicated manner. In CD2Cl2 or CDCl2CDCl2, the two sets of benzyl protons are well separated (a pair of virtual triplets for each signal, Figure 3.6) at room temperature. At higher temperatures up to 130°C in CDCl2CDCl2, the signals show no evidence for exchange, and, in fact, seem to move further apart. Cooling a solution of 3.1 in

CD2Cl2 can bring about a "phantom" coalescence temperature of about -75 °C.

71 HA/HB HB/HA

Ph Ph

HA Br HB P

Ph Ph 3.1

1 Figure 3.6. Variable temperature H NMR (600 MHz) of 3.1 in CD2Cl2 (top) and in

CDCl2CDCl2 (bottom) for methylene region.

72 Similar experiments on compound 3.1 in dmso-d6 also reveal a "phantom" coalescence temperature of about 100°C, above which these signals remain as an unresolved broad signal

(Figure 3.7). Since the analysis of the benzyl protons can be unreliable and unpredictable, analysis of the 1H NMR data for the two Ph groups on the phosphorus atoms could be more reliable. At all temperature the sets of protons corresponding to the Ph groups proximal and distal to the Br atom showed no evidence for exchange (Figure 3.8-3.10).

1 Figure 3.7. Variable temperature H NMR (600 MHz, dmso-d6) of 3.1 for methylene region.

1 Figure 3.8. Variable temperature H NMR (600 MHz, CD2Cl2) of 3.1 for aromatic region.

1 Figure 3.9. Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.1 for aromatic region.

1 Figure 3.10. Variable temperature H NMR (600 MHz, DMSO-d6) of 3.1 for aromatic region.

76 Analysis of spectra for the tert-butyl derivative 3.3 (Figure 3.11) was much clearer. At low temperature, the two types of tert-butyl groups are inequivalent, and remain so, up to 105°C in toluene-d8. One of the signals, however, is resolved into three independent methyl resonances at low temperature.

1 Figure 3.11. Variable temperature H NMR (600 MHz, toluene-d8) of 3.3 for alkyl region.

(methyl protons indicated by *)

This observation suggests that the tert-butyl groups most proximal to the bromine atom face steric clashes with the bromine atom and cause hindered rotation about the C-CMe3 bond, and thus results in three inequivalent methyl groups. However the resonances of methylene protons show a different and complicated pattern. These resonances do not show well separated two sets of doublet of pseudo triplets as in some other solvent, such as CDCl3 (Figure 3.12).

77 Instead, a single signal was observed around 45 ºC, while increase or decrease the temperature this resonance split into four peaks. This different behavior as compared to different solvents further support our assumption that it is not reliable to analyze the signal exchange of methylene proton resonances to evaluate the rigidity of this type of pincer complexes.

If the atropisomerization process depicted in Scheme 3.1 were occurring, the two types of tert-butyl groups would undergo exchange and lead to NMR broadening. In contrast, the pincer

t 1 t 38 PCP complexes [(C6H3(CH2P Bu2)2)PdCl)] and [(C6H3(CH2P Bu2)2)Pd(THF-d8))]BF4 only show a single 1H NMR resonance for their freely rotating and equivalent tert-butyl groups.

1 Figure 3.12. Variable temperature H NMR (600 MHz, CDCl3) of 3.3 for alkyl region.

78 These variable temperature NMR spectroscopy analyses shown above demonstrate that these pincer complexes feature rigid backbones without interconversion of atropisomers even at elevated temperature. However, there is another unsolved mystery about complex 3.3.

31 When a specific solvent CDCl2CDCl2 (or CHCl2CHCl2) is chosen, the VT P NMR spectra of

3.3 show a usual pattern (55.6 ppm) at temperature higher than room temperature. However a second species is showing up at 60.5 ppm when the temperature is lowered (Figure 3.13).

31 Figure 3.13. Variable temperature P NMR (243 MHz, CDCl2CDCl2) of 3.3. (* indicates a

new species upon lowering the temperature)

79 Upon analysis of the 1H NMR, some new peaks both at alkyl region and aromatic region are also observed at low temperature (Figure 3.14, 3.15). There is no such phenomenon observed when using CDCl3, toluene-d8 and CD2Cl2 as NMR solvents. One of the possibilities could be the interaction between the solvent molecules and the complex molecules. Therefore some more other solvents including CH2ClCH2Cl, CH2BrCH2Br, CH3CH(Cl)CH3, CHBr2CHBr2 and

31 CH2ClCCl3 were used to repeat the variable temperature P NMR experiments. Only one peak at ~53 ppm was observed, however.

1 Figure 3.14. Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.3, alkyl region

(* indicates a new species upon lowering the temperature).

1 Figure 3.15. Variable temperature H NMR (600 MHz, CDCl2CDCl2) of 3.3, aromatic region

(* indicates a new species upon lowering the temperature).

81 3.3 Conclusion

In summary, we have prepared new pincer ligands constructed by m-terphenyl scaffolds, and showed their efficacy in yielding novel palladium and nickel pincer complexes. Structural analysis of 3.1-3.3 shows that despite a larger chelate ring size than earlier conventional pincer complexes (compare 7 to 5), the new pincer complexes better match the metrical parameters found for related unconstrained non-chelate structures. In addition, these systems have the greatest twist angles determined to date for pincer complexes and also display a very high degree of non-fluxionality (up to 130°C). These air and thermally stable materials thus hold much potential for resolution and use in catalysis. Efforts are now ongoing to resolving the enantiomers of 3.1-3.3, and to examine their catalytic behavior relative to conventional pincer complexes. Finally, this work should remind one to the potential risks associated with assessing the degree of flexibility of ring systems where there may also be an inherent temperature dependence, as well a solvent dependence, of key NMR resonances.39,40

82 3.4 Experimental

General Procedures and Materials

Experiments were carried out using standard Schlenk techniques or in a glove box under nitrogen. Certified A.C.S. grade solvents (diethyl ether, CCl4, CH2Cl2, ethanol, methanol, hexanes, ethyl acetate), anhydrous acetone from Fisher were used as received. Anhydrous solvents (THF, benzene) were distilled from Na/benzophenone prior to use. The NMR spectroscopy measurements were recorded on Varian Inova 400 or 600 MHz spectrometers.

Chemical shifts given in ppm were referenced to residual solvent signals (1H, 13C NMR) or

31 external 85% H3PO4 as reference ( P NMR). Elemental analyses were performed by

Quantitative Technologies, Inc. NJ.

[2,6-(2-CH2PPh2C6H4)2C6H3PdBr] (3.1)

A mixture of 2.13 (0.80 g, 1.1 mmol) and Pd2(dba)3 (0.50 g, 0.55 mmol) were dissolved in anhydrous benzene (20 mL), and stirred at room temperature for overnight. The resultant solution was filtered and the solvent was removed in vacuo. The crude mixture was chromatographed over silica gel using ethyl acetate/hexanes (1:4 v/v) as eluent to afford 0.40 g

3.1 as pale yellow crystalline solid (45%).

1 H NMR (CDCl3, 600 MHz): δ 2.91 (doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 3.21

(doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 6.38 (m, 2H), 6.65 (d, JHH = 7 Hz, 2H), 6.73

(d, JHH = 7 Hz, 2H), 7.02 (t, JHH = 7 Hz, 1H), 7.10-7.15 (m, 8H), 7.20 (t, JHH = 7 Hz, 4H), 7.28 (t,

13 1 JHH = 7 Hz, 2H), 7.45 (t, JHH = 7 Hz, 4H), 7.57 (t, JHH = 7 Hz, 2H), 7.58-7.61 (m, 4H). C { H}

NMR (CDCl3, 150 MHz): δ 32.1 (virtual triplet, JPC = 13 Hz, -CH2-), 124.9 (s), 126.4 (s), 127.3

(m), 129.0 (virtual triplet, JPC = 5 Hz), 129.5 (s), 129.6 (m), 130.0 (s), 130.6 (s), 131.0 (virtual triplet, JPC = 20 Hz), 132.0 (s), 133.6 (virtual triplet, JPC = 22 Hz), 133.70 (virtual triplet, JPC = 7

83 Hz), 133.84 (virtual triplet, JPC = 5 Hz), 145.0 (virtual triplet, JPC = 3 Hz), 146.7 (s, Ar(C)-Pd-),

31 147.3 (virtual triplet, JPC = 4 Hz). P NMR (CDCl3, 162 MHz): δ 26.3 (s). Elemental analysis calcd for C44H35BrP2Pd (812.03): C, 65.08; H, 4.34. Found: C, 64.90; H, 4.13.

[2,6-(2-CH2PCy2C6H4)2C6H3PdBr] (3.2)

To a mixture of 2.14 (0.30 g, 0.42 mmol) and Pd2(dba)3 (0.23 g, 0.26 mmol), 15 mL benzene was added, and mixture was stirred overnight at room temperature. The resultant solution was filtered and solvent was removed in vacuo. The crude product was chromatographed over silica gel using ethyl acetate/hexanes (1:10 v/v) as eluent to afford 0.16 g 3.2 as pale yellow crystalline solid (47%). Analytical pure product was obtained via recrystallization from CHCl3/hexanes.

1 H NMR (CDCl3, 400 MHz): δ 1.08-1.82 (m, 38 H, cyclohexyl), 1.97 (d, JHH = 12 Hz, 2H), 2.13

(s, 2H), 2.79 (m, 2H), 2.53 (doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 2.84 (doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 6.75 (d, JHH = 8 Hz, 2H), 7.04 (t, JHH = 8 Hz, 1H),

13 1 7.22-7.25 (m, 4H), 7.27-7.31 (m, 2H), 7.34 (d, JHH = 7 Hz, 2H). C { H} NMR (CDCl3, 100

MHz): δ 23.7 (virtual triplet, JPC = 10 Hz, -CH2-), 26.0 (s), 26.9 (s), 27.1(virtual triplet, JPC = 6

Hz), 27.3-27.7 (m), 28.5(s), 28.8 (s), 28.9 (s), 30.4 (s), 35.2 (virtual triplet, JPC = 10 Hz), 36.3

(virtual triplet, JPC = 10 Hz), 124.1 (s), 126.4 (s), 126.6 (s) 128.6 (s), 129.9 (s), 130.2 (s), 134.3

(s), 146.0 (virtual triplet, JPC = 3 Hz), 147.4 (m, upon analysis of 2-D NMR (H-COSY, HMQC and HMBC), the carbon resonance of Ar(C)-Pd is overlapping with the virtual triplet at 147.4

31 ppm). P NMR (CDCl3, 162 MHz): δ 33.7 (s). Elemental analysis calcd for

C44H59BrP2Pd·CHCl3: C, 56.56; H, 6.33. Found: C, 56.68; H, 6.22.

t [2,6-(2-CH2P Bu2C6H4)2C6H3PdBr] (3.3)

To a mixture of 2.15 (0.30 g, 0.48 mmol) and Pd2(dba)3 (0.27 g, 0.29 mmol), 25 mL benzene

84 was added, and the mixture was stirred overnight at room temperature. The resultant solution was filtered and the solvent was removed in vacuo. The crude product was chromatographed over silica gel using ethyl acetate/hexanes (1:4 v/v) as eluent to afford 0.23 g 3.3 as pale yellow crystalline solid (66%). Analytical pure product was obtained via recrystallization from

CHCl3/hexanes.

1 H NMR (CDCl3, 400 MHz): δ 1.29 (virtual triplet, JPH = 7 Hz 18H, -C(CH3)3), 1.32 (broad,

6H, -C(CH3)3), 1.59 (broad, 6H, -C(CH3)3), 1.84 (broad, 6H, -C(CH3)3), 2.69 (doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 2.93 (doublet of virtual triplets, JHH = 13 Hz, 2H, -CH2-), 6.58

13 (d, JHH = 8 Hz, 2H), 6.94 (t, JHH = 8 Hz, 1H), 7.22 (m, 2H), 7.32 (m, 4H), 7.37 (m, 2H). C

1 { H} NMR (CDCl3, 100 MHz): δ 23.7 (virtual triplet, JPC = 10 Hz, -CH2-), 31.3 (virtual triplet,

JPC = 2 Hz, -C(CH3)3), 32.2 (broad, -C(CH3)3), 36.4 (virtual triplet, JPC = 5 Hz, -C(CH3)3), 38.8

(virtual triplet, JPC = 7Hz, -C(CH3)3), 124.1 (s), 126.1 (s), 126.9 (s), 129.3 (s), 129.5 (s), 130.2

(s), 134.5 (s), 146.3 (virtual triplet, JPC = 3 Hz), 147.0 (s, Ar(C)-Pd), 148.6 (virtual triplet, JPC =

31 3 Hz). P NMR (CDCl3, 162 MHz): δ 55.1 (s). Elemental analysis calcd for

C36H52BrP2Pd·1/3 CHCl3: C, 56.54; H, 6.70. Found: C, 56.41; H, 6.67.

[2,6-(2-CH2PPh2C6H4)2C6H3NiBr] (3.4)

A mixture of 2.13 (0.070 g, 0.099 mmol) and Ni(COD)2 (0.026 g, 0.095 mmol) were dissolved in anhydrous benzene (10 mL), and stirred at room temperature for overnight. The resultant solution was filtered and solvent was removed in vacuo. The crude product was chromatographed over silica gel using ethyl acetate/hexanes (1:4 v/v) as eluent to afford 0.040 g

3.4 as pale yellow crystalline solid (55%).

1 H NMR (CDCl3, 400 MHz): δ 2.71 (doublet of virtual triplets, JHH = 12 Hz, 2H, -CH2-), 3.04

(doublet of virtual triplets, JHH = 12 Hz, 2H, -CH2-), 6.26 (m, 2H), 6.58 (d, JHH = 7 Hz, 2H), 6.68

85 (d, JHH = 7 Hz, 2H), 6.94 (t, JHH = 7 Hz, 1H), 7.07-7.18 (m, 12H), 7.25 (t, JHH = 7 Hz, 2H), 7.46

13 1 (t, JHH = 7 Hz, 4H), 7.57-7.65 (m, 6H). C { H} NMR (CDCl3, 150 MHz): δ 31.6 (virtual triplet, JPC = 13 Hz, -CH2-), 124.5 (s), 126.3 (s), 126.6 (m), 127.2 (virtual triplet, JPC = 5 Hz),

127.5 (s), 129.0 (virtual triplet, JPC = 5 Hz), 129.3 (s), 129.4 (m), 129.5 (s), 130.3 (s), 131.0

(virtual triplet, JPC = 18 Hz), 132.1 (s), 133.2 (virtual triplet, JPC = 6 Hz), 133.7 (virtual triplet,

JPC = 5 Hz), 134.8 (virtual triplet, JPC = 20 Hz), 144.7 (s), 145.6 (virtual triplet, JPC = 33 Hz,

31 Ar(C)-Ni-), 149.1 (virtual triplet, JPC = 3 Hz). P NMR (CDCl3, 162 MHz): δ 27.0 (s).

86 NMR Spectra

31 Figure 3.16. P NMR spectrum of 3.1 (CDCl3, 162 MHz)

1 Figure 3.17. H COSY spectrum of 3.1 (CDCl3, 600 MHz)

Figure 3.18. 600 MHz 1H-detected 1H-13C correlation (HMQC) spectrum of 3.1.

Figure 3.19. 600 MHz 1H-detected 1H-13C correlation (HMBC) spectrum of 3.1.

31 Figure 3.20. P NMR spectrum of 3.2 (CDCl3, 162 MHz)

1 Figure 3.21. H NMR spectrum of 3.2 (CDCl3, 400 MHz)

1 Figure 3.22. H NMR spectrum of 3.2, expansion of aromatic region (CDCl3, 400 MHz).

13 Figure 3.23. C NMR spectrum of 3.2 (CDCl3, 100 MHz).

13 Figure 3.24. C NMR spectrum of 3.2, expansion of alkyl region (CDCl3, 100 MHz).

13 Figure 3.25. C NMR spectrum of 3.2, expansion of aromatic region (CDCl3, 100 MHz).

31 Figure 3.26. P NMR spectrum of 3.3 (CDCl3, 162 MHz)

13 Figure 3.27. C NMR spectrum of 3.3 (CDCl3, 100 MHz).

13 Figure 3.28. C NMR spectrum of 3.3, expansion of aromatic region (CDCl3, 100 MHz).

13 Figure 3.29. C NMR spectrum of 3.3, expansion of alkyl region (CDCl3, 100 MHz).

31 Figure 3.30. P NMR spectrum of 3.4 (CDCl3, 162 MHz)

1 Figure 3.31. H NMR spectrum of 3.4 (CDCl3, 400 MHz)

1 Figure 3.32. H NMR spectrum of 3.4, expansion of aromatic region (CDCl3, 400 MHz).

13 Figure 3.33. C NMR spectrum of 3.4(CDCl3, 150 MHz).

13 Figure 3.34. C NMR spectrum of 3.4, expansion of aromatic region (CDCl3, 150 MHz).

98 3.5 Works Cited

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101 Chapter 4. NCN Diimine Pincer Ligands and Complexes

4.1 Introduction

Transition metal complexes containing pincer type ligands have attracted broad interest1-5 for a spectrum of applications since the first report of these materials.6 Among the many types of pincer complexes, those containing PCP, NCN and SCS donor sets are the most investigated.

These pincer compounds are also predominantly constructed upon a m-xylyl framework

- ([2,6-(DCH2)2C6H3] , D = donor atoms or groups such as NR2, PR2, SR, etc. Chart 4.1, left).

Since pincer complexes catalyze many reactions, such as Heck coupling reactions7-12 and catalytic dehydrogenation of alkanes,13-16 analogous chiral pincer complexes could offer much promise for asymmetric catalysis. However, only a limited number of examples have been reported.17-20 Chirality can be introduced into these “traditional” pincer complexes by addition of appropriate substituents onto either the methylene groups or donor atoms.21 Some recent papers have also reported pincer-type complexes having other anchoring rings and/or ring sizes for the metallacycles as alternative ways to generate C2 symmetric and potentially chiral complexes (Chart 4.1, right).22-24 In these systems, one can characterize the deformation from planarity of the D-M(L)-D plane from that plane including the anchoring ring by a "twist angle"

Φ (Chart 4.1, right). Facile interconversion between the two possible atropisomers, however, can yield effective non-chiral planar geometries.22 In the previous the chapter (Chapter 3), a series of PCP pincer complexes constructed upon m-terphenyl backbones that display rigid structures have been introduced, which show large twist angles Φ from 67.6 to 76.7º.25

102 D N N N n M D M D D M D D M D n D Φ° L L L Chart 4.1. Twist angle Φ of pincer complexes.

As compared to air sensitive PCP pincer ligands, NCN analogs offer more stability.26 The properties of some of the NCN-pincer complexes can also be further tuned by introduction of different functional groups to the pincer backbone.1 NCN pincer complexes have been used many catalytic systems, such as Michel reaction,27 aldol condensation,28 and Heck coupling reactions.20 Some examples of NCN diimine pincer complexes 4.1,27 4.228 and 4.320 are shown in Chart 4.2. It was thus of immediate concern to establish if NCN pincer ligands and complexes containing m-terphenyl scaffolds could be produced. This chapter shows the details of the successful synthesis and characterization of new high twist angle NCN diimine palladium pincer complexes.

X BF4 O O O O N Pd N N N N Pd N Pt I R' R R R R' R OH2 OH2

4.1 4.2 4.3

Chart 4.2 Examples of NCN diimine pincer complexes.20,27,28

103 4.2 Results and Discussion

4.2.1 Synthesis

As often noted, the synthesis of NCN pincer complexes can be unpredictable, and often fails from the corresponding NC(H)N ligand precursors.29-31 This sort of problem with m-terphenyl

PC(H)P ligand precursors has been overcome by utilizing PC(Br)P precursors. In anticipation of similar challenges for generating m-terphenyl NCN ligands, ligand NC(Br)N precursor 4.6 from 4.425,32,33 has been prepared. This material, however, only yielded a precipitate of palladium metal over time, and no evidence for discernable complexes upon mixing with

Pd2(dba)3. Undaunted, precursors having carbon-iodine bonds that would be more susceptible to oxidative addition have been prepared. This approach readily yields the desired ligand precursors 4.7-4.10 in good yields (Scheme 4.1) as air stable pale yellow crystalline solids.

O O RN NR RNH2 Δ

X C6H6, p-TsOH (cat.) X

4.4: X = Br 4.6: X = Br; R = Ph (80%) 4.5: X = I 4.7: X = I; R = Ph (78%) 4.8: X = I; R = Cy (97%) 4.9: X = I; R = 2,6-(CH3)2Ph (90%) 4.10: X = I; R = 2,4,6-(CH ) Ph (92%) 3 3 Scheme 4.1. Synthesis of diimine pincer ligands precursors.

While ligand precursors 3-7 appear to exist as mixtures of syn and anti isomers (as assayed by

1H NMR spectroscopy, syn isomers portrayed in Scheme 4.1), reaction of 4.7-4.10 with

Pd2(dba)3 produce pincer complexes 4.11-4.14 resulting from the formal selective addition of the anti-isomers. There exists a C2 symmetric environment in the m-terphenyl scaffold for complexes 4.11-4.14, therefore these complexes are racemic mixtures. Only one of the two

104 enantiomers for complexes 4.11-4.14 are shown in Scheme 4.2 and their figures of ORTEP drawings representing the crystal structures which will be discussed in the following section.

R N RN NR

Pd2(dba)3 Pd I C6H6, rt I N R 4.7: R = Ph 4.11: R = Ph (45%) 4.8: R = Cy 4.12: R = 2,6-(CH3)2Ph (65%) 4.9: R = 2,6-(CH3)2Ph 4.13: R = 2,4,6-(CH3)3Ph (69%) 4.10: R = 2,4,6-(CH ) Ph 4.14: R = Cy (59%) 3 3 Scheme 4.2. Synthesis of palladium diimine pincer complexes.

There are two possible routes for the palladium atoms to add into the system and form pincer complexes (Scheme 4.3). The Pd(0) will coordinate to the nitrogen donor of one of the two arms of diimine ligand positioning the metal for oxidative addition to the carbon-halogen bond, followed by coordination of the other arm of the diimine ligand. In the final step the syn- form would be expected to rotate to the position that is anti- to the first arm, leading to the observed pincer complex (i). The second possible route could be the oxidative addition of Pd(0) into the carbon-halogen bond followed by diimine ligand coordination to the Pd(II) atom to form the final pincer complex (ii).

105 X Pd Pd N X Ar N Pd N Ar N X N N Ar Ar Ar Ar

Ar Ar Ar N N N

X Pd Pd Pd N X N X N Ar Ar Ar (i) (ii)

Ar N

X N Ar

Scheme 4.3. Two different routes of oxidative addition of Pd(0) to Ar-X bond.

Since bromine substituted diphosphine precursors have previously been employed for the synthesis of PCP pincer complexes bearing similar m-terphenyl scaffolds,25 the reason for the difference in behavior of diimines outlined in Scheme 4.1 could be rationalized based on differences in electron density at palladium, i.e. more electron-rich palladium (with one or both phosphines) is more easily oxidized to Pd(II) via oxidative addition. If route (ii) is the process for forming such type of pincer complexes, NCN pincer ligand precursor 4.6 should have undergone the oxidative addition when mixed with Pd2(dba)3, since there is not much difference for the C-Br bond of 4.6 and the reported diphosphine ligand precursor. Therefore, based on the different behavior of 4.6 and 4.7, route (i) is likely the way to produce such NCN pincer complexes.

106 4.2.2 Crystal Structure Anslysis

Single crystals of compound 4.11-4.14 suitable for analysis by X-ray diffraction were grown by slow diffusion of hexanes into chloroform or methylene chloride solutions. The structures of 4.11-4.14 are given in Figures 4.1-4 and the selected bond lengths and bond angles are shown in Table 4.1.

Figure 4.1. ORTEP drawing of the molecule structure of 4.11 (40% probability ellipsoids).

Hydrogen atoms and solvent molecule (CHCl3) are omitted for clarity.

The structure of 4.11 shows slightly distorted square planner geometry for the palladium (II) center. The bond lengths of Pd-C1, Pd-N1, Pd-N2 and Pd-I1 are comparable to related values that reported for NCN palladium pincer complexes.23,27,28,34,35 The plane containing the directly attached phenyl ring and the Pd atom is twisted by 64.9° from that of the coordination plane containing the Pd, C1, I1, N1 and N2 atoms. This "twist angle" is 14º greater than the largest previously reported NCN pincer complex,24 but is somewhat smaller than for related m-terphenyl

107 based PCP complexes.25 Because of the larger seven-membered rings within 4.11, the N1-Pd-N2 bond angle (174.15º) is larger than m-xylyl based NCN pincer complexes27,28,34,35 having five-membered rings (~159º to 163º).

Figure 4.2. ORTEP drawing of the molecule structure of 4.12 (40% probability ellipsoids).

Hydrogen atoms are omitted for clarity.

108

Figure 4.3. ORTEP drawing of the molecule structure of 4.13 (40% probability ellipsoids).

Hydrogen atoms are omitted for clarity.

Figure 4.4. ORTEP drawing of the molecule structure of 4.14 (40% probability ellipsoids).

Hydrogen atoms are omitted for clarity.

109 Table 4.1. Selected bond lengths (Å) and angles (°) of complexes 4.11-4.14.

Complex 4.11 4.12 4.13 4.14

Pd1-C1 1.971(2) 2.005(2) 2.010(2) 1.980(3)

Pd1-N1 2.025(2) 2.055(2) 2.051(1) 2.033(2)

Pd1-N2 2.023(2) 2.055(2) 2.055(1) 2.034(2)

Pd1-I1 2.7024(3) 2.7089(2) 2.7163(1) 2.7139(3)

C1-Pd1-I1 173.56(7) 179.24(5) 178.10(4) 175.60(8)

N1-Pd1-N2 174.15(7) 177.39(6) 177.89(4) 173.94(9)

Twist angle 64.90 62.74 61.46 64.96

Comparing the structures of complexes 4.12 and 4.13 to complexes 4.11 and 4.14, the more bulky 4.12 and 4.13 have longer Pd-N and Pd-C1 bond lengths than those of less bulky 4.11 and

4.14, and their bond angles of C1-Pd-I1 are closer to linear 180 º. Also the steric bulk has the effect on the twist angles. It is likely that the more bulky the imine group in this type of diimine pincer complex the smaller the twist angle. This is similar to the diphosphine pincer complexes described in the previous chapter. The crystal structures of complexes 4.12, 4.13 and

4.14 likewise show large twist angles of 62.8°, 61.5° and 65.0° respectively.

110 4.2.3 NMR Spectroscopy Studies

The methyne protons (CH=NR) in complexes 4.11-4.14 appear as singlets at δ8.44, 8.13, 8.10

1 and 8.16 ppm respectively, in H NMR spectra recorded in CDCl3. These resonances are about

0.2 ppm downfield shifted compared with their precursors 4.7-4.10. The corresponding 13C

NMR resonances (CH=NR) are located at δ165.5, 172.1, 171.7 and 162.4 ppm for 4.11-4.14, respectively, which shifted downfield 6~10 ppm compared with free ligands 4.7-4.10. The 1H

NMR spectra of complexes 4.12 and 4.13 show broad peaks in the methyl and aromatic regions, suggesting hindered rotation of the xylyl and mesityl ring along the C1-N bond (Figure 4.5).

Figure 4.5. Illustration showing how hindered rotation about N-Ar bond of complex 4.13 distinguishes methyl groups a and a’ (other hydrogen atoms omitted for clarity).

In order to elucidate the details of this process, a series of variable temperature NMR experiments were thus conducted to examine this phenomenon in greater detail. At low temperature (e.g. -25 ºC) three sharp resonances are discerned for the three mesityl methyl groups of complex 4.13 (Figure 4.6, left) . As the temperature is raised, two of the three signals

(a and a’) begin to broaden and approach coalescence at 55°C. Similar behavior is observed for compound 4.11 (Figure 4.7, left). These NMR spectra were simulated by using line shape

111 analysis software WINDNMR-Pro36 (Figure 4.6, right; Figure 4.7, right). An Eyring plot and the resulting activation parameters are presented in Figure 4.8.

1 Figure 4.6. Temperature dependant H NMR (600 MHz, CDCl3) spectra of 4.13 (left), and simulated 1H NMR spectra (right) for resonances a and a’.

1 Figure 4.7. Temperature dependence H NMR (600 MHz, CDCl3) spectra of 4.12 (left), and the simulated 1H NMR spectra (right).

112

Figure 4.8. Eyring plots of ln(k/T) vs. 1/T for complex 4.12 (■), and complex 4.13 (△).

The data are consistent with hindered rotation about the N-Ar bond of 4.12 and 4.13 (Figure

4.5), caused by the fact that the m-terphenyl framework places the N-Ar methyl groups in close proximity to the halogen atom. This hypothesis is consistent with similar hindered P-C bond

t 25 rotation in [2,6-(2- Bu2PCH2C6H4)2C6H3PdBr], of which the rotation barrier is 10.0 kcal/mol.

Relatively larger values are found for complexes 4.12 and 4.13, which are 15.2 and 15.7 kcal/mol. Such rotation barrier in complex 4.12 is close to complex 4.13 due to their similar structures.

113 4.3 Conclusion

In summary, new diimine NCN pincer ligands based upon m-terphenyl scaffold have been synthesized, and their palladium complexes prepared by an oxidative route. Structure analyses of 4.11-4.14 reveal a formal C2 symmetric environment. In addition this system shows the greatest “twist” angle to date for NCN pincer complexes, a property that might be utilized for resolution of chiral pincer complexes with high degree of non-fluxionality. Variable temperature NMR spectroscopic studies of 4.12 and 4.13 indicated hindered rotation about the

N-Ar bond, and possibly, a more crowded environment than analogous m-xylyl based pincer complexes.

114 4.4 Experimental

General Procedures and Materials

Experiments involving manipulation of air- and water sensitive materials were carried out using Schlenk techniques or in a glove box under nitrogen. Certified A.C.S. grade solvents (THF,

CCl4, CHCl3, CH2Cl2, benzene, hexanes, n-pentane, methanol, and ethanol) and anhydrous benzene from Fisher were used as received. Aniline, 2,6-dimethylaniline and

2,4,6-trimethylaniline were distilled prior to use. The NMR spectroscopy measurements were recorded on a Varian Inova 400 or 600 MHz spectrometers. Chemical shifts were referenced to residual solvent signals (1H, 13C NMR). Elemental analyses were performed by Quantitative

Technologies, Inc. NJ.

33 25,32 2,6-(2-CH3C6H4)2C6H3I (4a) and 2,6-(2-CH(O)C6H4)2C6H3Br (4.4) were synthesized according to literature methods.

2,6-(2-CHBr2C6H4)2C6H3I (4b)

To a solution of 4a (3.00 g, 7.81 mmol) in 200 mL CCl4 in a 500 mL round bottom flask,

N-bromosuccinimide (2.79 g, 15.7 mmol) and benzoyl peroxide (50 mg, 0.20 mmol) were added.

The solution was heated to reflux under N2 for 6 h, and another portion of N-bromosuccinimide

(3.14 g, 17.6 mmol) and benzoyl peroxide (50 mg, 0.20 mmol) were added. After an additional

18 h of reflux the mixture was cooled, and filtered. The filtrate was then washed with 5%

NaSO3 (100 mL × 3) and dried with anhydrous MgSO4. After filtration the solvent was evaporated and the remaining solid was washed with n-pentane and then dried in vacuo to yield

4.98 g (91.2%) of 4b as white solid.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

115 NMR (CDCl3, 400 MHz): δ 6.35 (s, CHBr2), 6.41 (s, CHBr2) 7.09-7.17 (m, 2H), 7.33-7.35 (m,

13 1 2H), 7.38-7.44 (m, 2H), 7.53-7.58 (m, 3H), 8.08-8.10 (m, 2H). C { H} NMR (CDCl3, 100

MHz): δ 38.9 (CHBr2), 39.0 (CHBr2), 104.9 (Ar(C)-I), 105.8 (Ar(C)-I), 128.4, 128.5, 129.2,

129.4, 129.5, 129.7, 129.76, 129.79, 130.1, 139.3, 139.4, 140.5, 140.7, 145.3, 145.4. Anal.

Calcd for C20H13Br4I: C, 34.32; H, 1.87. Found: C, 34.15; H, 1.52.

2,6-(2-CH(O)C6H4)2C6H3I (4.5)

A mixture of 4b (4.00 g, 5.72 mmol), silver nitrate (4.00 g, 23.5 mmol) and sodium acetate

(2.11 g, 25.7 mmol) in a 250 mL round bottom flask containing solvent mixture of 125 mL EtOH and 25 mL THF was heated to reflux under N2 for 16 h. After removal of solids by filtration the solvent was evaporated to yield a sticky compound. This sticky compound was dissolved in

CH2Cl2 (150 mL) and 5 mL hydrochloric acid (10%) was added. The reaction mixture was stirred at room temperature for 6 h, then washed with water (100 mL × 3) and dried with anhydrous MgSO4. The solvent was evaporated, and the crude product was washed with diethyl ether and then dried in vacuo to yield 1.98 g (84.0 %) of 4.5.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 9.88(CHO), 9.87 (CHO), 8.02-8.04 (m, 2H), 7.66-7.70 (m, 2H),

13 1 7.55-7.59 (m, 2H), 7.50-7.54 (m, 1H), 7.31-7.36 (m, 4H). C { H} NMR (CDCl3, 100 MHz):

δ 191.3 (CHO), 191.6 (CHO), 106.0 (Ar(C)-I), 127.9, 128.07, 128.15, 128.4, 128.99, 129.03,

129.9, 130.0, 130.9, 131.1, 133.6, 133.7, 133.9, 134.1, 144.58, 144.61, 148.0, 148.3. Anal.

Calcd for C20H13O2I: C, 58.27; H, 3.18. Found: C, 58.09; H, 2.88.

2,6-{2-PhN=C(H)C6H4}2C6H3Br (4.6)

To a benzene (40 mL) solution of 4.4 (1.00 g, 2.74 mmol) and aniline (0.60 g, 6.4 mmol) in a

116 100 mL round bottom flask, several pieces of crystalline p-toluene sulfonic acid were added.

The resultant mixture was heated to reflux under N2 for 16 h. Water generated by this reaction was collected by Dean-Stark receiver. After being cooled to room temperature, the solvent was removed under vacuum. The resultant material was recrystallized from a methanol/CH2Cl2 solvent mixture to yield 1.13 g (80 %) pale yellow crystalline solid of 4.6.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 8.22 (CH=NPh), 8.25 (CH=NPh), 6.94 (m), 7.06-7.10 (m),

7.21-7.38 (m), 7.45 (t, JHH = 7 Hz), 7.53-7.58 (m, 4H), 8.35-8.37 (m, 2 H). Anal. Calcd for

C32H23N2Br: C, 74.57; H, 4.50; N, 5.43. Found: C, 74.01; H, 4.29; N, 5.31.

2,6-{2-PhN=C(H)C6H4}2C6H3I (4.7)

4.7 was prepared in an analogous manner to 4.6. Starting materials of 4.5 (0.50 g, 1.2 mmol) and aniline (0.30 g, 3.2 mmol) were used, and 0.53 g pale yellow crystalline 4.7 (78 %) was obtained.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 8.21 (CH=NPh), 8.22 (CH=NPh), 6.94-6.96 (m), 7.06-7.11 (m),

13 1 7.19-7.38 (m), 7.47 (t, JHH = 7 Hz, 1H), 7.49-7.57 (m, 4H), 8.35-8.38 (m, 2 H). C { H} NMR

(CDCl3, 100 MHz): δ 158.0 (CH=NPh), 159.0 (CH=NPh), 106.2 (Ar(C)-I), 106.5 (Ar(C)-I),

120.9, 121.1, 126.1, 126.2, 127.0, 127.1, 127.9, 128.1, 128.8, 129.4, 129.9, 130.2, 130.4, 130.7,

130.9, 131.1, 133.8, 145.7, 145.8, 146.8, 146.9, 152.0, 152.7. Anal. Calcd for C32H23N2I: C,

68.34; H, 4.12; N, 4.98. Found: C, 68.30; H, 3.75; N, 4.83.

2,6-{2-XylN=C(H)C6H4}2C6H3I (4.8) (Xyl = 2,6-(CH3)2C6H3)

4.8 was prepared in an analogous manner to 4.6. Starting materials of 4.5 (1.00 g, 2.40 mmol)

117 and 2,6-dimethylaniline (0.88 g, 7.3 mmol) were used, and 1.35 g pale yellow crystalline 4.8

(90 %) was obtained.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 7.96 (CH=NXyl), 8.00 (CH=NXyl), 1.95 (CH3-), 2.13 (CH3-),

6.88-7.07 (m, 6H), 7.22-7.30 (m, 4H), 7.38-7.41 (m, 1H), 7.55-7.58 (m, 4H), 8.40-8.42 (m, 2 H).

13 1 C { H} NMR (CDCl3, 100 MHz): δ 160.5 (CH=NXyl), 161.0 (CH=NXyl), 18.6 (CH3-), 18.8

(CH3-), 106.4 (Ar(C)-I), 123.9, 126.7, 126.9, 127.1, 127.6, 127.5, 127.7, 128.3, 128.4, 128.8,

129.6, 129.8, 130.4, 131.0, 130.9, 131.1, 133.8, 133.9, 145.7, 145.8, 146.6, 146.8, 159.9, 151.4.

Anal. Calcd for C36H31N2I: C, 69.90; H, 5.05; N, 4.53. Found: C, 69.60; H, 4.80; N, 4.42.

2,6-{2-MesN=C(H)C6H4}2C6H3I (4.9) (Mes = 2,4,6-(CH3)3C6H2)

4.9 was prepared in an analogous manner to 4.6. Starting materials of 4.5 (1.00 g, 2.40 mmol) and 2,4,6-trimethylaniline (0.86 g, 6.4 mmol) were used, and 1.44 g pale yellow crystalline 4.9

(92 %) was obtained.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 7.95 (H=NMes), 7.97 (H=NMes), 1.92 (CH3-), 2.08 (CH3-), 2.27

(CH3-), 6.70 (s), 6.87 (s); 7.20-7.27 (m, 4H), 7.34-7.38 (m, 1H), 7.52-7.56 (m, 4H), 8.37-8.40 (m,

13 1 2 H). C { H} NMR (CDCl3, 100 MHz): δ 160.5 (CH=NMes), 161.1 (CH=NMes), 18.6, 18.8,

20.9, 21.1, 106.4 (Ar(C)-I), 126.6, 126.7, 127.2, 127.4, 127.7, 128.7, 128.9, 129.0, 129.6, 129.8,

130.4, 130.7, 130.9, 133.0, 133.6, 133.9, 134.0, 145.7, 145.8, 146.5, 146.7, 148.4, 149.0. Anal.

Calcd for C38H35N2I: C, 70.59; H, 5.46; N, 4.33. Found: C, 70.37; H, 5.23; N, 4.18.

2,6-{2-CyN=C(H)C6H4}2C6H3I (4.10) (Cy = cyclohexyl)

4.10 was prepared in an analogous manner to 4.6. Starting materials of 4.5 (2.00 g, 4.85

118 mmol) and cyclohexylamine (1.01 g, 10.2 mmol) were used, The resultant material (2.72 g, 97%) was in good quality as indicated by 1H NMR spectroscopy, and used as is.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-) 1H

NMR (CDCl3, 400 MHz): δ 1.21-1.36 (m, 6H), 1.51-1.70 (m, 10H), 1.79 (br, 4H), 2.94-3.04 (m,

2H), 7.19-7.22 (m, 2H), 7.25-7.27 (m, 2H), 7.43-7.48 (m, 5H), 8.03 (s, 1H, ArCH=N), 8.05 (s,

13 1H, ArCH=N), 8.10-8.14 (m, 2H). C NMR (CDCl3, 100 MHz): δ 24.8, 24.9, 25.0, 25.9, 34.5,

34.6, 70.1, 70.3, 106.38 (Ar(C)-I), 106.43 (Ar(C)-I), 126.8, 126.9, 127.7, 127.8, 129.6, 129.8,

129.9, 130.0, 130.1, 134.2, 134.4, 145.75, 145.80, 145.82, 146.0, 156.7 (CH=N), 157.0 (CH=N).

[2,6-{2-PhN=C(H)C6H4}2C6H3PdI] (4.11)

A mixture of 4.7 (0.10 g, 0.18 mmol) and Pd2(dba)3 (0.10 g, 0.11 mmol) was dissolved in 15 mL anhydrous benzene in a 20 mL vial, and stirred under N2 for 16 h. The precipitate that formed was filtered and washed with 5 mL of benzene. The solids were extracted with 30 mL of CHCl3.

Upon removal of the CHCl3, 0.069 g of pale yellow crystalline 4.11 was obtained (45%).

1 H NMR (CDCl3, 400 MHz): δ 8.44 (s, 2H, CH=NPh), 7.13-7.16 (m, 6H), 7.19-7.23 (m, 1H),

7.27-7.29 (m, 2H), 7.33-7.26 (m, 4H), 7.56-7.60 (m, 4H), 7.71-7.72 (m, 4H). 13C {1H} NMR

(CDCl3, 100 MHz): δ 165.5 (CH=NPh), 150.8 (Ar(C)-Pd), 123.2, 125.6, 127.6, 128.5, 128.7,

128.8, 130.2, 131.1, 131.4, 132.7, 141.1, 141.8, 150.2. Anal. Calcd for C32H23N2IPd·CHCl3: C,

50.28; H, 3.07; N, 3.55. Found: C, 50.24; H, 2.58; N, 3.40.

[2,6-{2-XylN=C(H)C6H4}2C6H3PdI] (4.12)

A mixture of 4.8 (0.20 g, 0.32 mmol) and Pd2(dba)3 (0.18 g, 0.19 mmol) were dissolved in 15 mL anhydrous benzene in a 20 mL vial, and stirred at room temperature under N2 for 16 h.

Using the same procedure used to isolate 8, 0.15 g pale yellow crystalline product of 4.12 was

119 obtained (65 %).

1 H NMR (CDCl3, 600 MHz): δ 8.13 (s, 2H, CH=NPh); 2.05 (br, CH3, 6H), 2.46 (br, CH3, 6H),

6.82 (br, 2H), 6.95 (t, JHH = 8Hz, 2 H), 7.00 (br, 2H), 7.24-7.26 (m, 3H), 7.44 (d, JHH = 8Hz, 2H),

13 1 7.54-7.56 (m, 2H), 7.65 (d, JHH = 8Hz, 2H), 7.68-7.7 (m, 2H). C { H} NMR (CDCl3, 150

MHz): δ 172.1 (s, CH=NXly), 149.4 (Ar(C)-Pd), 21.6 (br, CH3), 22.0 (br, CH3), 125.3, 127.1,

127.2, 128.2 (br), 128.7, 128.8, 130.2, 131.1, 131.4, 132.7, 141.1, 141.8, 150.2. Anal. Calcd for

C36H31N2IPd: C, 59.64; H, 4.31; N, 3.86. Found: C, 59.40; H, 4.00; N, 3.58.

[2,6-{2-MesN=C(H)C6H4}2C6H3PdI] (4.13)

A mixture of 4.9 (0.20 g, 0.31 mmol) and Pd2(dba)3 (0.17 g, 0.18 mmol) were dissolved in 15 mL anhydrous benzene in a 20 mL vial, and stirred at room temperature under N2 for 16 h.

Using the same work up procedure as 4.11, 0.16 g yellow crystalline product of 4.13 was obtained (69 %).

1 H NMR (CDCl3, 600 MHz): δ 8.10 (s, 2H, CH=NPh); 2.01 (br, CH3, 6H), 2.15 (s, CH3, 6H),

2.41 (br, CH3, 6H), 6.62 (br, 2H), 6.81 (br, 2H), 7.23-7.26 (m, 3H), 7.42 (d, JHH = 8Hz, 2H),

13 1 7.52-7.55 (m, 2H), 7.63 (d, JHH=7Hz, 2H), 7.67 (t, JHH = 7Hz, 2H). C { H} NMR (CDCl3,

150 MHz): δ 171.7 (s, CH=NMes), 149.60 (Ar(C)-Pd), 20.8 (s, 21.5 CH3), (br, CH3), 21.8 (br,

CH3), 125.2, 127.1, 128.9 (br), 129.8, 130.1 (br), 130.4, 130.7 (br), 131.0 (br), 131.1, 131.6,

133.2, 136.5, 141.2, 143.3, 149.63. Anal. Calcd for C38H35N2IPd: C, 60.61; H, 4.68; N, 3.72.

Found: C, 60.26; H, 4.41; N, 3.62.

[2,6-{2-CyN=C(H)C6H4}2C6H3PdI] (4.14)

A mixture of 4.7 (0.31 g, 0.54 mmol) and Pd2(dba)3 (0.30 g, 0.33 mmol) was dissolved in 15 mL anhydrous benzene in a 20 mL vial, and stirred under N2 for 16 h. The precipitate that formed

120 was filtered and washed with 5 mL of benzene. The solids were extracted with 20 mL of CH2Cl2.

Upon removal of the CH2Cl2, 0.21 g of pale yellow crystalline 8 was obtained (59 %).

1 H NMR (CDCl3, 400 MHz): δ 0.80-0.95 (m, 4H), 1.07-1.30 (m, 6H), 1.42-1.50 (m, 4H),

1.61-1.65 (m, 2H), 1.84 (d, JHH = 11.6 Hz, 2H), 3.29 (d, JHH = 12.8 Hz, 2H), 3.91-3.97 (m, 2H),

7.14-7.15 (m, 3H), 7.39-7.41 (m, 2H), 7.45-7.49 (m, 4H), 7.52-7.56 (m, 2H), 8.16 (d, JHH = 1.6

13 1 Hz, 2H, CH=N). C { H} NMR (CDCl3, 100 MHz): δ 24.9, 25.3, 25.6, 32.1, 36.2, 69.7

(Cy(C)-N), 125.0, 127.1, 127.8, 129.6, 131.3, 133.0, 141.1, 141.7, 151.3 (Ar(C)-I), 162.4

(CH=N).

121 NMR Spectra

1 Figure 4.9. H NMR spectrum of 4b (CDCl3, 400 MHz).

1 Figure 4.10. H NMR spectrum of 4b, aromatic region (CDCl3, 400 MHz).

122

13 Figure 4.11. C NMR spectrum of 4b (CDCl3, 100 MHz).

13 Figure 4.12. C NMR spectrum of 4b, aromatic region (CDCl3, 100 MHz).

123

1 Figure 4.13. H NMR spectrum of 4.5 (CDCl3, 400 MHz).

1 Figure 4.14. H NMR spectrum of 4.5, aromatic region (CDCl3, 400 MHz).

124

13 Figure 4.15. C NMR spectrum of 4.5 (CDCl3, 100 MHz).

13 Figure 4.16. C NMR spectrum of 4.5, aromatic region (CDCl3, 100 MHz).

125

1 Figure 4.17. H NMR spectrum of 4.7 (CDCl3, 400 MHz).

13 Figure 4.18. C NMR spectrum of 4.7 (CDCl3, 100 MHz).

126

1 Figure 4.19. H NMR spectrum of 4.8 (CDCl3, 400 MHz).

1 Figure 4.20. H NMR spectrum of 4.8, aromatic region (CDCl3, 400 MHz).

127

13 Figure 4.21. C NMR spectrum of 4.8 (CDCl3, 100 MHz).

13 Figure 4.22. C NMR spectrum of 4.8, aromatic region (CDCl3, 100 MHz).

128

1 Figure 4.23. H NMR spectrum of 4.9 (CDCl3, 400 MHz).

1 Figure 4.24. H NMR spectrum of 4.9, aromatic region (CDCl3, 400 MHz).

129

13 Figure 4.25. C NMR spectrum of 4.9 (CDCl3, 100 MHz).

13 Figure 4.26. C NMR spectrum of 4.9, aromatic region (CDCl3, 100 MHz).

130

1 Figure 4.27. H NMR spectrum of 4.10 (CDCl3, 400 MHz).

13 Figure 4.28. C NMR spectrum of 4.10 (CDCl3, 100 MHz).

131

13 Figure 4.29. C NMR spectrum of 4.10, alkyl region (CDCl3, 100 MHz).

13 Figure 4.30. C NMR spectrum of 4.10, aromatic region (CDCl3, 100 MHz).

132

1 Figure 4.31. H NMR spectrum of 4.11 (CDCl3, 400 MHz).

1 Figure 4.32. H NMR spectrum of 4.11, aromatic region (CDCl3, 400 MHz).

133

13 Figure 4.33. C NMR spectrum of 4.11 (CDCl3, 100 MHz).

13 Figure 4.34. C NMR spectrum of 4.11, aromatic region (CDCl3, 100 MHz).

134

1 Figure 4.35. H NMR spectrum of 4.12 (CDCl3, 600 MHz).

1 Figure 4.36. H NMR spectrum of 4.12, aromatic region (CDCl3, 600 MHz).

135

13 Figure 4.37. C NMR spectrum of 4.12 (CDCl3, 100 MHz).

13 Figure 4.38. C NMR spectrum of 4.12, aromatic region (CDCl3, 100 MHz).

136

1 Figure 4.39. H NMR spectrum of 4.13 (CDCl3, 400 MHz).

1 Figure 4.40. H NMR spectrum of 4.13, aromatic region (CDCl3, 400 MHz).

137

13 Figure 4.41. C NMR spectrum of 4.13 (CDCl3, 100 MHz).

13 Figure 4.42. C NMR spectrum of 4.13, aromatic region (CDCl3, 100 MHz).

138

1 Figure 4.43. H NMR spectrum of 4.14 (CDCl3, 400 MHz).

1 Figure 4.44. H NMR spectrum of 4.14, aromatic region (CDCl3, 400 MHz).

139

13 Figure 4.45. C NMR spectrum of 4.14 (CDCl3, 100 MHz).

13 Figure 4.46. C NMR spectrum of 4.14, aromatic region (CDCl3, 100 MHz).

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143 Chapter 5. NCN Diamine Pincer Ligands and Complexes: Synthesis and Structural Studies

5.1 Introduction

- NCN diamine pincer ligand [2,6-(Me2NCH2)2C6H3] (5.1) (Chart 5.1, left) and its metal complexes (5.2) (Chart 5.1, right) have been widely studied since its introduction by van Koten et al. at 1978.1,2 Many metal complexes constructed with such ligand platform have been reported, among them Ni(II), Pd(II) and Pt(II) complexes are extensively explored.3-10 These pincer complexes are investigated as catalysts for carbon-carbon bond formation,11 transfer hydrogenation12, and gas sensor13-15 as well.

N N

R R M X

N N

5.1 5.2

Chart 5.1. NCN pincer ligand (left) and its complex (right).

Although the phosphine analogues show more reactivity in many catalytic reactions, NCN pincer ligands offer more stability towards moisture and air. Such stability makes it more practical to modify the NCN pincer platform by changing different functional groups within their multiple anchoring points.16,17 Therefore its catalytic properties can be tuned by changing the electronic property of the metal center or constructing steric building block to gain stereoselectivity. There are some examples of chiral pincer ligands and complexes that have been reported. However these reported examples are limited to the modification of the methylene groups in the two arms (5.3)18 of the pincer ligands or the substituents on the donor atoms (5.4, 5.5)19,20 (Chart 5.2).

144 R H R Ph N R N N N

Pt X Ni X Pd X R N N N R Ph R R H

5.3 5.4 5.5

Chart 5.2. Examples of chiral NCN pincer complexes. 18-20

All of the above examples contain two five-membered chelate rings, which slightly twisted the central phenyl ring.2 However, this nearly flat nature of this type of complex can not prevent the interconversion of its atropisomers. To generate rigid C2 symmetric, and chiral complexes is the main goal. In order to maintain the configuration of each atropisomers, a rigid m-terphenyl backbone is introduced. Based on this strategy, two kinds of pincer complexes (5.6, 5.7)21,22

(Chart 5.3) have been synthesized and discussed in the previous chapters, and no evidence has indicated interconversion of atropisomers even at elevated temperature. In this chapter detailed synthesis and characterization of diamine pincer complexes bearing m-terphenyl scaffold are discussed.

R R R

P N

Pd Pd

I P Br N

R R R t (R = Ph, Bu, Cy) (R = Ph, 2,6-Xylyl, Mesityl, Cy)

5.6 5.7

Chart 5.3. Previously reported m-terphenyl based PCP and NCN pincer complexes.

145 5.2 Results and Discussion

5.2.1 Synthesis of NCN Pincer Ligand and Complexes.

The key intermediate 2,6-(2-CHO-C6H4)2C6H3I (5.8) was synthesized according to the method

21,22 reported previously. 2,6(2-NMe2-C6H4)2C6H3I (5.9) was synthesized from 5.8 by modified literature method.23 According to the previous reports, these m-terphenyl precursors, such as compound 5.8, contain two stable conformations within NMR time scale. During the synthesis of 5.9, viscous oil was obtained due to the existence of both syn- and anti- isomers. However, nice crystalline solid of 5.9 was obtained after being crystallized from diethyl ether or 2-propanol under -5 °C. Both 1H and 13C NMR spectroscopy of 5.9 suggest that the resultant solid contains only one conformation syn- or anti-, since only one resonance for the methyl groups in the methyl region (2.16 ppm in 1H NMR and 46.2 ppm in 13C NMR). Further characterization by

X-ray crystallography suggested that only syn- isomer of 5.9 was formed during crystallization.

O O Me2N NMe2

i 1. Et3N, Ti(O Pr)4 + Me2NH HCl I 2. NaBH4 I

5.8 5.9

Scheme 5.1. Synthesis of diamine NCN pincer ligand.

Although the crystalline solid of ligand 5.9 contains only syn- isomer, after being mixed with

Pd2(dba)3 in THF pincer complex 5.10 is thus produced in good yield (73%). This fact further proved that those syn- and anti- isomers of m-terphenyl ligand precursors, if not fast, are interconvertible in solution. It is worth mentioning that no pincer complex 5.10 was produced when using benzene as solvent which was successfully used for the related diphosphine and diimine pincers. The reaction rate is somewhat slow in THF, and excess (2 equiv.) amount of

146 Pd2(dba)3 is needed to completely consume ligand 5.9.

H3C CH3 N

Pd2(dba)3 M 5.9 or Ni(COD) I 2 N

H3C CH3 5.10, M = Pd 5.12, M = Ni

Scheme 5.2. Synthesis of diamine NCN pincer complexes.

5.2.2 X-ray Crystallography Studies.

Single crystals of 5.9 were grown by slow evaporation of 2-propanol solution of 5.9 at -5 °C.

As shown in Figure 5.1, the structure of the diamine pincer ligand 5.9 shows syn- conformation, instead of anti- as expected. Either of the two side phenyl rings is almost vertical to the central phenyl ring, of which the dihedral angles are 87.8° and 82.5°, respectively. The bond angles of

N1-C19-C8 112.7(2)°, and N2-C20-C14 113.9(2)° almost remain the same when it forms the pincer complex 5.10, of which the bond angles of N1-C19-C8 and N2-C20-C14 are 112.5(4)° and 112.9(4)°, respectively (Table 5.1). For the m-xylyl based NCN pincer systems the corresponding bond angles of ligands change from ~113°to ~108° when forming the complexes.24,25 This may indicate that there is less ring strain in these pincer complexes bearing m-terphenyl scaffold than those of m-xylyl based systems.

147

Figure 5.1. An ORTEP drawing (40% probability thermal ellipsoids) of 5.9 with atom labeling scheme. Hydrogen atoms have been omitted for clarity. Selected bond lengths (Å) and angles

(o): C1-I1, 2.102(3); N1-C19, 1.464(3); N1-C21, 1.458(4); N1-C22, 1.459(4); N2-C23, 1.460(4);

N2-C24, 1.458(4). N1-C19-C8, 112.7(2); N2-C20-C14, 113.9(2); C8-C7-C6-C1, 89.5;

C14-C13-C2-C1, 83.7.

Single crystals of 5.10 were grown by vapor diffusion of hexane into CHCl3 solution of 5.10 at room temperature. There are four independent molecules in the asymmetric unit; only one is shown in Figure 5.2 and the selected bond lengths and angles for those four molecules are shown in Table 5.1. As shown in Figure 5.2, the geometry of the center palladium (II) is slightly distorted square planner coordinated by an anionic terdentate NCN pincer ligand and an iodine anion. The distance of C1-Pd1 1.995(5) Å is slightly larger than those of m-xylyl based pincer

25 complexes, such as [2,6-(Me2NCH2)2C6H3]PdI·2I2 (1.920(8) Å), [2,6-(Me2NCH2)2C6H3]

Pd(OPh) (1.910(2) Å).26 When compared the C1-Pd1 bond lengths of another two

27 para-substituted examples [4-NMe2-2,6-(Me2NCH2)2C6H3]PdBr (1.921(2) Å) and [4-NO2-2,6-

148 6 (Me2NCH2)2C6H3] PdBr (1.913(2) Å) , electronic properties of the C1 atom do not affect the

C1-Pd1 bond length that much. The bond angle of N1-Pd1-N2 170.98(16), notably, are closer to linear than those reported6,25-27 m-xylyl based NCN diamine pincer complexes, which range from 161° to 163°. The reasons for these differences could be rationalized from the increased ring size of chelating rings (from 5 to 7), which releases the ring strain. The C1-Pd1-I1 bond angle of 160.36(15)°, however, is more distorted from coordination plane constructed by the terdentate ligand and the palladium center than the above examples6,25-27 which range from 172° to 179°. The two amine N donors are coordinating to the palladium (II) center from either side of the center benzene ring of the m-phenyl backbone, which produces a twist angle of 74°. The architecture of the m-terphenyl contributes those large twist angles, as well as the rigidity of this type of pincer complexes and prevents and interconversion of its atropisomers.21,22

Figure 5.2. ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.10.

Hydrogen atoms are omitted for clarity, and only one of the four independent molecules in the asymmetric unit is shown.

149

Table 5.1. Selected bond lengths (Å) and angles (o) of complex 5.10 (four independent molecules in the asymmetric unit).

5.10a 5.10b 5.10c 5.10d Pd1-C1 1.995(4) 1.995(4) 1.998(4) 1.994(4) Pd1-I1 2.8018(4) 2.8170(4) 2.8238(4) 2.8199(4) Pd1-N1 2.121(3) 2.126(3) 2.158(3) 2.162(3) Pd1-N2 2.167(3) 2.167(3) 2.118(3) 2.125(3) C1-Pd1-N1 88.76(14) 89.04(14) 89.26(13) 86.55(13) C1-Pd1-N2 88.75(14) 86.36(14) 86.64(14) 88.52(13) N1-Pd-I1 91.72(9) 91.16(9) 91.22(9) 95.11(9) N2-Pd-I1 94.98(9) 96.31(9) 95.73(9) 92.18(9) N1-C19-C8 112.9(3) 114.0(3) 114.0(3) 111.9(3) N2-C20-C14 112.0(3) 112.7(3) 112.0(3) 112.9(3) C1-Pd1-I1 160.72(12) 159.27(11) 160.05(11) 161.50(11) N1-Pd1-N2 171.31(13) 169.93(13) 170.05(13) 170.42(13) Twist angle 74.2 72.8 73.4 74.2

Crystals grown by vapor diffusion of hexane into THF solution of 5.10 at -5 ºC were found to be of two types. The majority of those crystals were light yellow in color, accompanied by a very small amount of crystals that are pale orange color. The structure for the light yellow crystals came out similar to crystals grown by vapor diffusion of hexane into CHCl3 solution, which is also light yellow in color. The crystal structure of the pale orange ‘impurity’, compound 5.11, revealed a trimer of NCN pincer complexes connected by a carbonate group,

- o with I3 as counter anion (Figure 5.3). The selected bond lengths (Å) and bond angles ( ) are

150 listed in Table 5.2.

Figure 5.3. ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.11.

- Solvent molecules, counter anion (I3 ) and hydrogen atoms are omitted for clarity.

151 Table 5.2. Selected bond lengths (Å) and angles (o) of complex 5.11.

Pd1-C1 1.987(6) Pd1b-C1b 1.987(6) Pd1c-C1c 1.991(6) Pd1-O1a 2.111(4) Pd1b-O1b 2.119(4) Pd1c-O1c 2.117(4) Pd1-N1 2.135(6) Pd1b-N1b 2.127(5) Pd1c-N1c 2.118(5) Pd1-N2 2.130(6) Pd1b-N2b 2.132(5) Pd1c-N2c 2.146(5) C1-Pd1-O1a 174.5(2) C1b-Pd1b-O1b 171.1(2) C1c-Pd1c-O1c 172.2(2) N1-Pd1-N2 178.0(2) N1b-Pd1b-N2b 178.3(2) N1c-Pd1c-N2c 176.8(2)

Single crystal of 5.12 was grown by slow evaporation of THF solution of 5.12 at room temperature under nitrogen atmosphere. It shows a similar structure (Figure 5.3) as the corresponding palladium complex 5.10. Selected bond lengths and bond angles are listed at

Table 5.3. The Ni(II) center has a slightly more distorted square planner geometry than the

Pd(II) center in complex 5.10, with a more bended N1-Ni-N2 angle of 164.6°. The bond length of C1-Ni1, 1.904(4) Å, is slightly larger than the m-xylyl based example

[4-SiMe3-2,6-(Me2NCH2)2C6H3]NiI (1.816 Å), which is the similar case when comparing complex 5.10 with the m-xylyl based pincer complexes.

Figure 5.4. ORTEP drawing (40% probability ellipsoids) of the molecular structure of 5.12. Hydrogen atoms are omitted for clarity.

152 Table 5.3. Selected bond lengths (Å) and angles (o) of complex 5.12

Ni1-C1 1.904(4) N1-Ni-I1 95.2(1) Ni1-I1 2.6903(6) N2-Ni-I1 91.9(1) Ni-N1 2.030(3) N1-C19-C8 111.5(3) Ni-N2 2.002(3) N2-C20-C14 114.5(3) C1-Ni1-N1 88. 8(2) C1-Ni1-I1 151.6(1) C1-Ni1-N2 91.6(2) N1-Ni1-N2 164.6(1) Twist angle 74.2

5.2.3 NMR Spectroscopy Studies.

The conformation of ligand precursor 5.9 has been confirmed as syn- isomer. In the NMR spectroscopy studies of 5.9, there is one singlet at 2.16 ppm assigned to the methyl groups, and the resonances of the methylene protons appear as two doubles at 3.11 ppm and 3.31 ppm, respectively, with coupling constants of 13.6 Hz. After forming the pincer complex 5.10, the resonances of the methylene protons have shifted to 2.64 ppm and 3.03 ppm with coupling constants of 12 Hz. The methylene protons H20A and H19B are pointing at either side of the center benzene ring with a relatively close distance about 3.0 Å (Figure 5.5). Due to the ring current effect, the more upfield shifted resonance 2.64 ppm is thus assigned to H20A/H19B.

153

Figure 5.5. Illustration of the proximity of protons to the central benzene ring in complex 5.10.

Meanwhile, the corresponding methyl signal has changed to two different resonances at 2.46 ppm and 3.05 ppm. Such a big difference may be caused by the proximity of one of the methyl groups (C22 and C23) to the central benzene ring, and the other methyl groups (C21 and C24) to the iodine atom. The more upfield shifted resonance 2.46 ppm is assigned to H22 and H23 due to the ring current effect, while the resonance at 3.05 ppm is assigned to H21 and H24 which are closer to the iodine atom. The chemical shifts for the methylene and methyl groups in the m-xylyl based NCN pincer complex [2,6-(Me2NCH2)2C6H3]PdI are 4.00 ppm and 3.03 ppm, respectively, as two singlets.28 These chemical shifts are not affected much by the coordination of halogen atoms (Table 5.4).

154 Table 5.4. 1H NMR data for m-xylyl based NCN pincer complexes and complex 5.10.

complex δCH2 (JHH/Hz) δCH3 ref 28 [2,6-(Me2NCH2)2C6H3]PdCl 3.98 2.93 28 [2,6-(Me2NCH2)2C6H3]PdBr 4.00 2.97 28 [2,6-(Me2NCH2)2C6H3]PdI 4.00 3.03 t 29 [4- BuSi(Me)2O-2,6-(Me2NCH2)2C6H3]PdI 3.94 3.01 27 [4-NMe2-2,6-(Me2NCH2)2C6H3]PdBr 3.95 2.96 27 [4-NO2-2,6-(Me2NCH2)2C6H3]PdBr 4.05 2.99 28 [2,6-(Me2NCH2)2C6H3Pd(H2O) ]BF4 4.17 2.87 8 [{[2,6-(Me2NCH2)2C6H3]Pd}2(μ-Cl)]BF4 4.13 2.83 5.10 2.64(12), 3.03(12) 2.46, 3.05(br)

Comparing the sharp resonance of 2.46 ppm, however, the resonance at 3.05 ppm is broad.

In the previously reported PCP diphosphine and NCN diimine pincer systems, broad signals at

NMR spectroscopy were observed at room temperature for the complexes, [2,6-(2- t Bu2PCH2C6H4)2C6H3PdBr] and [2,6-{2-ArN=C(H)C6H4}2C6H3PdI] (Ar = 2,6-xylyl or mesityl), with bulky groups attached to the donor atoms. The variable temperature NMR experiments suggested the presence of hindered rotation about the P-tBu or N-Ar bond. However, there is no bulky group surrounding the nitrogen donor atoms of complex 5.10, and hence it is unlikely to have a hindered rotation about the N-CH3 bond.

To elucidate such resonance broadening phenomenon, variable temperature NMR experiments have been carried out for complex 5.10 (Figure 5.6). When the temperature decreases the resonance at 3.05 ppm gets sharpened, while broader peak is observed when the temperature increases. If the hindered methyl rotation persists, its linewidth could have decreased with increasing temperature.

155

Figure 5.6. Variable temperature NMR spectra of complex 5.10 (CDCl3, 600 MHz).

156 To further investigate such phenomenon, variable concentration NMR experiments were performed for 5.10 (Figure 5.7). During these experiments, the temperature was fixed at 25 °C and the sample concentration was changed from 54 mmol/L to 0.79 mmol/L. Broadened resonance at 3.05 ppm was observed for concentrated samples. While decreasing the sample concentration, the line width of the resonance at 3.05 ppm is getting closer to that of the resonance at 2.46 ppm.

Figure 5.7. Variable concentration NMR spectra of complex 5.10 (CDCl3, 600 MHz).

157 These results suggest a possible equilibrium in the solution (Scheme 5.3). At lower temperature or lower concentration, there is less interaction of complex 5.10, hence, less dimeric species. In the other hand, at higher temperature of higher concentration, there exist more dimeric species which contributes the line broadening. Although dimerization of m-xylyl based

NCN pincer complexes has been reported by van Koten and coworkers,8 further investigation of these new pincer systems containing m-terphenyl are undergoing.

N N N

2 Pd I Pd I Pd I

N N N

Scheme 5.3. Proposed equilibrium of 5.10 in solution.

158 5.3 Conclusion

In summary, new diamine NCN pincer ligands and complexes bearing m-terphenyl scaffolds have been synthesized using the similar approach as the previously reported diphosphine PCP and diimine NCN pincer systems. Structural studies of these diamine NCN pincer complexes reveal a similar C2 symmetric environment and large twist angles as well, which is essential to maintain their rigidity within the m-terphenyl frameworks. Line broadening for one of the methyls of complex 5.10 is observed at elevated temperature during NMR spectroscopy studies.

A particular rare trimer structure has been discovered during the synthesis of complex 5.10.

Further investigations are needed to better understand the structure properties and their reactivities.

159 5.4 Experimental

General Procedures and Materials

Experiments involving manipulation of air- and water sensitive materials were carried out using Schlenk techniques or in a glove box under nitrogen. Certified A.C.S. grade solvents

(THF, CH2Cl2, hexanes, ethanol and methanol) from Fisher were used as received. Anhydrous solvents THF, hexanes and diethyl ether were distilled from Na/benzophenone prior to use.

The NMR spectroscopy measurements were recorded on a Varian Inova 400 or 600 MHz spectrometers. Chemical shifts were referenced to residual solvent signals (1H, 13C NMR).

Elemental analyses were performed by Quantitative Technologies, Inc. NJ.

22 2,6-{2-C(H)OCH2C6H4}2C6H3I (5.8) was synthesized by literature methods.

2,6-(2-Me2NCH2C6H4)2C6H3I (5.9)

To a solution of 5.8 (2.00 g, 4.85 mmol) in 15 mL THF in a 100 mL round bottom flask, a

i mixture of Ti(O Pr)4 (5.71 g, 20.1 mmol), Me2NH•HCl (1.61 g, 19.7 mmol) and NEt3 (1.23 g,

12.2 mmol) in 20 mL EtOH was added. This reaction mixture was stirred overnight at room temperature under N2. Then NaBH4 (0.556 g, 14.7 mmol) was added. After being stirred for an additional 12 h, the reaction mixture was quenched by pouring into 30 mL of 2 M aqueous ammonium hydroxide and then filtered. The remaining solid was rinsed with 50 mL CH2Cl2, and the filtrate was extracted by CH2Cl2 (2 x 50 mL). The solvent was removed in vacuo.

The remaining sticky compound was dissolved in ether and filtered. The ether solution was kept in refrigerator (-5 Cº) overnight. Colorless crystalline solid of 5.9 was obtained (0.75 g,

33%). Anal. Calcd. for C24H27N2I: C, 61.28; H, 5.79; N, 5.96. Found: C, 61.14; H, 5.64; N,

5.79.

1 H NMR (CDCl3, 400 MHz): δ 2.16 (s, 12H, CH3), 3.14 (d, JHH = 13.6 Hz, 2H, -CH2-), 3.31 (d

160 JHH = 13.6 Hz, 2H, -CH2-), 7.14-7.18 (m, 4H), 7.30-7.34 (m, 2H), 7.38-7.43 (m, 3H), 7.58-7.60

13 1 (m, 2H). C { H} NMR (CDCl3, 100 MHz): δ 46.2 (CH3), 61.5 (-CH2-), 107.3 (Ar(C)-I),

126.7, 127.5, 128.2, 128.7, 129.1, 129.5, 137.0, 145.3, 146.9.

[2,6-(2-Me2NCH2C6H4)2C6H3PdI] (5.10)

A mixture of 5.9 (0.20 g, 0.43 mmol) and Pd2(dba)3 (0.23 g, 0.25 mmol) were dissolved into

15 mL anhydrous THF and stirred overnight at room temperature under N2. The reaction was monitored by 1H NMR. After overnight stirring only half of the ligand 5.9 reacted. Another portion of Pd2(dba)3 (0.46 g, 0.50 mmol) was added. After an additional 16 h of stirring, the resultant solution was filtered and the solvent was removed in vacuo. The product was purified by flash column chromatography using methanol/hexanes (1:20 v/v) as eluent. Yellow crystalline solid of 5.10 (0.18 g, 73%) was obtained. Analytical pure product was obtained via recrystallization from CH2Cl2/hexanes. Anal. Calcd. for C24H27N2IPd: C, 49.98; H, 4.72; N,

4.86. Found: C, 49.62; H, 4.57; N, 4.82.

1 H NMR (CDCl3, 400 MHz): δ 2.46 (s, 6H, -CH3), 2.64 (d, JHH = 11.6 Hz, 2H, -CH2-), 2.03 (d,

JHH = 12 Hz, 2H, -CH2-), 3.04 (br 6H, -CH3), 6.99 (d, JHH = 7.2 Hz, 2H), 7.16 (t, JHH = 7.2 Hz,

13 1 2H), 7.30 (d, JHH = 7.6 Hz, 2H), 7.42-7.46 (m, 2H), 7.56-7.63 (m, 4H). C { H} NMR (CDCl3,

100 MHz): δ 54.0 (-CH3), 61.5 (br, -CH3), 67.3 (-CH2-), 125.0, 126.7, 127.4, 127.6, 129.5, 130.4,

134.5, 143.4, 148.0 (Ar(C)-Pd).

[2,6-(2-Me2NCH2C6H4)2C6H3NiI] (5.12)

To a solution of Ni(COD)2 (0.070 g, 0.25 mmol) in 15 mL anhydrous THF which was chilled to -78 °C using acetone/dry ice bath, a solution of 5.9 (0.10 g, 0.21 mmol) in 15 mL anhydrous

THF was added dropwise via cannula. The acetone/dry-ice cold bath was removed after 20 min

161 of stirring under N2 atmosphere. The reaction mixture was then warmed up to room temperature slowly. The color the solution changed after 45 min from light yellow to light green, then to light blue, and finally brown color. The color changing process was lasted for about 10 min. After another 2 hour of stirring under room temperature, the reaction mixture was filtered and the filtrate was collected. (About 1 mL of solution was used to set up crystallization) Then the solvent was removed in vacuo. The remaining brown solid was washed with anhydrous hexanes to remove cyclooctadiene, followed by the washing with anhydrous diethyl ether to remove the unreacted diamine ligand. The resulting brown solid was dissolved in THF and filtered. However its solubility in THF was found become much lower.

After removal of the solvent, 50 mg brown solid was obtained. Since its very low solubility in

CDCl3 or CD2Cl2, no NMR spectrum was recorded. Its structure, however, has been determined by X-ray crystallography.

162 NMR Spectra:

1 Figure 5.8. H NMR spectrum for ligand 5.9 (CDCl3, 400 MHz).

163

13 Figure 5.9. C NMR of ligand 5.9 (CDCl3, 100 MHz).

13 Figure 5.10. C NMR of ligand 5.9, aromatic region (CDCl3, 100 MHz).

164

1 Figure 5.11. H NMR spectrum for complex 5.10 (CDCl3, 400 MHz).

13 Figure 5.12. C NMR of complex 5.10 (CDCl3, 100 MHz).

165

13 Figure 5.13. C NMR of complex 5.10, aromatic region (CDCl3, 100 MHz).

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(24) Back, S.; Albrecht, M.; Spek, A. L.; Rheinwald, G.; Lang, H.; van Koten, G.

Organometallics 2001, 20, 1024.

(25) Mills, A. M.; van Beek, J. A. M.; van Koten, G.; Spek, A. L. Acta Crystallogr. Sect. C-Cryst.

Struct. Commun. 2002, 58, m304.

168 (26) Alsters, P. L.; Baesjou, P. J.; Janssen, M. D.; Kooijman, H.; Sichererroetman, A.; Spek, A. L.;

Vankoten, G. Organometallics 1992, 11, 4124.

(27) Dijkstra, H. P.; Slagt, M. Q.; McDonald, A.; Kruithof, C. A.; Kreiter, R.; Mills, A. M.; Lutz,

M.; Spek, A. L.; Klopper, W.; van Klink, G. P. M.; van Koten, G. Eur. J. Inorg. Chem. 2003, 830.

(28) Grove, D. M.; Vankoten, G.; Louwen, J. N.; Noltes, J. G.; Spek, A. L.; Ubbels, H. J. C. J. Am.

Chem. Soc. 1982, 104, 6609.

(29) Dijkstra, H. P.; Kruithof, C. A.; Ronde, N.; van de Coevering, R.; Ramon, D. J.; Vogt, D.; van Klink, G. P. M.; van Koten, G. J. Org. Chem. 2003, 68, 675.

169 Chapter 6. Efforts towards Resolution of Chiral Pincer Complexes

6.1 Introduction

Pincer complexes have shown excellent applications in many catalytic reactions, such as Heck reactions1-5, transfer hydrogenation6 and catalytic dehydrogenation of alkanes.7-11 The introduction of a chiral center into the pincer systems could be developed as a power tool in the field of asymmetric catalytic synthesis. However, only a few examples have been reported.

These reported chiral pincer complexes are mostly constructed with the ‘traditional’ m-xylyl based pincer backbone, either by modification of methylene groups (6.112) or donor atoms (6.213) to afford a chiral center (Chart 6.1). Some of these chiral complexes (6.112, 6.314 and 6.415) have been used to catalyze the adol reactions of methylisocyanoacetate and aldehydes, and have shown good enantioselectivities.12,14,15

tBu PPh P 2 Ph Pd Cl Pd Cl Ph PPh2 P tBu 6.1 6.2 H R Ph N R O BF4 N N

Pd X Pd OH2

N N Ph N R O H R 6.3 6.4 Chart 6.1. Examples of chiral m-xylyl based pincer complexes.12-15

170 An alternative way to introduce chirality into the pincer system is to generate C2 symmetric environment. Some researchers16-18 have reported several examples of 3-D pincer complexes

(Chart 6.2) other than the planar m-xylyl system. Although complex 6.5 displayed a relatively large twist angle of 49°, facile interconversion between its two possible atropisomers, however, can yield effective non-chiral planar geometries, even in very low temperature, e.g. -60 °C.16

The interconversion of atropisomers of complex 6.6 was observed when heated to 77 °C monitoring by 1H NMR.17 The introduction of alkane groups in the methylene positions of complex 6.7 has greatly increased the rigidity of each atropisomers.18 Nevertheless no optically pure material has been isolated for complex 6.7.18

2 2BF 4 H C C8H17 NN 17 8 N N N N Ph2P Pd PPh2 Pd N Pd N Py N Br N N Cl N

6.5 6.6 6.7 Chart 6.2. Examples of pincer complexes having twisted structures.16-18

In the previous chapters, novel pincer complexes bearing m-terphenyl scaffolds have been introduced, which include PCP diphosphine and NCN diimine and diamine pincer complexes.

The m-terphenyl pincer systems containing the C2 symmetric environment have shown great rigidity even at elevated temperature, making these pincer complexes chiral. Since the success of imparting m-terphenyl scaffolds to these PCP and NCN pincer complexes, it was thus of immediate concern to resolve the enantiomers, and investigate the catalytic activity of the resultant optically pure materials. In this chapter, preliminary results of resolving racemic PCP

171 pincer complexes containing m-terphenyl scaffolds are presented. Furthermore two enantiomerically pure NCN diimine palladium pincer complexes are isolated and characterized.

6.2 Results and Discussion

One of the methods to achieve optical resolution of these chiral pincer complexes is to produce diastereomers. The halogen atom attach to the metal center is labile and ready to be substituted by a chiral group, such as a chiral amine, to afford diastereomers. Due to the different physical properties of the diastereomers, they can be separated by fractional crystallization of flash chromatography.

Ph Ph Ph Ph P P

Pd Pd H BF H2N 4 Br H P P H2N Ph Ph Ph Ph AgBF4 + CHCl Ph Ph 6.10a Ph Ph 3 P P

Pd Pd BF4 NH2 Br P P H Ph Ph Ph Ph

6.8 6.9 6.10b Scheme 6.1. Reaction of PCP pincer complex with (S)-α –phenylethylamine.

Different chiral amines, such as (S)-α–phenylethylamine (Scheme 1) and (S)-

α–tert-butylethylamine (Scheme 2) have been applied to resolve racemic pincer complex

31 [2,6-(2-CH2PPh2C6H4)2C6H3PdBr] (6.8). The reactions were monitored by P NMR. Due to the different properties of 6.10a and 6.10b, their chemical shifts are distinguishable, which are

25.5 ppm and 25.8 ppm, without being specifically assigned to 6.10a or 6.10b. The difference

172 in 31P NMR chemical shifts of 6.12a and 6.12b are somewhat larger than 6.10a and 6.10b, which are 22.1 ppm and 22.8 ppm. However, no decent separation of these diastereomers has been achieved for either case.

Ph Ph Ph Ph P P

Pd Pd H BF H2N 4 Br P P Ph Ph NH AgBF Ph Ph 2 4 H + CHCl Ph Ph 6.12a Ph Ph 3 P P

Pd Pd BF4 NH2 Br P P H Ph Ph Ph Ph

6.86.11 6.12b Scheme 6.2. Reaction of PCP pincer complex with (S)-α –tert-butylethylamine.

Nevertheless, an alternative method has been carried out, which is the introduction of a chiral amine, (S)-α-phenylethtylamine 6.9 to react with the aldehyde precursor 6.13. The resulting diimine ligand 6.14 reacts with Pd2(dba)3 and affords a mixture of complexes 6.15a and

6.15b as two diastereomers (Scheme 3), which can be separated by flash column chromatography.

173 Ph H Ph H O O H2N H N N p-TsOH (cat.) + I C6H6 Δ I 6.13 6.9 6.14

Ph H Ph H N N

Pd2(dba)3 Pd + Pd C H , RT 6 6 I N N I H H Ph Ph 6.15a 6.15b Scheme 6.3. Synthesis of chiral NCN pincer complexes.

X-ray Studies. Crystal structures of complexes 6.15a and 6.15b have been determined.

Single crystals of compounds 6.15a and 6.15b were grown by slow vapor diffusion of hexane into benzene solution. The molecule structures are depicted in Figure 6.1 and 2. Their absolute configurations are thus determined. In the structure of 6.15b, there are three independent molecules in the asymmetric unit of the P2(1) unit cell, only one of them is shown in Figure 6.2. When compared with the structures of 6.15a and 6.15b, a noticeable difference is seen in the orientation of the methylbenzyl groups attached to the nitrogen donor atoms. In compound 6.15a, the two phenyl rings of the methylbenzyl groups are further apart than 6.15b in either side of the plane of the central benzene ring of m-terphenyl backbone. Such orientation is determined by the crowdness of the iodine atom and the bond rotation of N1-C21 and N2-C29.

As shown in Figure 6.1 and 2, the phenyl rings and the methyl groups attached to C21 or C29 are away from the bulky iodine group.

174

Figure 6.1. ORTEP representation of the molecular structure of 6.15a (40% probability ellipsoids). Hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (o):

Pd-N1, 2.029(1); Pd-N2, 2.033(1); Pd-C1, 1.970(1); Pd-I1, 2.7157(1); N1-Pd-N2, 173.04(4);

C1-Pd-I1, 171.61(4).

175

Figure 6.2. ORTEP representation of the molecular structure of 6.15b (40% probability thermal ellipsoids). Only one of the three independent molecules in the asymmetric unit is shown.

Solvent molecules (benzene) and hydrogen atoms are omitted for clarity. Selected bond lengths

(Å) and angles (o): Pd-N1, 2.024(6); Pd-N2, 2.028(7); Pd-C1, 1.963(8); Pd-I1, 2.7059(8);

N1-Pd-N2, 174.7(3); C1-Pd-I1, 175.5(2).

176 NMR Spectroscopy Studies. In the proton NMR spectroscopy studies of NCN diimine palladium pincer complexes reported in Chapter 4, the chemical shifts of the methyne proton

(CH=NR) range from 8.1 to 8.4 ppm. The chemical shift of methyne proton in 6.15b is 8.15 ppm. However, a large up field shift of the methyne proton is observed for 6.15a, which appears at 7.52 ppm (Figure 6.4, top). Such a result could be rationalized from the interaction of the phenyl ring of the methylphenyl group with the methyne proton due to their short distance about 3.1 Å (Figure 6.3, top), while there is no such interaction for 6.15b due to their much longer distance around 4.5 Å (Figure 6.3, bottom).

Figure 6.3. Further view of complex 6.15a (top) and 6.15b (bottom) emphasizing the proximity of methyne proton with the phenyl ring.

177 Another difference between 6.15a and 6.15b in terms of NMR spectroscopy is the allylic interproton coupling19, 4J(H19-C19=N1-C21-H21). In the 1H NMR analysis of 6.15a, the resonance of H21/H29 was found as doublet of quartets, and the methyne proton H19/H20 showed a doublet; both resonances displayed a coupling constant of 2 Hz. Two-dimension

NMR (COSY) studies have also confirmed this four bond coupling. Such coupling pattern, however, was not observed in compound 6.15b.

Figure 6.4. Comparison of 1H NMR spectra of 6.15a (top) and 6.15b (bottom).

178 6.3 Conclusion

Introduction of chiral imine groups are utilized for resolution of chiral pincer complexes 6.15a and 6.15b with high degree of non-fluxionality. This methodology could thus be applied to the construction of chiral pincer complexes bearing m-terphenyl scaffolds with different metal centers, such as nickel, platinum, iridium, or ruthenium, of which the counterpart xylyl based pincer systems have shown broad applications.6,7,10,20,21

179 6.4 Experimental

General Procedures and Materials

Experiments involving manipulation of air- and water sensitive materials were carried out using Schlenk techniques or in a glove box under nitrogen. Certified A.C.S. grade solvents (THF,

CHCl3, CH2Cl2, benzene, hexanes, methanol, and ethanol) and anhydrous benzene from Fisher were used as received. The NMR spectroscopy measurements were recorded on a Varian Inova

400 or 600 MHz spectrometers. Chemical shifts were referenced to residual solvent signals (1H,

13C NMR). Elemental analyses were performed by Quantitative Technologies, Inc. NJ.

2,6-{2-(S)-PhCH(CH3)N=C(H)C6H4}2C6H3I (6.14)

To a benzene (40 mL) solution of 6.13 (1.00 g, 2.43 mmol) and (S)-α-methylbenzylamine

(0.62 g, 5.1 mmol) in a 100 mL round bottom flask, several pieces of crystalline p-toluene sulfonic acid were added. The resultant mixture was heated to reflux under N2 for 16 h.

Water generated by this reaction was collected by Dean-Stark receiver. After being cooled to room temperature, the solvent was removed under vacuum. The resultant material (1.50 g, 99%) was pure according to NMR spectroscopy and elemental analysis, and was used as is without further purification.

(Chemical shifts of two isomers are reported without specifically assigning to syn- or anti-)1H

NMR (CDCl3, 400 MHz): δ 1.33 (d, JHH = 6.4 Hz, -CH3), 1.52 (dd, JHH = 6.4 Hz, 1.0 Hz, -CH3),

4.19 (quartet, JHH = 6.4 Hz, -CH-), 4.37 (sixtet, JHH = 6.4 Hz, -CH-), 7.16-7.42 (m, 14H),

13 7.43-7.50 (m, 5H), 8.11-8.25 (m, 4H). CNMR (CDCl3, 100 MHz): δ 24.8, 25.1, 25.2, 69.7,

70.0, 70.2, 70.5, 106.5 (Ar(C)-I), 126.7, 126.8, 126.9, 127.0, 127.08, 127.13, 127.4, 127.7, 127.8,

128.0, 128.6, 128.7, 129.5, 129.6, 129.8, 129.9, 130.1, 130.16, 130.22, 130.4, 133.8, 133.9, 134.1,

180 134.2, 145.0, 145.4, 145.8, 146.0, 146.1, 157.6, 157.7, 157.9, 158.1. Anal. Calcd for C36H31N2I:

C, 69.89; H, 5.05; N, 4.53. Found: C, 69.76; H, 4.97; N, 4.22.

[2,6-{2-(S)-PhCH(CH3)N=C(H)C6H4}2C6H3PdI] (6.15)

A mixture of 6.14 (0.30 g, 0.49 mmol) and Pd2(dba)3 (0.23 g, 0.25 mmol) was dissolved in 15 mL anhydrous benzene in a 20 mL vial, and stirred under N2 for 16 h. The reaction mixture was filtered and the solvent was removed in vacuo. The resulting material was purified by flash column chromatography using and silica gel and 20% (V:V) of ethyl acetate in hexanes as eluent.

The two diastereomers were thus separated. The first component to elude through the column was assigned as 6.15a, and the second one was assigned as 6.15b. The absolute configurations were determined by x-ray crystallography.

1 6.15a: H NMR (CDCl3, 400 MHz): δ 1.38 (d, JHH = 6.8 Hz, 6H, -CH3), 5.60-5.65 (m, 2H,

-CH-), 7.14-7.17 (m, 6H), 7.21 (s, 3H), 7.27-7.33 (m, 6H), 7.37-7.41 (m, 2H), 7.50-7.56 (m, 4H),

13 7.60 (d, JHH = 2.0 Hz, 2H, -CH=N-). CNMR (CDCl3, 100 MHz): δ 22.8 (-CH3), 70.0 (-CH-),

125.2, 127.1, 128.4, 128.6, 129.1, 129.2, 130.0, 130.7, 131.5, 132.6, 139.3, 141.0, 141.8, 150.7

(Ar(C)-Pd), 165.0 (-CH=N-). Anal. Calcd for C36H31N2IPd: C, 59.64; H, 4.31; N, 3.86.

Found: C, 59.57; H, 4.19; N, 3.66.

1 6.15b: H NMR (CDCl3, 400 MHz): δ 1.50 (d, JHH = 6.8 Hz, 6H, -CH3), 5.69 (q, JHH = 6.8 Hz,

2H, -CH-), 6.60 (d, JHH = 7.6 Hz, 4H), 6.65 (d, JHH = 7.6 Hz, 2H), 6.90 (d, JHH = 7.2 Hz, 2H),

6.99-7.03 (m, 5H), 7.17 (t, JHH = 7.6 Hz, 2H), 7.28-7.32 (m, 2H), 7.34-7.40 (m, 4H), 8.25 (s, 2H,

13 -CH=N-). CNMR (CDCl3, 100 MHz): δ 23.1 (-CH3), 70.3 (-CH-), 124.8, 126.7, 127.2,

128.1, 128.5, 129.9, 130.5, 131.7, 132.1, 140.2, 141.38, 141.43, 150.1 (Ar(C)-Pd), 164.9

(-CH=N-). Anal. Calcd for C36H31N2IPd: C, 59.64; H, 4.31; N, 3.86. Found: C, 59.80; H,

4.21; N, 3.39.

181 NMR Spectra

31 Figure 6.5. P NMR spectrum (CDCl3, 161.8 MHz) for diastereomers 6.10a and 6.10b.

1 Figure 6.6. H NMR spectrum (CDCl3, 400 MHz) for diastereomers 6.10a and 6.10b.

182

31 Figure 6.7. P NMR spectrum (CDCl3, 161.8 MHz) for diastereomers 6.12a and 6.12b.

1 Figure 6.8. H NMR spectrum (CDCl3, 400 MHz) for ligand 6.14.

183

13 Figure 6.9. C NMR spectrum (CDCl3, 100 MHz) for ligand 6.14.

13 Figure 6.10. C NMR spectrum (CDCl3, 100 MHz, aromatic region) for ligand 6.14.

184

1 Figure 6.11. H NMR spectrum (CDCl3, 400 MHz) for complex 6.15a.

1 Figure 6.12. H NMR spectrum (CDCl3, 400 MHz, aromatic) for complex 6.15a.

185

13 Figure 6.13. C NMR spectrum (CDCl3, 100 MHz) for complex 6.15a.

13 Figure 6.14. C NMR spectrum (CDCl3, 100 MHz, aromatic) for complex 6.15a.

186

1 Figure 6.15. H NMR spectrum (CDCl3, 400 MHz) for complex 6.15b.

1 Figure 6.16. H NMR spectrum (CDCl3, 400 MHz, aromatic) for complex 6.15b.

187

13 Figure 6.17. C NMR spectrum (CDCl3, 100 MHz) for complex 6.15b.

13 Figure 6.18. C NMR spectrum (CDCl3, 100 MHz, aromatic) for complex 6.15b.

188 6.5 Works Cited.

(1) Ohff, M.; Ohff, A.; vanderBoom, M. E.; Milstein, D. J. Am. Chem. Soc. 1997, 119, 11687.

(2) Bergbreiter, D. E.; Osburn, P. L.; Liu, Y. S. J. Am. Chem. Soc. 1999, 121, 9531.

(3) Peris, E.; Loch, J. A.; Mata, J.; Crabtree, R. H. Chem. Commun. 2001, 201.

(4) Eberhard, M. R. Org. Lett. 2004, 6, 2125.

(5) Yoon, M. S.; Ryu, D.; Kim, J.; Ahn, K. H. Organometallics 2006, 25, 2409.

(6) Dani, P.; Karlen, T.; Gossage, R. A.; Gladiali, S.; van Koten, C. Angew. Chem. Int. Edit. 2000,

39, 743.

(7) Jensen, C. M. Chem. Commun. 1999, 2443.

(8) Morales-Morales, D.; Redon, R.; Yung, C.; Jensen, C. M. Chem. Commun. 2000, 1619.

(9) Krogh-Jespersen, K.; Czerw, M.; Summa, N.; Renkema, K. B.; Achord, P. D.; Goldman, A. S.

J. Am. Chem. Soc. 2002, 124, 11404.

(10) Gottker-Schnetmann, I.; White, P.; Brookhart, M. J. Am. Chem. Soc. 2004, 126, 1804.

(11) Zhu, K. M.; Achord, P. D.; Zhang, X. W.; Krogh-Jespersen, K.; Goldman, A. S. J. Am. Chem.

Soc. 2004, 126, 13044.

(12) Longmire, J. M.; Zhang, X. M.; Shang, M. Y. Organometallics 1998, 17, 4374.

(13) Williams, B. S.; Dani, P.; Lutz, M.; Spek, A. L.; van Koten, G. Helv. Chim. Acta 2001, 84,

3519.

(14) Takenaka, K.; Minakawa, M.; Uozumi, Y. J. Am. Chem. Soc. 2005, 127, 12273.

(15) Motoyama, Y.; Kawakami, H.; Shimozono, K.; Aoki, K.; Nishiyama, H. Organometallics

2002, 21, 3408.

(16) Lee, H. M.; Zeng, J. Y.; Hu, C. H.; Lee, M. T. Inorg. Chem. 2004, 43, 6822.

(17) Grundemann, S.; Albrecht, M.; Loch, J. A.; Faller, J. W.; Crabtree, R. H. Organometallics

189 2001, 20, 5485.

(18) Diez-Barra, E.; Guerra, J.; Lopez-Solera, I.; Merino, S.; Rodriguez-Lopez, J.;

Sanehez-Verdu, P.; Tejeda, J. Organometallics 2003, 22, 541.

(19) Barfield, M.; Spear, R. J.; Sternhell, S. Chem. Rev. 1976, 78, 593.

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W.; vanKoten, G. Organometallics 1997, 16, 4985.

(21) Gorla, F.; Togni, A.; Venanzi, L. M.; Albinati, A.; Lianza, F. Organometallics 1994, 13,

1607.

190 Chapter 7. Self-Assembly of Cationic Palladium Complexes by Redistribution of Pyridine

Ligands*

7.1. Introduction

The design of supramolecular coordination compounds by self-assembly is a rapidly developing research area.1-3 The combination of coordination chemistry and hydrogen bonding has proven to be a powerful method in constructing self-assembly polymers and in applications for crystal engineering.4-7 Four-coordinate palladium (II) complexes with square-planar geometry and various pyridine-based ligands, in particular, are one very large class of useful building blocks for producing an amazing array of interesting molecular architectures.8-11

In the course of our own work to develop new cationic palladium complexes having pyridine supporting ligands and weakly coordinating anions, we have stumbled upon an unexpected redistribution of pyridine ligands during an attempted synthesis of one such complex. Herein we detail an interesting 1-D polymeric solid-state structure and the solution NMR studies that reveal solvent dependent dynamic ligand exchange processes.

______

* Adapted from the published paper: Ma, L., Smith, R. C.; Protasiewicz, J. D. Inorg. Chim. Acta 2005, 358, 3478.

191 7.2 Experimental

Solvents were dried using activated molecular sieves prior to use. NMR spectra were recorded using Varian Inova 400 spectrometer and were referenced to residual solvent signals.

12 13 The complex [Pd(py)2(OAc)2] (7.1) was synthesized using literature methods to prepare analogous compounds.

7.2.1 [Pd(OAc)(py)3][B(C6F5)4] (7.2)

Complex 7.1 (0.390 g, 1.02 mmol) and [Li((OEt2)2.5)][B(C6F5)4] (0.881 g, 1.01 mmol) were dissolved in 15 mL acetonitrile, followed by the addition of pyridine (0.520 g, 6.57 mmol). A white precipitate was observed after 5 minutes of stirring. After continued stirring overnight the precipitate was filtered, and the solvent was removed in vacuo. The resultant solid was rinsed with n-pentane, and dried in vacuo for 4 hours to yield 1.04 g, (95.1%) of 7.2; m.p.

o 1 192-193 C; H NMR (CDCl3): δ 1.82 (s, 3H), 8.54 (m, 4H), 8.46 (m, 2H), 7.87-7.95 (m, 3H),

7.45 (m, 4H), 7.40 (m, 2H). An analytically pure sample was prepared by recrystallization by diffusion of n-pentane into a THF solution of 7.2. Calc. for C45H26O3F20N3BPd (7.2•THF): C,

46.84%; H, 2.27%; N, 3.64%. Found: C, 46.80%; H, 2.08%; N, 3.62%.

7.2.2 X-ray structure determination of complex 7.2

Diffraction data were collected with a Siemens P4 instrument (Mo Kα radiation λ = 0.710 73

Å)). X-ray quality crystals of 7.2 were grown by diffusion of n-pentane into a saturated THF solution. Crystals were mounted onto glass fibers using epoxy. Crystals were judged to be

192 acceptable on the basis of ω scans and rotation photography. A random search located reflections to generate the reduced primitive cell, and cell lengths were corroborated by axial photography. Additional reflections with 2θ values near 25° were appended to the reflection array and yielded the refined cell constants. Data were collected as presented in Table 7.1 and were corrected for absorption (empirical φ scans). Computations were performed using

SHELXTL version 6.1 (Bruker AXS). Full data have been deposited with the Cambridge

Crystallographic Database Centre (CCDC 267070).

193 Table 7.1. Crystal Data and Structure Refinement for 7.3·2THF.

Empirical formula C45H26BF20N3O3Pd Formula weight 1153.90 Temperature (K) 298 Wavelength (Å) 0.71073 Crystal system Triclinic Space group P-1 Unit cell dimensions a = 10.8949(10) Å b = 14.3485(16) Å c = 16.7006(13) Å α = 109.840(8) ° β = 104.312(7) ° γ = 98.318(9) ° Volume (Å3) 2303.5(4) Z 2 Density (calcd Mg/m3) 1.664 Absorption coeff. (mm-1) 0.528 F(000) 1144 Crystal size (mm) 0.28 x 0.28 x 0.28 Crystal color & shape Yellow block θ range data collection 2.74-48.00 Limiting indices -12 < h < 1 -15 < k < 15 -18 < l < 15 Reflections collected 8310 Independent reflections 7041 (Rint = 0.019) Refinement method Full-matrix least- squares on F2 Data/restraint/parameters 7041/0/733 Goodness-of-fit on F2 1.009 Final R indices [I>2σ(I)] R1 = 0.0329 wR2 = 0.0763 R indices (all data) R1 = 0.0475 wR2 = 0.0838 a b 2 2 2 2 2 2 0.5 -1 2 2 2 R(F) = Σ||Fo| - |Fc||/Σ|Fo|. RW(F ) = [Σ{w(Fo - Fc ) }/Σ{w(Fo ) }] ; w = σ (Fo ) + (aP) + bP,

2 2 where P = [Fo + 2Fc ]/3 and a and b are constants adjusted by the program.

194 7.3. Results and Discussion

7.3.1. Synthetic procedure

Reaction of [Li((OEt2)2.5)][B(C6F5)4] with [Pd(OAc)2(py)2] in the presence of pyridine was undertaken with the intent to prepare [Pd(OAc)(py)3][B(C6F5)4] (7.2, Scheme 7.1). From such a reaction an air-stable white solid with a relatively sharp melting point of 192-193 oC was obtained in high yield. Proton NMR spectra of 7.2 in CDCl3 are consistent with this assignment and showed two resolvable sets of signals for the para and meta pyridine protons in a 2:1 ratio.

Elemental analyses further indicated its composition to be in agreement with the proposed formulation. It was thus somewhat surprising when the results of a single crystal X-ray structure analysis revealed a different structure.

OAc N Pyridine N Pd N + Li(OEt2)2.5B(C6F5)4 N Pd OAc B(C6F5)4 CH3CN OAc N

1 2 Scheme 7.1. Synthesis of complex 7.2.

195 7.3.2. X-ray crystallography

The results of an X-ray diffraction study on a crystal of "7.2"•THF revealed that while the empirical formula, [Pd(OAc)(py)3][B(C6F5)4] is correct, a different connectivity leads to a much more complicated and interesting structure (Figures 7.1-2) involving two different types of palladium units. The crystal structure shows that the material in the solid state is actually formulated as [Pd(py)4][Pd(OAc)2(py)2][B(C6F5)4]2•2THF (7.3•2THF). Each palladium center

2+ resides on a crystallographic inversion center. The two palladium entities [Pd(py)4] (7.4) and [Pd(OAc)2(py)2] (7.1) are bridged by the oxygen atoms of the acetate groups forming a polymeric chain of palladium and acetato groups (Figure 7.2) aligned along the a-axis of the crystal.

Figure 7.1. An ORTEP drawing (30% probability thermal ellipsoids) of 7.3 with atom labeling scheme. Solvent molecule (THF), [B(C6F5)4] anions, and hydrogen atoms have been omitted for clarity.

196

Table 7.2. Selected bond lengths (Å) and angles (º) for complex 7.3•2THF

Pd(1)-N(1) 2.016(3) Pd(1)-N(2) 2.030(3) Pd(2)-N(3) 2.028(3) Pd(2)-O(1) 1.999(3) C(16)-O(1) 1.289(4) C(16)-O(2) 1.220(4) Pd(1)•••O(2A) 3.113

N(1)-Pd(1)-N(2) 89.89(10) N(2)-Pd(1)-N(1A) 90.11(11) N(3)-Pd(2)-O(1) 91.01(11) O(1)-Pd(2)-N(3A) 88.99(11) Pd(2)-O(1A)-C(16A) 118.7(2) O(1A)-C(16A)-O(2A) 123.4(3)

The geometry within both palladium units is square planar. The palladium-nitrogen

2+ distances in both units are within norms established by other structures having the the [Pd(py)4]

14-16 unit. Specific geometries within the [Pd(OAc)2(py)2] unit can be closely compared to those

17 reported for [Pd(OAc)2(py)2]·H2O. The distance between two palladium atoms in 7.3 is 5.447

Å, well beyond that required for any direct interaction between these two palladium atoms. The

2+ distance between the palladium atom of [Pd(py)4] and the oxygen atom of the acetate group in

[Pd(OAc)2(py)2] is 3.113 Å, and is indicative of a weak intermolecular interaction. By comparison, the intramolecular Pd•••O interaction involving the carbonyl oxygen atom of the

197 acetate group in palladium acetate complexes is often shorter. For example, the structure of

17 [Pd(OAc)2(py)2]·H2O reveals a Pd•••O contact of 3.077Å. Thus it is unlikely that the sole force responsible for ligand redistribution and aggregation of the palladium site is the intermolecular Pd•••O interactions. In the solid state, aggregation may be aided by the additive effects of the weak intermolecular Pd•••O interactions and by additional packing forces. It should also be noted that the oxygen atom, as it approaches the palladium center of the

2+ [Pd(py)4] unit, encounters will face a blockade by the four ortho-hydrogen atoms of the four pyridyl groups. These hydrogens are found at nearly the sum of the van der Waals radii of oxygen and hydrogen (compare 2.6Å to observed 2.50-2.62Å). Closer approach is thus probably inhibited by these atoms.

Figure 7.2. Crystal structure of 7.3. Solvent molecules (THF), hydrogen atoms and counter anions have been omitted for clarity.

198

7.3.3 1H NMR spectroscopy

As mentioned previously, 1H NMR spectra of the material we initially assigned as 7.2 in

+ CDCl3 suggested a single species consistent for the [Pd(OAc)(py)3] cation. We thus decided to examine of the spectra of this material in CD3CN solution (Fig. 3). In this particular solvent the presence of three complexes can be identified. Specifically, the spectra revealed four doublets in the region where the pyridine o-H resonances are expected to appear (these signals are the most resolved of the pyridine resonances), and two singlets for the acetate methyl groups.

For a sample of pure 7.2, one would expect two sets of ortho-pyridine resonances in a 1:2 ratio

(designated b and c in Scheme 7.2), while for a sample of pure 7.3 one would expect to observe two sets of ortho-pyridine resonances in a 1:2 ratio (designated as d and a in Scheme 7.2). The presence of 4 such signals most likely indicates that palladium species 7.2, 7.3 and 7.4 are all in solution, as shown in Scheme 7.2. Likewise, there are two, not one, methyl resonances (e and f) for the acetate groups. Comparison of the 1H NMR spectra of 7.1 (Figure 7.3, middle) with that of 7.3 (Figure 7.3, upper) shows that indeed one set of signals (d and e) match those of 7.1

1 exactly. From the integration of the protons in H NMR spectrum, the equilibrium constant Keq in Scheme 7.2 is calculated to be 1.9x10-2. As a means to further corroborate this assignment, the 1H NMR spectrum of a solution of 7.2 and one half equivalent of 7.1 was obtained (Figure

7.3, bottom). As expected from the equilibrium portrayed in Scheme 7.2, the signals for 7.4

-2 rise in intensity, and a comparable Keq is calculated (1.3x10 ). The likely reduced solubility of the dication relative to the monocation, and the dynamic equilibrium between the two forms may be responsible for selective crystallization of the material as 7.3•2THF.

199 2

N N N Keq 2 N Pd OAc AcO Pd OAc + N Pd N b N cdN N a

2 14

Scheme 7.2. Ligand redistribution reaction involving 7.2.

The ligand disproportion seen in this system is reflective of the known general facility for coordination isomerism to occur in palladium complexes, a property that have proven useful for constructing supramolecular structures.18,19 For a palladium acetate systems, reports of the

2+ equilibria between [Pd(OAc)2(PP)], [Pd(PP)2] and [Pd(OAc)2] (PP = dppe or dppp) are perhaps closest to the pyridine complexes detailed herein.20-22

200

1 Figure 7.3. H NMR (400 MHz, CD3CN) spectra of (a) solution of 7.2 showing equilibrium mixture of 7.1, 7.2, and 7.3 (upper spectrum) (B) solution of 7.1 (middle spectrum) (C) solution of 7.2 and 0.5 equiv. 7.1 (lower spectrum). All solutions in CD3CN.

201 7.4 Conclusions

The crystal structure of a new cationic palladium complex revealed the formation of an interesting self-assembled coordination polymer by redistribution of the pyridine ligands. The resulting 1-D polymer is composed of two different palladium complex units assembled by the

2+ interaction of [Pd(py)4] cations and the neutral species [Pd(OAc)2(py)2] by bridging acetate oxygen atoms. Proton NMR studies have demonstrated that there is an equilibrium in solution, which may be driven in one direction by intermolecular interactions in the solid state. It may thus be possible to construct additional new self-assembly polymers via ligand redistribution. This work suggests that future efforts at assembling supramolecular ensembles using palladium complexes might take advantage of the pyridine ligand lability by intentional introduction of two different palladium complexes as ligand sources for redistribution reactions to attain the desired structures.

202 7.5 Works Cited

(1) Lehn, J.-M., Atwood, J. L., Davies, J. E. D., Macnicol, D. D, Vogtle, F., Comprehensive

Supramolecular Chemistry. Pergamon, Oxford, 1996.

(2) Lehn, J.-M., Supramoleular Chemistry: Concepts and Perspectives. VCH, Weinheim, 1995.

(3) Braga, D.; Grepioni, F.; Desiraju, G. R. Chem. Rev. 1998, 98, 1375.

(4) Zaworotko, M. J. Chem. Commun. 2001, 1.

(5) Moulton, B.; Zaworotko, M. J. Curr. Opin. Solid State Mater. Sci. 2002, 6(2), 117.

(6) Carlucci, L.; Ciani, G.; Proserpio, D. M. Coord. Chem. Rev. 2003, 246(1-2), 247.

(7) Brammer, L. Chem. Soc. Rev. 2004, 33(8), 476.

(8) Leininger, S.; Olenyuk, B.; Stang, P. J. Chem. Rev. 2000, 100, 853.

(9) Fujita, M. Chem. Soc. Rev. 1998, 27, 417.

(10) Seidel, S. R.; Stang, P. J. Acc. Chem. Res. 2002, 35, 972.

(11) Stang, P. J.; Olenyuk, B. Acc. Chem. Res. 1997, 30, 502.

(12) Morehouse, S. M.; Powell, A. R.; Heffer, J. P.; Stephenson, T. A.; Wilkinson, G. Chemistry

& Industry (London, United Kingdom) 1964, 544.

(13) Halligudi, S. B.; Bhatt, K. N.; Khan, N. H.; Kurashy, R. I.; Venkatsubramanian, K.

Polyhedron 1996, 15, 2093.

(14) Tebbe, K.-F.; Grafe-Kavoosian, A.; Freckmann, B. Z. Naturforsch., B:Chem. Sci. 1996, 51,

999.

(15) Holzbock, J.; Sawodny, W.; Thewalt, U. Z. Anorg. Allgem. Chem. 2000, 626, 2563.

(16) Lutz, M.; Spek, A. L.; Kleij, A. W.; van Koten, G. CSD Version 5.26, entry VEXCOQ

(2000).

(17) Kravtsova, S. V.; Romm, I. P.; Stash, A. I.; Belsky, V. K. Acta Crystallogr. Sect. C-Cryst.

203 Struct. Commun. 1996, 52, 2201.

(18) Kostic, N. M.; Dutca, L. M., Palladium. In Comprehensive Coordination Chemistry II, 1st ed.; McCleverty, J. A.; Meyer, T. J. (Eds.), Pergamon, Boston, 2004; vol. 6, p. 555.

(19) Yeh, R. M.; Davis, A. V.; Raymond, K. N., Supramolecular systems: self-assembly. In

Comprehensive Coordination Chemistry II, 1st ed.; McCleverty, J. A.; Meyer, T. J. (Eds.),

Pergamon Press, Boston, 2004; vol. 7, p. 327.

(20) Bianchini, C.; Lee, H. M.; Meli, A.; Oberhauser, W.; Peruzzini, M.; Vizza, F.

Organometallics 2002, 21, 16.

(21) Bianchini, C.; Meli, A.; Oberhauser, W. Organometallics 2003, 22, 4281.

(22) Pivovarov, A. P.; Novikova, E. V.; Belov, G. P. Russ. J. Coord. Chem. 2000, 26, 38.

204 Chapter 8. Conclusions

8.1 Thesis Summary

t 1 Pincer ligands, including PCP diphosphine 2,6-(2-CH2PR2C6H4)2C6H3Br (R = Ph, Cy, Bu),

NCN diimine 2,6-{2-R’N=C(H)C6H4}2C6H3I (R’ = Ph, 2,6-Me2C6H3, 2,4,6-Me3C6H2, Cy,

2 3 (S)-α-methylbenzyl) and NCN diamine 2,6-(2-Me2NCH2C6H4)2C6H3I have been synthesized and characterized (Scheme 8.1). A similar approach has been taken to prepare diphosphinite

PCP pincer ligands (8.1-8.3) and complexes.1,4 All of these free ligands show two stable conformations syn- and anti- on NMR time scale.

PR (R=Cy or tBu) HPR NR (X = Br) 2 2 Br (X = I) CH2OH or LiPPh2

PBr3 X X X X CH2OH NR PR2 Br 3.1 3.2 3.3 RNH2 4.7 4.8 4.9 4.10 R = Ph Cy tBu NaBH4 R = Ph Xyl Mes Cy O E

X X E (X = Br, I) PR2 O (E = OMe) (E = Me) O (X = I) NMe2 1. Ti(OiPr)4 BBr Ag(NO3)2 3 + Me2NH·HCl/NEt3 H O+ NBS NaOAc, H3O 3 2. NaBH4 X R PCl O 2 X CHBr Et N OH 2 PR 3 2 NMe 8.1 8.2 8.3 2 X R = Ph iPr tBu X 5.10 OH CHBr2

Scheme 8.1. Synthetic schemes for PCP and NCN pincer ligands.

Upon reacting with Pd2(dba)3, both the syn- and anti- isomers of the ligands are converted to the desired pincer complexes by oxidative addition of palladium into the aryl C-Br bond

(Scheme 8.2).

205

NR NMe PR2 2

X X X

NR NMe PR2 2

Pd2(dba)3 or Ni(COD)2

Me Me R R R N P N

M M M I Br I N P N Me Me R R R

3.1: M = Pd, R = Ph 4.11: M = Pd, R = Ph 5.10: M = Pd 3.2: M = Pd, R = Cy 4.12: M = Pd, R = Xyl 5.12: M = Ni 3.3: M = Pd, R = tBu 4.13: M = Pd, R = Mes 3.4: M = Ni, R = Ph 4.14: M = Pd, R = Cy

Scheme 8.2. Synthetic schemes for PCP and NCN pincer complexes.

These pincer complexes have been characterized by NMR spectroscopy and single crystal

X-ray crystallography. Structure analyses of these pincer complexes reveal a C2 symmetric environment. These new systems have the largest twist angles determined to date for pincer complexes. Variable temperature NMR experiments for complexe 3.3 revealed that the tert-butyl groups most proximal to the bromine atom face steric clashes with the bromine atom and cause hindered rotations about the P-CMe3 bond. Similar hindered rotations about the aryl

C-N bonds were observed for complexes 4.12 and 4.13. These variable temperature NMR experiments also indicated that these pincer complexes display a very high degree of non-fluxionality (up to 130 °C), which prevents the interconversion of possible atropisomers.

206 Introduction of chiral imine groups were utilized for resolution of chiral pincer complexes, and the successful separation and characterization of 6.15a and 6.15b (Scheme 8.3) have further demonstrated the rigidity and chiral nature of these pincer systems.

Ph H Ph Ph H Ph H H N N N N Pd2(dba)3 Pd + Pd C6H6, RT I N N I I H H Ph Ph 6.14 6.15a 6.15b Scheme 8.3. Synthesis of chiral NCN pincer complexes.

In terms of applications, these palladium pincer complexes have been tested as catalysts for

Suzuki-Miyaura coupling reactions. Some preliminary results indicated that these complexes are active catalysts in the coupling of phenyl boronic acid with aryl bromides or aryl iodides.

Further studies of these catalytic reactions would offer better understanding of the properties of these new pincer systems.

8.2 Perspectives

One of the most important features of these pincer systems containing m-terphenyl scaffolds is their rigidity and chirality, and the enantiomerically pure pincer complexes have great potential in the application of catalytic asymmetric synthesis. The future research in this topic could be focused on not only the chiral palladium pincer complexes, but also the expansion of this pincer family to other metal centers, such as nickel, platinum, iridium and ruthenium, of which the counterpart m-xylyl based pincer complexes have shown broad applications.5-9 For example, nickel pincer complex 2,6-(CH2NMe2)2C6H3NiBr has been proved to be a very effective catalyst

5 for the Kharasch addition of methylacrylate with CCl4. Ruthenium pincer complex

207 2,6-(CH2PPh2)2C6H3Ru(PPh3)OSO2CF3 has shown high catalytic activity in transfer hydrogenation.9 If the corresponding m-terphenyl pincer complexes could be prepared as enantiomerically pure materials, stereoselectivity of these catalytic reactions could be afforded.

The m-terphenyl platform could be expanded to different ligand systems, such as PNP pincer system. A PNP palladium pincer complex [2,6-(CH2PPh2)2PyPd(NCC6F5)](BF4)2 (Py = pyridine) has been reported, which catalyzes the polycyclization reactions of 1,5- and

10 1,6-dienes. Another similar PNP palladium pincer complex [2,6-(CH2PPh2)2PyPdCl]Cl catalyzes intramolecular hydroamination of unactivated alkenes.11 However, only racemic mixture products have been obtained for these reactions. Therefore, the next approach will be the modification of the central benzene ring of the m-terphenyl into pyridine to construct a new type of chiral PNP pincer complexes.

208 8.3 Works Cited

(1) Ma, L.; Woloszynek, R. A.; Chen, W.; Ren, T.; Protasiewicz, J. D. Organometallics 2006, 25,

3301.

(2) Ma, L.; Imbesi, P. M.; Updegraff III, J. B.; Hunter, A. D.; Protasiewicz, J. D. Inorg. Chem.

2006, submitted.

(3) Ma, L.; Wobser, S. D.; Protasiewicz, J. D. manuscript in preparation.

(4) Woloszynek, R. A.; Ma, L.; Protasiewicz, J. D. unpublished results.

(5) vandeKuil, L. A.; Grove, D. M.; Gossage, R. A.; Zwikker, J. W.; Jenneskens, L. W.; Drenth,

W.; vanKoten, G. Organometallics 1997, 16, 4985.

(6) Jensen, C. M. Chem. Commun. 1999, 2443.

(7) Gottker-Schnetmann, I.; White, P.; Brookhart, M. J. Am. Chem. Soc. 2004, 126, 1804.

(8) Gorla, F.; Togni, A.; Venanzi, L. M.; Albinati, A.; Lianza, F. Organometallics 1994, 13, 1607.

(9) Dani, P.; Karlen, T.; Gossage, R. A.; Gladiali, S.; van Koten, C. Angew. Chem. Int. Edit. 2000,

39, 743.

(10) Koh, J. H.; Gagne, M. R. Angew. Chem.-Int. Edit. 2004, 43, 3459.

(11) Michael, F. E.; Cochran, B. M. J. Am. Chem. Soc. 2006, 128, 4246.

209 Appendix 1. Crystal Structure Determinations and Tables of Bond Lengths and Angles

A1. X-ray Crystallographic Experiments

3.1: The X-ray intensity data were measured at 300 K on a Bruker SMART 1000 CCD-based

X-ray diffractometer system equipped with a Mo-target X-ray tube (λ = 0.71073 Å) operated at

2000 watts power (Operated at University of Miami). The detector was placed at a distance of

5.020 cm from the crystal. Data were measured using omega scans of 0.3º per frame for 5 seconds such that a hemisphere was collected. A total of 1271 frames were collected with a final resolution of 0.75 Å. No decay was indicated by the recollection of the first 50 frames at the end of data collection. The frames were integrated with the Bruker SAINT© software package using a narrow-frame integration algorithm, which also corrects for the Lorentz and polarization effects. Absorption corrections were applied using SADABS supplied by George

Sheldrick. The structure was solved and refined using the Bruker SHELXTL© (Version 5.1)

Software. The positions of all non-hydrogen atoms were derived from the Patterson solution. The asymmetric unit consists of a half of the molecule and is related to the other half via a crystallographic 2-fold axis that is coincidental with the C1-Pd-Br vector. With all non-hydrogen atoms being anisotropic and all hydrogen atoms being isotropic the structure was refined to convergence by least squares method on F2, SHELXL-93, incorporated in

SHELXTL.PC V 5.03.

4.11•CHCl3: The X-ray intensity data were measured at 100 K on a Bruker SMART Apex

CCD-based X-ray diffractometer system equipped with a Mo-target X-ray tube (λ = 0.71073 Å) operated at 2000 watts power (operated at Youngstown State University). The crystal was mounted on a glass fiber (pulled from a capillary tube) using mineral oil which was then frozen.

210 The detector was placed at a distance of 5.020 cm from the crystal. Data were measured using omega scans of 0.3º per frame for 10 seconds such that a hemisphere was collected. A total of

7604 independent reflections were collected. The frames were integrated with the Bruker

SAINT© software package using a narrow-frame integration algorithm, which also corrects for the Lorentz and polarization effects. Absorption corrections were applied using SADABS.

The structure was solved and refined using the Bruker SHELXTL© (Version 5.1) software. The positions of all non-hydrogen atoms were derived from the Direct Methods (TREF) solution.

With all non-hydrogen atoms being anisotropic the structure was refined to convergence by least squares method on F2, SHELXL-93, incorporated in SHELXTL.PC V 5.03.

2.13, 2.15, 3.2, 3.3, 4.12-4.14, 5.9-5.12, 6.15a and 6.15b: The X-ray intensity data were measured at 100 K on a Bruker SMART Apex II CCD-based X-ray diffractometer system equipped with a Mo-target X-ray tube (λ = 0.71073 Å) operated at 1500 watts power (operated at

Case Western Reserve University). The crystals were mounted on a MiTeGen micromount using paratone-N which was then frozen (except 5.10, which was mounted on glass fiber with expoxy).

The detector was placed at a distance of 6.00 cm from the crystal. Data were measured using omega scans of 0.5º per frame for 10 seconds. The frames were integrated with the Bruker

SAINT© build in APEX II software package using a narrow-frame integration algorithm, which also corrects for the Lorentz and polarization effects. Absorption corrections were applied using AXScale. The structure was solved and refined using the Bruker SHELXTL© (Version

6.14) software. The positions of all non-hydrogen atoms were derived from the Direct Methods

(TREF) solution. With all non-hydrogen atoms being anisotropic and all hydrogen atoms being isotropic the structure was refined to convergence by least squares method on F2, XSHELL

(Version 6.3.1), incorporated in SHELXTL (Version 6.14).

211 A2. Crystallographic Data for Compound 2.13.

PPh PPh 2 2 Figure A1. An ORTEP drawing (40% probability thermal ellipsoids) of 2.13 with atom labeling scheme.

Table A1. Crystal Data and Structure Refinement for 2.13.

Complex 2.13

Empirical formula C44H35Br2P2

Formula weight 705.57

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Triclinic

Space group P-1

212 Unit cell dimensions a = 9.3449(2) Å α = 78.905(1)°

b = 12.4753(2) Å β = 81.846(1)°

c = 15.4024(3) Å γ = 82.708(1)°

Vo l u me ( Å 3) 1735.05(6)

Z 2

Density (calcd. g/cm3) 1.351

Absorption coeff. (mm-1) 1.308

F(000) 728

Crystal size (mm) 0.45×0.36×0.35

Crystal color & shape Colorless block

θ range data collection 1.36-27.50

Limiting indices -12< h <12 -16< k < 16 -20< l < 20

Reflections collected 32730

Independent reflections 7923 (Rint = 0.0239)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 7923/0/424

Goodness-of-fit on F2 1.063

Final R indices [I>2σ(I)]a,b R1 = 0.0284 wR2 = 0.0757

R indices (all data) R1 = 0.0347 wR2 = 0.0792

a b 2 2 2 2 2 2 0.5 -1 2 2 2 R(F) =Σ||Fo| - |Fc||/Σ|Fo|. RW(F ) = [Σ{w(Fo - Fc ) }/Σ{w(Fo ) }] ; w = σ (Fo ) + (aP) + bP, where

2 2 P= [Fo + 2Fc ]/3 and a and b are constants adjusted by the program.

213 Table A2. Bond lengths (Å) and angles (°) for 2.13.

P(1)-C(27) 1.8386(16) C(13)-C(14) 1.406(2)

P(1)-C(21) 1.8435(16) C(14)-C(15) 1.401(2)

P(1)-C(19) 1.8549(16) C(14)-C(20) 1.505(2)

P(2)-C(39) 1.8285(19) C(15)-C(16) 1.384(3)

P(2)-C(33) 1.8380(18) C(16)-C(17) 1.385(3)

P(2)-C(20) 1.8681(16) C(17)-C(18) 1.384(2)

Br(1)-C(1) 1.9023(15) C(21)-C(22) 1.393(2)

C(1)-C(2) 1.401(2) C(21)-C(26) 1.395(2)

C(1)-C(6) 1.403(2) C(22)-C(23) 1.392(2)

C(2)-C(3) 1.395(2) C(23)-C(24) 1.381(3)

C(2)-C(13) 1.496(2) C(24)-C(25) 1.389(3)

C(3)-C(4) 1.385(2) C(25)-C(26) 1.387(2)

C(4)-C(5) 1.384(2) C(27)-C(32) 1.393(2)

C(5)-C(6) 1.398(2) C(27)-C(28) 1.393(2)

C(6)-C(7) 1.493(2) C(28)-C(29) 1.386(3)

C(7)-C(12) 1.400(2) C(29)-C(30) 1.383(3)

C(7)-C(8) 1.401(2) C(30)-C(31) 1.384(3)

C(8)-C(9) 1.395(2) C(31)-C(32) 1.389(2)

C(8)-C(19) 1.511(2) C(33)-C(34) 1.390(3)

C(9)-C(10) 1.391(2) C(33)-C(38) 1.394(3)

C(10)-C(11) 1.377(3) C(34)-C(35) 1.392(3)

C(11)-C(12) 1.386(2) C(35)-C(36) 1.381(3)

C(13)-C(18) 1.395(2) C(36)-C(37) 1.373(4)

214 C(37)-C(38) 1.393(3) C(5)-C(6)-C(7) 118.65(14)

C(39)-C(44) 1.391(3) C(1)-C(6)-C(7) 124.05(14)

C(39)-C(40) 1.407(2) C(12)-C(7)-C(8) 119.18(14)

C(40)-C(41) 1.383(3) C(12)-C(7)-C(6) 117.42(14)

C(41)-C(42) 1.384(3) C(8)-C(7)-C(6) 123.39(13)

C(42)-C(43) 1.385(3) C(9)-C(8)-C(7) 118.88(14)

C(43)-C(44) 1.388(3) C(9)-C(8)-C(19) 118.62(14)

C(7)-C(8)-C(19) 122.49(13)

C(27)-P(1)-C(21) 99.92(7) C(10)-C(9)-C(8) 121.24(16)

C(27)-P(1)-C(19) 99.96(7) C(11)-C(10)-C(9) 119.78(15)

C(21)-P(1)-C(19) 98.96(7) C(10)-C(11)-C(12) 119.79(15)

C(39)-P(2)-C(33) 101.37(8) C(11)-C(12)-C(7) 121.08(16)

C(39)-P(2)-C(20) 102.37(8) C(18)-C(13)-C(14) 119.23(14)

C(33)-P(2)-C(20) 100.25(7) C(18)-C(13)-C(2) 119.18(14)

C(2)-C(1)-C(6) 122.61(14) C(14)-C(13)-C(2) 121.58(14)

C(2)-C(1)-Br(1) 118.33(11) C(15)-C(14)-C(13) 118.10(16)

C(6)-C(1)-Br(1) 119.02(11) C(15)-C(14)-C(20) 118.70(15)

C(3)-C(2)-C(1) 117.53(14) C(13)-C(14)-C(20) 123.18(14)

C(3)-C(2)-C(13) 119.44(14) C(16)-C(15)-C(14) 121.93(16)

C(1)-C(2)-C(13) 123.03(13) C(15)-C(16)-C(17) 119.72(16)

C(4)-C(3)-C(2) 121.22(15) C(18)-C(17)-C(16) 119.22(17)

C(5)-C(4)-C(3) 119.94(15) C(17)-C(18)-C(13) 121.79(16)

C(4)-C(5)-C(6) 121.38(15) C(8)-C(19)-P(1) 113.03(10)

C(5)-C(6)-C(1) 117.24(14) C(14)-C(20)-P(2) 111.55(11)

215 C(22)-C(21)-C(26) 118.42(15) C(34)-C(33)-P(2) 124.23(13)

C(22)-C(21)-P(1) 118.49(12) C(38)-C(33)-P(2) 117.07(15)

C(26)-C(21)-P(1) 123.09(12) C(33)-C(34)-C(35) 121.02(18)

C(23)-C(22)-C(21) 120.59(16) C(36)-C(35)-C(34) 119.5(2)

C(24)-C(23)-C(22) 120.44(16) C(37)-C(36)-C(35) 120.35(19)

C(23)-C(24)-C(25) 119.54(16) C(36)-C(37)-C(38) 120.4(2)

C(26)-C(25)-C(24) 120.12(17) C(37)-C(38)-C(33) 120.1(2)

C(25)-C(26)-C(21) 120.89(16) C(44)-C(39)-C(40) 117.81(17)

C(32)-C(27)-C(28) 118.13(16) C(44)-C(39)-P(2) 123.93(14)

C(32)-C(27)-P(1) 124.99(13) C(40)-C(39)-P(2) 118.12(14)

C(28)-C(27)-P(1) 116.85(13) C(41)-C(40)-C(39) 121.01(18)

C(29)-C(28)-C(27) 121.17(18) C(40)-C(41)-C(42) 120.45(18)

C(30)-C(29)-C(28) 119.89(18) C(41)-C(42)-C(43) 119.11(19)

C(29)-C(30)-C(31) 119.79(17) C(42)-C(43)-C(44) 120.77(19)

C(30)-C(31)-C(32) 120.15(19) C(43)-C(44)-C(39) 120.82(17)

C(31)-C(32)-C(27) 120.79(18)

C(34)-C(33)-C(38) 118.67(17)

216 A3. Crystallographic Data for Compound 2.15.

t P Bu2

t P Bu2 Figure A2. An ORTEP drawing (40% probability thermal ellipsoids) of 2.15 with atom labeling scheme.

Table A3. Crystal Data and Structure Refinement for 2.15.

Complex 2.15·1/2Et2O

Empirical formula C40H56BrOP2

Formula weight 694.70

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Triclinic

217 Space group P-1

Unit cell dimensions a = 9.9794(3) Å α = 83.184(2)°

b = 13.6817(4) Å β = 89.393(2)°

c = 14.0201(4) Å γ = 77.012(2)°

Vo l u me ( Å 3) 1851.83(9)

Z 2

Density (calcd. g/cm3) 1.246

Absorption coeff. (mm-1) 1.226

F(000) 738

Crystal size (mm) 0.24×0.15×0.08

Crystal color & shape Colorless block

θ range data collection 1.46-27.50

Limiting indices -12< h <12 -17< k < 17 -18< l < 18

Reflections collected 35158

Independent reflections 8486 (Rint = 0.552)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 8486/0/376

Goodness-of-fit on F2 1.083

Final R indices [I>2σ(I)] R1 = 0.0509 wR2 = 0.1393

R indices (all data) R1 = 0.0631 wR2 = 0.1450

218 Table A4. Bond lengths (Å) and angles (°) for 2.15.

Br(1)-C(1) 1.908(3) C(13)-C(14) 1.406(4)

P(1)-C(19) 1.861(3) C(14)-C(15) 1.395(4)

P(1)-C(21) 1.891(3) C(14)-C(20) 1.514(4)

P(1)-C(25) 1.896(3) C(15)-C(16) 1.396(4)

P(2)-C(20) 1.863(3) C(16)-C(17) 1.373(4)

P(2)-C(29) 1.884(3) C(17)-C(18) 1.391(5)

P(2)-C(33) 1.889(3) C(21)-C(24) 1.526(4)

C(1)-C(2) 1.394(4) C(21)-C(22) 1.531(4)

C(1)-C(6) 1.397(4) C(21)-C(23) 1.540(4)

C(2)-C(3) 1.400(4) C(25)-C(27) 1.527(5)

C(2)-C(13) 1.497(4) C(25)-C(28) 1.534(4)

C(3)-C(4) 1.380(4) C(25)-C(26) 1.539(5)

C(4)-C(5) 1.386(4) C(29)-C(32) 1.529(5)

C(5)-C(6) 1.397(4) C(29)-C(30) 1.538(4)

C(6)-C(7) 1.493(4) C(29)-C(31) 1.542(4)

C(7)-C(12) 1.399(4) C(33)-C(36) 1.534(4)

C(7)-C(8) 1.406(4) C(33)-C(35) 1.536(5)

C(8)-C(9) 1.391(4) C(33)-C(34) 1.536(4)

C(8)-C(19) 1.516(4) C(37)-C(39) 1.274(9)

C(9)-C(10) 1.389(4)

C(10)-C(11) 1.383(5) C(19)-P(1)-C(21) 98.63(13)

C(11)-C(12) 1.381(4) C(19)-P(1)-C(25) 102.78(14)

C(13)-C(18) 1.396(4) C(21)-P(1)-C(25) 109.51(14)

219 C(20)-P(2)-C(29) 102.49(14) C(11)-C(12)-C(7) 121.1(3)

C(20)-P(2)-C(33) 99.44(14) C(18)-C(13)-C(14) 119.8(3)

C(29)-P(2)-C(33) 110.52(14) C(18)-C(13)-C(2) 118.6(3)

C(2)-C(1)-C(6) 123.0(3) C(14)-C(13)-C(2) 121.5(3)

C(2)-C(1)-Br(1) 118.1(2) C(15)-C(14)-C(13) 118.3(3)

C(6)-C(1)-Br(1) 118.9(2) C(15)-C(14)-C(20) 121.8(3)

C(1)-C(2)-C(3) 117.6(3) C(13)-C(14)-C(20) 119.9(3)

C(1)-C(2)-C(13) 122.2(2) C(14)-C(15)-C(16) 121.1(3)

C(3)-C(2)-C(13) 120.2(3) C(17)-C(16)-C(15) 120.4(3)

C(4)-C(3)-C(2) 120.8(3) C(16)-C(17)-C(18) 119.5(3)

C(3)-C(4)-C(5) 120.2(3) C(17)-C(18)-C(13) 120.9(3)

C(4)-C(5)-C(6) 121.2(3) C(8)-C(19)-P(1) 116.4(2)

C(5)-C(6)-C(1) 117.1(3) C(14)-C(20)-P(2) 117.0(2)

C(5)-C(6)-C(7) 119.7(3) C(24)-C(21)-C(22) 109.3(3)

C(1)-C(6)-C(7) 123.1(3) C(24)-C(21)-C(23) 107.4(2)

C(12)-C(7)-C(8) 119.4(3) C(22)-C(21)-C(23) 108.5(3)

C(12)-C(7)-C(6) 119.4(3) C(24)-C(21)-P(1) 109.6(2)

C(8)-C(7)-C(6) 121.2(2) C(22)-C(21)-P(1) 116.6(2)

C(9)-C(8)-C(7) 118.7(3) C(23)-C(21)-P(1) 105.0(2)

C(9)-C(8)-C(19) 120.6(3) C(27)-C(25)-C(28) 108.8(3)

C(7)-C(8)-C(19) 120.6(3) C(27)-C(25)-C(26) 110.6(3)

C(10)-C(9)-C(8) 121.1(3) C(28)-C(25)-C(26) 107.1(3)

C(11)-C(10)-C(9) 120.2(3) C(27)-C(25)-P(1) 117.4(2)

C(12)-C(11)-C(10) 119.5(3) C(28)-C(25)-P(1) 105.5(2)

220 C(26)-C(25)-P(1) 107.0(2) C(36)-C(33)-C(35) 109.4(3)

C(32)-C(29)-C(30) 109.0(3) C(36)-C(33)-C(34) 107.3(3)

C(32)-C(29)-C(31) 109.5(3) C(35)-C(33)-C(34) 108.9(3)

C(30)-C(29)-C(31) 107.1(3) C(36)-C(33)-P(2) 109.7(2)

C(32)-C(29)-P(2) 116.5(2) C(35)-C(33)-P(2) 117.0(2)

C(30)-C(29)-P(2) 106.1(2) C(34)-C(33)-P(2) 104.0(2)

C(31)-C(29)-P(2) 108.1(2)

221 A4. Crystallographic Data for Compound 3.1.

Ph Ph

P Br Ph Ph

Figure A3. An ORTEP drawing (20% probability thermal ellipsoids) of 3.1 with atom labeling scheme.

Table A5. Crystal Data and Structure Refinement for 3.1.

Complex 3.1

Empirical formula C44H35BrP2Pd

Formula weight 811.97

Temperature (K) 300

222 Wavelength (Å) 0.71073

Crystal system Monoclinic

Space group C2/c

Unit cell dimensions a = 16.1720(7) α = 90.00

b = 14.2258(7) β = 104.392(1)

c = 16.1442(8) γ = 90.00

Vo l u me ( Å 3) 3597.6(3)

Z 4

Density (calcd. g/cm3) 1.499

Absorption coeff. (mm-1) 1.746

F(000) 1640

Crystal size (mm) 0.45×0.30×0.29

Crystal color & shape colorless block

θ range data collection 1.93-25.00

Limiting indices -19< h <15 -16< k < 16 -13< l < 19

Reflections collected 9361

Independent reflections 3160 (Rint = 0.0266)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 3160/0/219

Goodness-of-fit on F2 1.032

Final R indices [I>2σ(I)]a,b R1 = 0.0301 wR2 = 0.0830

R indices (all data) R1 = 0.0379 wR2 = 0.0859

223 Table A6. Bond lengths (Å) and angles (°) for 3.1.

P(1)-C(12) 1.817(3) C(14)-C(15) 1.366(6)

P(1)-C(18) 1.818(3) C(15)-C(16) 1.354(6)

P(1)-C(11) 1.837(3) C(16)-C(17) 1.380(5)

P(1)-Pd 2.3071(7) C(18)-C(19) 1.383(4)

Br-Pd 2.5024(5) C(18)-C(23) 1.392(4)

Pd-C(1) 2.067(4) C(19)-C(20) 1.382(5)

Pd-P(1)#1 2.3071(7) C(20)-C(21) 1.377(5)

C(1)-C(2) 1.389(4) C(21)-C(22) 1.354(5)

C(1)-C(2)#1 1.389(4) C(22)-C(23) 1.379(4)

C(2)-C(3) 1.393(4)

C(2)-C(5) 1.496(4) C(12)-P(1)-C(18) 104.73(14)

C(3)-C(4) 1.375(4) C(12)-P(1)-C(11) 106.39(14)

C(4)-C(3)#1 1.375(4) C(18)-P(1)-C(11) 99.36(14)

C(5)-C(6) 1.388(4) C(12)-P(1)-Pd 112.35(10)

C(5)-C(10) 1.396(4) C(18)-P(1)-Pd 121.41(10)

C(6)-C(7) 1.386(5) C(11)-P(1)-Pd 111.02(10)

C(7)-C(8) 1.368(5) C(1)-Pd-P(1) 84.74(2)

C(8)-C(9) 1.384(5) C(1)-Pd-P(1)#1 84.74(2)

C(9)-C(10) 1.385(4) P(1)-Pd-P(1)#1 169.48(4)

C(10)-C(11) 1.505(4) C(1)-Pd-Br 180.000(1)

C(12)-C(13) 1.380(5) P(1)-Pd-Br 95.26(2)

C(12)-C(17) 1.381(4) P(1)#1-Pd-Br 95.26(2)

C(13)-C(14) 1.387(6) C(2)-C(1)-C(2)#1 120.1(4)

224 C(2)-C(1)-Pd 119.96(19) C(13)-C(12)-C(17) 118.6(3)

C(2)#1-C(1)-Pd 119.96(19) C(13)-C(12)-P(1) 118.2(3)

C(1)-C(2)-C(3) 119.4(3) C(17)-C(12)-P(1) 123.2(3)

C(1)-C(2)-C(5) 121.8(3) C(12)-C(13)-C(14) 119.9(4)

C(3)-C(2)-C(5) 118.6(3) C(15)-C(14)-C(13) 120.4(4)

C(4)-C(3)-C(2) 120.6(4) C(16)-C(15)-C(14) 120.3(4)

C(3)#1-C(4)-C(3) 119.9(5) C(15)-C(16)-C(17) 119.9(4)

C(6)-C(5)-C(10) 119.0(3) C(16)-C(17)-C(12) 120.9(4)

C(6)-C(5)-C(2) 122.2(3) C(19)-C(18)-C(23) 118.4(3)

C(10)-C(5)-C(2) 118.7(3) C(19)-C(18)-P(1) 122.7(2)

C(7)-C(6)-C(5) 120.3(3) C(23)-C(18)-P(1) 118.4(2)

C(8)-C(7)-C(6) 120.6(3) C(20)-C(19)-C(18) 120.6(3)

C(7)-C(8)-C(9) 119.6(4) C(21)-C(20)-C(19) 119.9(3)

C(8)-C(9)-C(10) 120.6(3) C(22)-C(21)-C(20) 120.2(3)

C(9)-C(10)-C(5) 119.8(3) C(21)-C(22)-C(23) 120.6(3)

C(9)-C(10)-C(11) 121.3(3) C(22)-C(23)-C(18) 120.3(3)

C(5)-C(10)-C(11) 118.8(3)

C(10)-C(11)-P(1) 110.1(2)

225 A5. Crystallographic Data for Compound 3.2.

Cy Cy

P Br

Cy Cy Figure A4. An ORTEP drawing (40% probability thermal ellipsoids) of 3.2 with atom labeling scheme.

Table A7. Crystal Data and Structure Refinement for 3.2.

Complex 3.2·CHCl3

Empirical formula C45H60BrCl3P2Pd

Formula weight 955.53

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Triclinic

Space group P-1

226 Unit cell dimensions a = 10.8426(2) α = 99.137(1)

b = 13.5400(3) β = 96.841(1)

c = 15.0123(3) γ = 99.571(1)

Vo l u me ( Å 3) 2121.58(7)

Z 2

Density (calcd. g/cm3) 1.496

Absorption coeff. (mm-1) 1.675

F(000) 984

Crystal size (mm) 0.25×0.10×0.10

Crystal color & shape colorless block

θ range data collection 1.39-27.50

Limiting indices -14< h <14 -17< k < 17 -19< l < 19

Reflections collected 42623

Independent reflections 9731 (Rint = 0.0250)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 9731/0/469

Goodness-of-fit on F2 1.026

Final R indices [I>2σ(I)]a,b R1 = 0.0228 wR2 = 0.0564

R indices (all data) R1 = 0.0264 wR2 = 0.0583

227 A6. Crystallographic Data for Compound 3.3.

tBu tBu

P Br t t Bu Bu Figure A5. An ORTEP drawing (40% probability thermal ellipsoids) of 3.3 with atom labeling scheme.

Table A9. Crystal Data and Structure Refinement for 3.3.

Complex 3.3

Empirical formula C36H51BrP2Pd

Formula weight 732.02

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Triclinic

Space group P-1

228 Unit cell dimensions a = 10.6027(4) α = 102.740(3)

b = 10.8653(4) β = 96.126(3)

c = 10.3273(9) γ = 110.805(2)

Vo l u me ( Å 3) 1679.3(1)

Z 2

Density (calcd. g/cm3) 1.448

Absorption coeff. (mm-1) 1.861

F(000) 756

Crystal size (mm) 0.31×0.13×0.04

Crystal color & shape colorless thin plate

θ range data collection 1.31-27.50

Limiting indices -13< h <13 -14< k < 14 -21< l < 21

Reflections collected 33961

Independent reflections 7646 (Rint = 0.0835)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 7646/0/373

Goodness-of-fit on F2 1.133

Final R indices [I>2σ(I)]a,b R1 = 0.0501 wR2 = 0.1533

R indices (all data) R1 = 0.0660 wR2 = 0.1627

229 Table A10. Bond lengths (Å) and angles (°) for 3.3.

C(1)-C(6) 1.406(7) C(19)-P(1) 1.850(4)

C(1)-C(2) 1.419(6) C(20)-P(2) 1.847(5)

C(1)-Pd(1) 2.061(5) C(21)-C(24) 1.521(7)

C(2)-C(3) 1.388(7) C(21)-C(23) 1.539(7)

C(2)-C(13) 1.507(7) C(21)-C(22) 1.540(8)

C(3)-C(4) 1.393(8) C(21)-P(2) 1.889(5)

C(4)-C(5) 1.376(7) C(25)-C(28) 1.529(6)

C(5)-C(6) 1.403(7) C(25)-C(26) 1.531(7)

C(6)-C(7) 1.503(7) C(25)-C(27) 1.536(6)

C(7)-C(12) 1.399(7) C(25)-P(2) 1.920(5)

C(7)-C(8) 1.404(6) C(29)-C(31) 1.528(7)

C(8)-C(9) 1.397(7) C(29)-C(30) 1.533(6)

C(8)-C(20) 1.514(7) C(29)-C(32) 1.534(7)

C(9)-C(10) 1.384(8) C(29)-P(1) 1.897(5)

C(10)-C(11) 1.381(8) C(33)-C(34) 1.535(7)

C(11)-C(12) 1.386(7) C(33)-C(35) 1.540(7)

C(13)-C(14) 1.395(7) C(33)-C(36) 1.542(8)

C(13)-C(18) 1.403(7) C(33)-P(1) 1.920(5)

C(14)-C(15) 1.393(7) Br(1)-Pd(1) 2.5072(6)

C(14)-C(19) 1.506(7) P(1)-Pd(1) 2.3874(11)

C(15)-C(16) 1.383(7) P(2)-Pd(1) 2.3983(11)

C(16)-C(17) 1.393(8)

C(17)-C(18) 1.385(8) C(6)-C(1)-C(2) 115.7(4)

230 C(6)-C(1)-Pd(1) 120.5(3) C(15)-C(14)-C(13) 118.9(4)

C(2)-C(1)-Pd(1) 123.8(4) C(15)-C(14)-C(19) 122.6(4)

C(3)-C(2)-C(1) 121.6(5) C(13)-C(14)-C(19) 118.3(4)

C(3)-C(2)-C(13) 113.4(4) C(16)-C(15)-C(14) 121.8(5)

C(1)-C(2)-C(13) 124.8(4) C(15)-C(16)-C(17) 119.1(5)

C(2)-C(3)-C(4) 121.4(5) C(18)-C(17)-C(16) 120.0(5)

C(5)-C(4)-C(3) 118.2(5) C(17)-C(18)-C(13) 120.6(5)

C(4)-C(5)-C(6) 121.0(5) C(14)-C(19)-P(1) 113.7(3)

C(5)-C(6)-C(1) 121.8(4) C(8)-C(20)-P(2) 112.4(3)

C(5)-C(6)-C(7) 112.6(4) C(24)-C(21)-C(23) 107.0(4)

C(1)-C(6)-C(7) 125.6(4) C(24)-C(21)-C(22) 110.7(4)

C(12)-C(7)-C(8) 119.0(4) C(23)-C(21)-C(22) 107.6(4)

C(12)-C(7)-C(6) 119.8(4) C(24)-C(21)-P(2) 115.2(4)

C(8)-C(7)-C(6) 120.1(4) C(23)-C(21)-P(2) 107.5(3)

C(9)-C(8)-C(7) 118.9(5) C(22)-C(21)-P(2) 108.5(3)

C(9)-C(8)-C(20) 121.7(4) C(28)-C(25)-C(26) 108.5(4)

C(7)-C(8)-C(20) 119.3(4) C(28)-C(25)-C(27) 106.7(4)

C(10)-C(9)-C(8) 121.5(5) C(26)-C(25)-C(27) 108.2(4)

C(11)-C(10)-C(9) 119.6(5) C(28)-C(25)-P(2) 108.4(3)

C(10)-C(11)-C(12) 120.0(5) C(26)-C(25)-P(2) 112.3(3)

C(11)-C(12)-C(7) 121.1(5) C(27)-C(25)-P(2) 112.4(3)

C(14)-C(13)-C(18) 119.5(5) C(31)-C(29)-C(30) 106.5(4)

C(14)-C(13)-C(2) 120.4(4) C(31)-C(29)-C(32) 108.2(4)

C(18)-C(13)-C(2) 119.2(4) C(30)-C(29)-C(32) 110.2(4)

231 C(31)-C(29)-P(1) 108.8(3) C(33)-P(1)-Pd(1) 119.62(16)

C(30)-C(29)-P(1) 115.4(4) C(20)-P(2)-C(21) 104.9(2)

C(32)-C(29)-P(1) 107.4(3) C(20)-P(2)-C(25) 102.6(2)

C(34)-C(33)-C(35) 107.7(4) C(21)-P(2)-C(25) 108.4(2)

C(34)-C(33)-C(36) 108.6(4) C(20)-P(2)-Pd(1) 109.70(15)

C(35)-C(33)-C(36) 107.6(4) C(21)-P(2)-Pd(1) 108.88(15)

C(34)-C(33)-P(1) 112.7(4) C(25)-P(2)-Pd(1) 121.08(14)

C(35)-C(33)-P(1) 112.9(3) C(1)-Pd(1)-P(1) 88.75(13)

C(36)-C(33)-P(1) 107.2(3) C(1)-Pd(1)-P(2) 91.13(13)

C(19)-P(1)-C(29) 103.9(2) P(1)-Pd(1)-P(2) 178.85(4)

C(19)-P(1)-C(33) 102.0(2) C(1)-Pd(1)-Br(1) 177.05(13)

C(29)-P(1)-C(33) 109.6(2) P(1)-Pd(1)-Br(1) 90.28(3)

C(19)-P(1)-Pd(1) 110.80(15) P(2)-Pd(1)-Br(1) 89.89(3)

C(29)-P(1)-Pd(1) 109.69(16)

232 A7. Crystallographic Data for Compound 4.11.

I N

Figure A6. An ORTEP drawing (40% probability thermal ellipsoids) of 4.11 with atom labeling scheme.

Table A11. Crystal Data and Structure Refinement for 4.11.

Complex 4.11 • CHCl3

Empirical formula C33H24Cl3IN2Pd

Formula weight 788.19

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

Space group P2(1)/n

233 Unit cell dimensions a = 12.110(1) Å α = 90.00°

b = 14.012(1) Å β = 107.876(2)°

c = 18.952(2) Å γ = 90.00°

Vo l u me ( Å 3) 3060.6(5)

Z 4

Density (calcd g/cm3) 1.711

Absorption coeff. (mm-1) 1.903

F(000) 1544

Crystal size (mm) 0.19 x 0.14 x 0.15

Crystal color & shape Colorless block

θ range data collection 1.78-28.28

Limiting indices -16 < h < 16 -18 < k < 18 -25 < l < 25

Reflections collected 31328

Independent reflections 7604 (Rint = 0.0205)

Refinement method Full-matrix least- squares on F2

Data/restraint/parameters 7604/0/361

Goodness-of-fit on F2 1.118

Final R indices [I>2σ(I)] R1 = 0.0266 wR2 = 0.0615

R indices (all data) R1 = 0.0276 wR2 = 0.0621

234 Table A12. Bond lengths (Å) and angles (°) for 4.11.

I(1)-Pd(1) 2.7024(3) C(27)-C(32) 1.390(3)

Pd(1)-C(19) 1.971(2) C(29)-C(30) 1.381(4)

Pd(1)-N(2) 2.0232(18) C(6)-C(1) 1.379(4)

Pd(1)-N(1) 2.0246(19) C(6)-C(5) 1.383(3)

C(8)-C(9) 1.403(3) C(6)-N(1) 1.438(3)

C(8)-C(13) 1.412(3) C(32)-C(31) 1.389(3)

C(8)-C(7) 1.471(3) C(31)-C(30) 1.386(4)

N(2)-C(26) 1.282(3) C(23)-C(22) 1.390(3)

N(2)-C(27) 1.439(3) C(5)-C(4) 1.396(4)

C(28)-C(27) 1.385(3) C(1)-C(2) 1.388(4)

C(28)-C(29) 1.390(3) C(4)-C(3) 1.375(5)

C(21)-C(22) 1.388(3) C(2)-C(3) 1.380(4)

C(21)-C(20) 1.400(3) C(14)-C(15) 1.404(3)

C(11)-C(10) 1.382(4) C(14)-C(19) 1.407(3)

C(11)-C(12) 1.393(4) C(19)-C(18) 1.400(3)

C(13)-C(12) 1.396(3) C(18)-C(17) 1.402(3)

C(13)-C(14) 1.496(3) C(7)-N(1) 1.278(3)

C(20)-C(25) 1.413(3) C(17)-C(16) 1.382(3)

C(20)-C(18) 1.495(3) C(15)-C(16) 1.388(3)

C(25)-C(24) 1.397(3) Cl(1)-C(33) 1.762(3)

C(25)-C(26) 1.473(3) Cl(3)-C(33) 1.764(3)

C(24)-C(23) 1.387(3) Cl(2)-C(33) 1.765(3)

C(10)-C(9) 1.381(4)

235 C(19)-Pd(1)-N(2) 87.04(8) C(23)-C(24)-C(25) 121.0(2)

C(19)-Pd(1)-N(1) 87.19(8) C(9)-C(10)-C(11) 119.8(2)

N(2)-Pd(1)-N(1) 174.15(7) C(28)-C(27)-C(32) 120.8(2)

C(19)-Pd(1)-I(1) 173.56(7) C(28)-C(27)-N(2) 121.6(2)

N(2)-Pd(1)-I(1) 95.01(5) C(32)-C(27)-N(2) 117.6(2)

N(1)-Pd(1)-I(1) 90.83(5) C(11)-C(12)-C(13) 122.1(2)

C(9)-C(8)-C(13) 120.2(2) C(30)-C(29)-C(28) 120.4(2)

C(9)-C(8)-C(7) 116.2(2) N(2)-C(26)-C(25) 124.5(2)

C(13)-C(8)-C(7) 123.5(2) C(1)-C(6)-C(5) 120.8(2)

C(26)-N(2)-C(27) 118.60(18) C(1)-C(6)-N(1) 117.9(2)

C(26)-N(2)-Pd(1) 122.73(15) C(5)-C(6)-N(1) 121.3(2)

C(27)-N(2)-Pd(1) 118.65(14) C(31)-C(32)-C(27) 119.0(2)

C(27)-C(28)-C(29) 119.4(2) C(30)-C(31)-C(32) 120.6(3)

C(22)-C(21)-C(20) 122.0(2) C(24)-C(23)-C(22) 119.2(2)

C(10)-C(11)-C(12) 119.8(2) C(10)-C(9)-C(8) 120.8(2)

C(12)-C(13)-C(8) 117.4(2) C(21)-C(22)-C(23) 120.1(2)

C(12)-C(13)-C(14) 117.7(2) C(6)-C(5)-C(4) 118.9(3)

C(8)-C(13)-C(14) 124.9(2) C(6)-C(1)-C(2) 119.6(3)

C(21)-C(20)-C(25) 117.3(2) C(3)-C(4)-C(5) 120.6(3)

C(21)-C(20)-C(18) 118.0(2) C(3)-C(2)-C(1) 120.3(3)

C(25)-C(20)-C(18) 124.6(2) C(29)-C(30)-C(31) 119.8(2)

C(24)-C(25)-C(20) 120.4(2) C(4)-C(3)-C(2) 119.8(3)

C(24)-C(25)-C(26) 115.36(19) C(15)-C(14)-C(19) 119.4(2)

C(20)-C(25)-C(26) 124.0(2) C(15)-C(14)-C(13) 118.7(2)

236 C(19)-C(14)-C(13) 121.9(2) C(7)-N(1)-Pd(1) 120.60(16)

C(18)-C(19)-C(14) 120.4(2) C(6)-N(1)-Pd(1) 118.99(15)

C(18)-C(19)-Pd(1) 121.28(16) C(16)-C(17)-C(18) 121.1(2)

C(14)-C(19)-Pd(1) 118.35(16) C(16)-C(15)-C(14) 120.2(2)

C(19)-C(18)-C(17) 118.9(2) C(17)-C(16)-C(15) 120.1(2)

C(19)-C(18)-C(20) 122.48(19) Cl(1)-C(33)-Cl(3) 110.19(14)

C(17)-C(18)-C(20) 118.6(2) Cl(1)-C(33)-Cl(2) 110.97(13)

N(1)-C(7)-C(8) 122.9(2) Cl(3)-C(33)-Cl(2) 108.78(14)

C(7)-N(1)-C(6) 120.3(2)

237 A8. Crystallographic Data for Compound 4.12.

I N

Figure A7. An ORTEP drawing (40% probability thermal ellipsoids) of 4.12 with atom labeling scheme.

Table A13. Crystal Data and Structure Refinement for 4.12.

Complex 4.12

Empirical formula C36H31N2IPd

Formula weight 724.93

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

Space group P2(1)/c

238 Unit cell dimensions a = 17.3546(4) Å α = 90.00°

b = 14.2975(4) Å β = 99.881(1)°

c = 12.2046(3) Å γ = 90.00°

Vo l u me ( Å 3) 2983.4 (1)

Z 4

Density (calcd g/cm3) 1.614

Absorption coeff. (mm-1) 1.684

F(000) 1440

Crystal size (mm) 0.13 x 0.12 x 0.12

Crystal color & shape Colorless block

θ range data collection 1.19-27.50

Limiting indices -22 < h < 22 -18 < k < 18 -15 < l < 15

Reflections collected 42236

Independent reflections 6849 (Rint = 0.0309)

Refinement method Full-matrix least- squares on F2

Data/restraint/parameters 6849/0/365

Goodness-of-fit on F2 1.062

Final R indices [I>2σ(I)] R1 = 0.0212 wR2 = 0.0540

R indices (all data) R1 = 0.0251 wR2 = 0.0563

239 Table A14. Bond lengths (Å) and angles (°) for 4.12.

Pd(1)-C(1) 2.005(2) C(14)-C(19) 1.397(3)

Pd(1)-N(2) 2.0547(17) C(14)-C(15) 1.404(3)

Pd(1)-N(1) 2.0549(17) C(15)-C(16) 1.399(3)

Pd(1)-I(1) 2.7089(2) C(15)-C(21) 1.508(3)

N(1)-C(13) 1.278(3) C(16)-C(17) 1.381(3)

N(1)-C(14) 1.455(2) C(17)-C(18) 1.389(3)

N(2)-C(28) 1.286(3) C(18)-C(19) 1.393(3)

N(2)-C(29) 1.461(2) C(19)-C(20) 1.501(3)

C(1)-C(6) 1.405(3) C(22)-C(23) 1.398(3)

C(1)-C(2) 1.408(3) C(22)-C(27) 1.402(3)

C(2)-C(3) 1.403(3) C(23)-C(24) 1.384(3)

C(2)-C(22) 1.490(3) C(24)-C(25) 1.386(3)

C(3)-C(4) 1.382(3) C(25)-C(26) 1.389(3)

C(4)-C(5) 1.389(3) C(26)-C(27) 1.404(3)

C(5)-C(6) 1.405(3) C(27)-C(28) 1.466(3)

C(6)-C(7) 1.495(3) C(29)-C(34) 1.402(3)

C(7)-C(8) 1.398(3) C(29)-C(30) 1.404(3)

C(7)-C(12) 1.405(3) C(30)-C(31) 1.393(3)

C(8)-C(9) 1.386(3) C(30)-C(36) 1.498(3)

C(9)-C(10) 1.388(3) C(31)-C(32) 1.384(3)

C(10)-C(11) 1.381(3) C(32)-C(33) 1.388(3)

C(11)-C(12) 1.400(3) C(33)-C(34) 1.399(3)

C(12)-C(13) 1.466(3) C(34)-C(35) 1.512(3)

240 C(1)-C(6)-C(7) 124.04(18)

C(1)-Pd(1)-N(2) 88.97(7) C(8)-C(7)-C(12) 117.45(18)

C(1)-Pd(1)-N(1) 88.48(7) C(8)-C(7)-C(6) 119.11(18)

N(2)-Pd(1)-N(1) 177.39(6) C(12)-C(7)-C(6) 123.27(18)

C(1)-Pd(1)-I(1) 179.24(5) C(9)-C(8)-C(7) 122.0(2)

N(2)-Pd(1)-I(1) 90.35(4) C(8)-C(9)-C(10) 120.1(2)

N(1)-Pd(1)-I(1) 92.20(4) C(11)-C(10)-C(9) 119.0(2)

C(13)-N(1)-C(14) 114.87(17) C(10)-C(11)-C(12) 121.3(2)

C(13)-N(1)-Pd(1) 123.28(14) C(11)-C(12)-C(7) 120.07(19)

C(14)-N(1)-Pd(1) 121.40(13) C(11)-C(12)-C(13) 114.14(18)

C(28)-N(2)-C(29) 113.74(17) C(7)-C(12)-C(13) 125.77(18)

C(28)-N(2)-Pd(1) 123.23(14) N(1)-C(13)-C(12) 126.48(18)

C(29)-N(2)-Pd(1) 122.57(13) C(19)-C(14)-C(15) 122.18(18)

C(6)-C(1)-C(2) 118.68(18) C(19)-C(14)-N(1) 118.65(18)

C(6)-C(1)-Pd(1) 121.05(14) C(15)-C(14)-N(1) 119.13(18)

C(2)-C(1)-Pd(1) 120.27(15) C(16)-C(15)-C(14) 117.3(2)

C(3)-C(2)-C(1) 119.81(18) C(16)-C(15)-C(21) 118.83(19)

C(3)-C(2)-C(22) 115.46(17) C(14)-C(15)-C(21) 123.81(19)

C(1)-C(2)-C(22) 124.72(18) C(17)-C(16)-C(15) 121.4(2)

C(4)-C(3)-C(2) 121.36(19) C(16)-C(17)-C(18) 120.00(19)

C(3)-C(4)-C(5) 119.12(19) C(17)-C(18)-C(19) 120.7(2)

C(4)-C(5)-C(6) 120.74(19) C(18)-C(19)-C(14) 118.29(19)

C(5)-C(6)-C(1) 120.23(18) C(18)-C(19)-C(20) 120.14(19)

C(5)-C(6)-C(7) 115.71(18) C(14)-C(19)-C(20) 121.53(18)

241 C(23)-C(22)-C(27) 117.70(18) C(34)-C(29)-N(2) 119.60(17)

C(23)-C(22)-C(2) 118.29(18) C(30)-C(29)-N(2) 118.62(17)

C(27)-C(22)-C(2) 123.56(18) C(31)-C(30)-C(29) 118.03(19)

C(24)-C(23)-C(22) 121.9(2) C(31)-C(30)-C(36) 120.07(19)

C(23)-C(24)-C(25) 120.2(2) C(29)-C(30)-C(36) 121.90(18)

C(24)-C(25)-C(26) 119.1(2) C(32)-C(31)-C(30) 121.4(2)

C(25)-C(26)-C(27) 120.8(2) C(31)-C(32)-C(33) 119.71(19)

C(22)-C(27)-C(26) 120.17(19) C(32)-C(33)-C(34) 121.1(2)

C(22)-C(27)-C(28) 125.47(18) C(33)-C(34)-C(29) 117.98(19)

C(26)-C(27)-C(28) 114.26(18) C(33)-C(34)-C(35) 117.85(19)

N(2)-C(28)-C(27) 126.89(18) C(29)-C(34)-C(35) 124.17(19)

C(34)-C(29)-C(30) 121.73(18)

242 A9. Crystallographic Data for Compound 4.13.

I N

Figure A8. An ORTEP drawing (40% probability thermal ellipsoids) of 4.13 with atom labeling scheme.

Table A15. Crystal Data and Structure Refinement for 4.13.

Complex 4.13

Empirical formula C38H35N2IPd

Formula weight 752.98

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

243 Space group C2/c

Unit cell dimensions a = 27.4660(8) Å α = 90.00°

b = 13.7460(4) Å β = 121.316(1)°

c = 19.5017(6) Å γ = 90.00°

Vo l u me ( Å 3) 6290.2 (3)

Z 8

Density (calcd g/cm3) 1.590

Absorption coeff. (mm-1) 1.601

F(000) 3008

Crystal size (mm) 0.35 x 0.25 x 0.20

Crystal color & shape Colorless block

θ range data collection 1.72-27.50

Limiting indices -34 < h < 35 -17 < k < 17 -25 < l < 25

Reflections collected 31842

Independent reflections 7193 (Rint = 0.0174)

Refinement method Full-matrix least- squares on F2

Data/restraint/parameters 7193/0/386

Goodness-of-fit on F2 1.090

Final R indices [I>2σ(I)] R1 = 0.0165 wR2 = 0.0459

R indices (all data) R1 = 0.0180 wR2 = 0.0469

244 Table A16. Bond lengths (Å) and angles (°) for 4.13.

C(1)-C(2) 1.404(2) C(17)-C(18) 1.391(3)

C(1)-C(6) 1.410(2) C(17)-C(21) 1.507(2)

C(1)-Pd(1) 2.0105(15) C(18)-C(19) 1.394(2)

C(2)-C(3) 1.404(2) C(19)-C(20) 1.506(2)

C(2)-C(23) 1.493(2) C(23)-C(28) 1.401(2)

C(3)-C(4) 1.384(2) C(23)-C(24) 1.401(2)

C(4)-C(5) 1.385(2) C(24)-C(25) 1.387(2)

C(6)-C(5) 1.404(2) C(25)-C(26) 1.389(2)

C(6)-C(7) 1.491(2) C(26)-C(27) 1.384(2)

C(7)-C(8) 1.400(2) C(27)-C(28) 1.401(2)

C(7)-C(12) 1.401(2) C(28)-C(29) 1.469(2)

C(8)-C(9) 1.385(2) C(29)-N(1) 1.2835(19)

C(9)-C(10) 1.385(3) C(30)-C(35) 1.395(2)

C(10)-C(11) 1.383(3) C(30)-C(31) 1.411(2)

C(11)-C(12) 1.405(2) C(30)-N(1) 1.4514(19)

C(12)-C(13) 1.471(2) C(31)-C(32) 1.392(2)

C(13)-N(2) 1.281(2) C(31)-C(38) 1.512(2)

C(14)-C(15) 1.395(2) C(32)-C(33) 1.392(2)

C(14)-C(19) 1.410(2) C(33)-C(34) 1.389(2)

C(14)-N(2) 1.4505(19) C(33)-C(37) 1.510(2)

C(15)-C(16) 1.397(2) C(34)-C(35) 1.398(2)

C(15)-C(22) 1.496(2) C(35)-C(36) 1.506(2)

C(16)-C(17) 1.386(3) I(1)-Pd(1) 2.71613(15)

245 N(2)-Pd(1) 2.0550(13) N(2)-C(13)-C(12) 125.62(14)

N(1)-Pd(1) 2.0514(12) C(15)-C(14)-C(19) 121.77(15)

C(15)-C(14)-N(2) 119.21(14)

C(2)-C(1)-C(6) 118.34(13) C(19)-C(14)-N(2) 119.01(14)

C(2)-C(1)-Pd(1) 121.53(11) C(14)-C(15)-C(16) 118.02(16)

C(6)-C(1)-Pd(1) 120.10(11) C(14)-C(15)-C(22) 122.13(15)

C(3)-C(2)-C(1) 120.39(14) C(16)-C(15)-C(22) 119.86(16)

C(3)-C(2)-C(23) 115.84(13) C(17)-C(16)-C(15) 122.05(17)

C(1)-C(2)-C(23) 123.74(13) C(16)-C(17)-C(18) 118.40(16)

C(4)-C(3)-C(2) 120.82(14) C(16)-C(17)-C(21) 121.28(18)

C(3)-C(4)-C(5) 119.38(14) C(18)-C(17)-C(21) 120.32(18)

C(5)-C(6)-C(1) 120.17(14) C(17)-C(18)-C(19) 122.21(17)

C(5)-C(6)-C(7) 116.01(13) C(18)-C(19)-C(14) 117.53(15)

C(1)-C(6)-C(7) 123.77(13) C(18)-C(19)-C(20) 118.77(15)

C(8)-C(7)-C(12) 117.60(14) C(14)-C(19)-C(20) 123.70(14)

C(8)-C(7)-C(6) 117.90(14) C(28)-C(23)-C(24) 117.58(14)

C(12)-C(7)-C(6) 124.35(13) C(28)-C(23)-C(2) 123.31(14)

C(9)-C(8)-C(7) 121.71(16) C(24)-C(23)-C(2) 118.90(14)

C(8)-C(9)-C(10) 120.26(16) C(25)-C(24)-C(23) 121.65(15)

C(11)-C(10)-C(9) 119.33(16) C(24)-C(25)-C(26) 120.39(15)

C(10)-C(11)-C(12) 120.63(16) C(27)-C(26)-C(25) 118.77(15)

C(7)-C(12)-C(11) 120.37(14) C(26)-C(27)-C(28) 121.11(15)

C(7)-C(12)-C(13) 124.36(13) C(23)-C(28)-C(27) 120.33(14)

C(11)-C(12)-C(13) 115.19(14) C(23)-C(28)-C(29) 125.96(14)

246 C(27)-C(28)-C(29) 113.70(13) C(34)-C(35)-C(36) 119.69(14)

N(1)-C(29)-C(28) 126.23(14) C(4)-C(5)-C(6) 120.86(14)

C(35)-C(30)-C(31) 121.18(14) C(13)-N(2)-C(14) 115.22(13)

C(35)-C(30)-N(1) 120.20(13) C(13)-N(2)-Pd(1) 122.61(11)

C(31)-C(30)-N(1) 118.52(13) C(14)-N(2)-Pd(1) 121.46(10)

C(32)-C(31)-C(30) 117.69(15) C(29)-N(1)-C(30) 115.24(13)

C(32)-C(31)-C(38) 118.53(14) C(29)-N(1)-Pd(1) 123.20(11)

C(30)-C(31)-C(38) 123.69(14) C(30)-N(1)-Pd(1) 120.94(9)

C(33)-C(32)-C(31) 122.78(15) C(1)-Pd(1)-N(1) 89.56(5)

C(34)-C(33)-C(32) 117.74(15) C(1)-Pd(1)-N(2) 88.49(5)

C(34)-C(33)-C(37) 121.74(16) N(1)-Pd(1)-N(2) 177.89(5)

C(32)-C(33)-C(37) 120.51(16) C(1)-Pd(1)-I(1) 178.10(4)

C(33)-C(34)-C(35) 122.07(16) N(1)-Pd(1)-I(1) 90.07(3)

C(30)-C(35)-C(34) 118.48(15) N(2)-Pd(1)-I(1) 91.86(3)

C(30)-C(35)-C(36) 121.80(14)

247 A10. Crystallographic Data for Compound 4.14.

I N

Figure A9. An ORTEP drawing (40% probability thermal ellipsoids) of 4.14 with atom labeling scheme.

Table A17. Crystal Data and Structure Refinement for 4.14.

Complex 4.14

Empirical formula C32H35N2IPd

Formula weight 680.92

Temperature (K) 100

Wavelength (Å) 0.71073

248 Crystal system Triclinic

Space group P-1

Unit cell dimensions a = 9.7013(2) Å α = 88.357(1)°

b = 10.4575(2) Å β = 85.110(1)°

c = 14.4524(3) Å γ = 73.893(1)°

Vo l u me ( Å 3) 1403.51(5)

Z 2

Density (calcd g/cm3) 1.611

Absorption coeff. (mm-1) 1.784

F(000) 680

Crystal size (mm) 0.20 x 0.15 x 0.15

Crystal color & shape Colorless block

θ range data collection 2.03-27.50

Limiting indices -12 < h < 12 -13 < k < 13 -18 < l < 18

Reflections collected 22801

Independent reflections 6411 (Rint = 0.0174)

Refinement method Full-matrix least- squares on F2

Data/restraint/parameters 6411/0/325

Goodness-of-fit on F2 1.169

Final R indices [I>2σ(I)] R1 = 0.0237 wR2 = 0.0600

R indices (all data) R1 = 0.0251 wR2 = 0.0607

249 Table A18. Bond lengths (Å) and angles (°) for 4.14.

Pd(1)-C(1) 1.980(3) C(25)-C(26) 1.480(4)

Pd(1)-N(2) 2.034(2) C(2)-C(3) 1.404(4)

Pd(1)-N(1) 2.033(2) C(24)-C(23) 1.389(4)

Pd(1)-I(1) 2.7139(3) C(15)-C(16) 1.535(4)

N(1)-C(13) 1.276(4) C(22)-C(21) 1.389(4)

N(1)-C(14) 1.493(3) C(22)-C(23) 1.387(4)

C(1)-C(2) 1.402(4) C(26)-N(2) 1.273(4)

C(1)-C(6) 1.408(4) C(11)-C(10) 1.390(4)

C(14)-C(19) 1.521(4) C(19)-C(18) 1.529(4)

C(14)-C(15) 1.528(4) C(3)-C(4) 1.388(4)

C(27)-N(2) 1.486(3) C(28)-C(29) 1.536(4)

C(27)-C(32) 1.521(4) C(4)-C(5) 1.390(5)

C(27)-C(28) 1.520(4) C(29)-C(30) 1.510(4)

C(20)-C(21) 1.398(4) C(32)-C(31) 1.532(4)

C(20)-C(25) 1.407(4) C(8)-C(9) 1.381(5)

C(20)-C(2) 1.492(4) C(17)-C(18) 1.523(4)

C(12)-C(11) 1.394(4) C(17)-C(16) 1.525(4)

C(12)-C(7) 1.404(4) C(30)-C(31) 1.523(4)

C(12)-C(13) 1.479(4) C(10)-C(9) 1.389(5)

C(6)-C(5) 1.398(4)

C(6)-C(7) 1.493(4) C(1)-Pd(1)-N(2) 87.72(10)

C(7)-C(8) 1.408(4) C(1)-Pd(1)-N(1) 86.57(10)

C(25)-C(24) 1.399(4) N(2)-Pd(1)-N(1) 173.94(9)

250 C(1)-Pd(1)-I(1) 175.60(8) C(8)-C(7)-C(12) 118.0(3)

N(2)-Pd(1)-I(1) 92.92(6) C(8)-C(7)-C(6) 118.7(3)

N(1)-Pd(1)-I(1) 92.93(6) C(12)-C(7)-C(6) 123.4(2)

C(13)-N(1)-C(14) 121.4(2) C(24)-C(25)-C(20) 120.2(2)

C(13)-N(1)-Pd(1) 120.87(18) C(24)-C(25)-C(26) 114.6(2)

C(14)-N(1)-Pd(1) 117.63(16) C(20)-C(25)-C(26) 125.2(2)

C(2)-C(1)-C(6) 119.5(2) N(1)-C(13)-C(12) 124.1(2)

C(2)-C(1)-Pd(1) 119.0(2) C(3)-C(2)-C(1) 119.8(3)

C(6)-C(1)-Pd(1) 121.3(2) C(3)-C(2)-C(20) 118.4(3)

N(1)-C(14)-C(19) 108.4(2) C(1)-C(2)-C(20) 121.7(2)

N(1)-C(14)-C(15) 115.6(2) C(23)-C(24)-C(25) 120.7(3)

C(19)-C(14)-C(15) 110.8(2) C(14)-C(15)-C(16) 110.0(2)

N(2)-C(27)-C(32) 109.3(2) C(21)-C(22)-C(23) 119.8(3)

N(2)-C(27)-C(28) 115.1(2) N(2)-C(26)-C(25) 123.9(2)

C(32)-C(27)-C(28) 111.4(2) C(10)-C(11)-C(12) 121.0(3)

C(21)-C(20)-C(25) 117.7(3) C(14)-C(19)-C(18) 110.8(2)

C(21)-C(20)-C(2) 118.3(2) C(4)-C(3)-C(2) 120.5(3)

C(25)-C(20)-C(2) 124.0(2) C(27)-C(28)-C(29) 110.3(2)

C(11)-C(12)-C(7) 120.0(3) C(3)-C(4)-C(5) 119.8(3)

C(11)-C(12)-C(13) 116.7(3) C(4)-C(5)-C(6) 120.7(3)

C(7)-C(12)-C(13) 123.1(3) C(22)-C(21)-C(20) 122.0(3)

C(5)-C(6)-C(1) 119.7(3) C(30)-C(29)-C(28) 112.0(3)

C(5)-C(6)-C(7) 119.4(3) C(27)-C(32)-C(31) 110.7(3)

C(1)-C(6)-C(7) 120.9(2) C(24)-C(23)-C(22) 119.5(3)

251 C(9)-C(8)-C(7) 121.4(3) C(8)-C(9)-C(10) 120.2(3)

C(18)-C(17)-C(16) 110.4(3) C(30)-C(31)-C(32) 111.0(3)

C(17)-C(16)-C(15) 112.0(2) C(26)-N(2)-C(27) 121.5(2)

C(29)-C(30)-C(31) 111.0(3) C(26)-N(2)-Pd(1) 121.47(18)

C(11)-C(10)-C(9) 119.2(3) C(27)-N(2)-Pd(1) 116.81(16)

C(17)-C(18)-C(19) 111.3(3)

252 A11. Crystallographic Data for Compound 5.9.

NMe NMe 2 2

Figure A10. An ORTEP drawing (40% probability thermal ellipsoids) of 5.9 with atom labeling scheme.

Table A19. Crystal Data and Structure Refinement for 5.9.

Complex 5.9

Empirical formula C24H27IN2

Formula weight 470.38

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

Space group P2(1)/c

253 Unit cell dimensions a = 16.2484 α = 90.00

b = 16.8777(3) β = 101.108(1)

c = 7.8974(1) γ = 90.00

Vo l u me ( Å 3) 2125.17(6)

Z 4

Density (calcd. g/cm3) 1.470

Absorption coeff. (mm-1) 1.517

F(000) 952

Crystal size (mm) 0.12×0.08×0.06

Crystal color & shape Colorless block

θ range data collection 1.28-28.29

Limiting indices -21< h <21 -22< k <22 -10< l <10

Reflections collected 35762

Independent reflections 5274(Rint = 0.0591)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 5274/0/248

Goodness-of-fit on F2 1.109

Final R indices [I>2σ(I)]a,b R1 = 0.0303 wR2 = 0.0657

R indices (all data) R1 = 0.0491 wR2 = 0.0836

254 Table A20. Bond lengths (Å) and angles (°) for 5.9.

I(1)-C(1) 2.102(3) C(19)-N(1) 1.464(3)

C(5)-C(4) 1.386(4) C(20)-N(2) 1.464(3)

C(5)-C(6) 1.395(4) C(23)-N(2) 1.460(4)

C(1)-C(6) 1.402(4) C(24)-N(2) 1.458(4)

C(1)-C(2) 1.405(4) C(21)-N(1) 1.458(4)

C(4)-C(3) 1.387(4) C(22)-N(1) 1.459(4)

C(6)-C(7) 1.491(4)

C(2)-C(3) 1.392(4) C(4)-C(5)-C(6) 120.9(3)

C(2)-C(13) 1.502(4) C(6)-C(1)-C(2) 121.8(3)

C(11)-C(10) 1.381(4) C(6)-C(1)-I(1) 119.2(2)

C(11)-C(12) 1.389(4) C(2)-C(1)-I(1) 119.00(19)

C(7)-C(12) 1.394(4) C(5)-C(4)-C(3) 120.1(3)

C(7)-C(8) 1.409(4) C(5)-C(6)-C(1) 118.1(3)

C(9)-C(10) 1.387(4) C(5)-C(6)-C(7) 119.2(2)

C(9)-C(8) 1.393(4) C(1)-C(6)-C(7) 122.8(2)

C(8)-C(19) 1.510(4) C(3)-C(2)-C(1) 118.0(2)

C(13)-C(18) 1.394(4) C(3)-C(2)-C(13) 119.4(2)

C(13)-C(14) 1.407(4) C(1)-C(2)-C(13) 122.6(2)

C(14)-C(15) 1.397(4) C(4)-C(3)-C(2) 121.0(3)

C(14)-C(20) 1.513(4) C(10)-C(11)-C(12) 119.6(3)

C(15)-C(16) 1.391(4) C(12)-C(7)-C(8) 119.4(3)

C(17)-C(16) 1.379(4) C(12)-C(7)-C(6) 119.6(2)

C(17)-C(18) 1.389(4) C(8)-C(7)-C(6) 120.9(3)

255 C(10)-C(9)-C(8) 121.6(3) C(16)-C(15)-C(14) 120.7(3)

C(11)-C(10)-C(9) 119.8(3) C(16)-C(17)-C(18) 119.9(3)

C(11)-C(12)-C(7) 121.1(3) C(17)-C(16)-C(15) 120.3(3)

C(9)-C(8)-C(7) 118.4(3) C(17)-C(18)-C(13) 120.3(3)

C(9)-C(8)-C(19) 120.2(2) N(1)-C(19)-C(8) 112.7(2)

C(7)-C(8)-C(19) 121.3(3) N(2)-C(20)-C(14) 113.9(2)

C(18)-C(13)-C(14) 120.1(3) C(24)-N(2)-C(23) 109.2(2)

C(18)-C(13)-C(2) 119.1(3) C(24)-N(2)-C(20) 110.5(2)

C(14)-C(13)-C(2) 120.9(2) C(23)-N(2)-C(20) 109.2(2)

C(15)-C(14)-C(13) 118.6(3) C(21)-N(1)-C(22) 110.1(2)

C(15)-C(14)-C(20) 120.9(3) C(21)-N(1)-C(19) 110.7(2)

C(13)-C(14)-C(20) 120.5(2) C(22)-N(1)-C(19) 111.0(2)

256 A12. Crystallographic Data for Compound 5.10.

N I

Figure A11. An ORTEP drawing (30% probability thermal ellipsoids) of 5.10 with atom labeling scheme. Only one of the four independent molecules in the asymmetric unit is shown.

Table A21. Crystal Data and Structure Refinement for 5.10.

Complex 5.10

Empirical formula C24H27IN2Pd

Formula weight 576.78

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Triclinic

Space group P-1

Unit cell dimensions a = 15.4830(2) α = 74.624(1)

b = 15.6181(2) β = 76.617(1)

c = 19.6522(3) γ = 89.867(1)

257 Vo l u me ( Å 3) 4448.8(1)

Z 8

Density (calcd. g/cm3) 1.722

Absorption coeff. (mm-1) 2.234

F(000) 2272

Crystal size (mm) 0.06×0.30×0.33

Crystal color & shape Light yellow plate

θ range data collection 1.11-28.33

Limiting indices -20< h <20 -20< k <20 -26< l <26

Reflections collected 118856

Independent reflections 22093(Rint= 0.0336)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 22093/0/1025

Goodness-of-fit on F2 1.147

Final R indices [I>2σ(I)]a,b R1 = 0.0348 wR2 = 0.0794

R indices (all data) R1 = 0.0471 wR2 = 0.0852

258 Table A22. Bond lengths (Å) and angles (°) for 5.10.

Pd(1)-C(1) 1.995(4) N(1B)-C(22B) 1.498(5)

Pd(1)-N(1) 2.121(3) N(1B)-C(19B) 1.500(5)

Pd(1)-N(2) 2.167(3) N(2B)-C(24B) 1.490(5)

Pd(1)-I(1) 2.8018(4) N(2B)-C(23B) 1.491(5)

Pd(1B)-C(1B) 1.995(4) N(2B)-C(20B) 1.501(5)

Pd(1B)-N(1B) 2.126(3) N(1C)-C(21C) 1.481(5)

Pd(1B)-N(2B) 2.167(3) N(1C)-C(22C) 1.487(5)

Pd(1B)-I(1B) 2.8170(4) N(1C)-C(19C) 1.511(5)

Pd(1C)-C(1C) 1.998(4) N(2C)-C(23C) 1.494(5)

Pd(1C)-N(1C) 2.118(3) N(2C)-C(24C) 1.496(6)

Pd(1C)-N(2C) 2.158(3) N(2C)-C(20C) 1.507(5)

Pd(1C)-I(1C) 2.8238(4) N(1D)-C(22D) 1.485(5)

Pd(1D)-C(1D) 1.994(4) N(1D)-C(21D) 1.490(5)

Pd(1D)-N(2D) 2.125(3) N(1D)-C(19D) 1.509(5)

Pd(1D)-N(1D) 2.162(3) N(2D)-C(23D) 1.489(5)

Pd(1D)-I(1D) 2.8199(4) N(2D)-C(24D) 1.492(5)

N(1)-C(22) 1.485(5) N(2D)-C(20D) 1.505(5)

N(1)-C(21) 1.492(5) C(1)-C(2) 1.402(6)

N(1)-C(19) 1.508(5) C(1)-C(6) 1.406(6)

N(2)-C(24) 1.489(5) C(2)-C(3) 1.409(5)

N(2)-C(23) 1.490(5) C(2)-C(13) 1.483(6)

N(2)-C(20) 1.505(5) C(3)-C(4) 1.377(6)

N(1B)-C(21B) 1.479(5) C(4)-C(5) 1.387(6)

259 C(5)-C(6) 1.401(6) C(7B)-C(12B) 1.388(6)

C(6)-C(7) 1.494(6) C(7B)-C(8B) 1.400(6)

C(7)-C(12) 1.386(6) C(8B)-C(9B) 1.399(6)

C(7)-C(8) 1.400(6) C(8B)-C(19B) 1.509(6)

C(8)-C(9) 1.398(6) C(9B)-C(10B) 1.394(8)

C(8)-C(19) 1.506(5) C(10B)-C(11B) 1.367(9)

C(9)-C(10) 1.381(6) C(11B)-C(12B) 1.395(7)

C(10)-C(11) 1.372(7) C(13B)-C(18B) 1.391(6)

C(11)-C(12) 1.396(7) C(13B)-C(14B) 1.408(6)

C(13)-C(18) 1.391(6) C(14B)-C(15B) 1.396(6)

C(13)-C(14) 1.417(6) C(14B)-C(20B) 1.501(6)

C(14)-C(15) 1.390(6) C(15B)-C(16B) 1.392(7)

C(14)-C(20) 1.510(6) C(16B)-C(17B) 1.364(7)

C(15)-C(16) 1.393(7) C(17B)-C(18B) 1.403(6)

C(16)-C(17) 1.386(7) C(1C)-C(2C) 1.405(5)

C(17)-C(18) 1.389(6) C(1C)-C(6C) 1.407(5)

C(1B)-C(6B) 1.400(5) C(2C)-C(3C) 1.400(5)

C(1B)-C(2B) 1.406(5) C(2C)-C(13C) 1.488(5)

C(2B)-C(3B) 1.393(5) C(3C)-C(4C) 1.389(6)

C(2B)-C(13B) 1.485(5) C(4C)-C(5C) 1.380(6)

C(3B)-C(4B) 1.382(6) C(5C)-C(6C) 1.399(5)

C(4B)-C(5B) 1.398(6) C(6C)-C(7C) 1.487(6)

C(5B)-C(6B) 1.394(5) C(7C)-C(12C) 1.401(6)

C(6B)-C(7B) 1.489(5) C(7C)-C(8C) 1.401(6)

260 C(8C)-C(9C) 1.397(6) C(9D)-C(10D) 1.396(7)

C(8C)-C(19C) 1.502(6) C(10D)-C(11D) 1.368(7)

C(9C)-C(10C) 1.379(7) C(11D)-C(12D) 1.389(6)

C(10C)-C(11C) 1.384(8) C(13D)-C(14D) 1.400(5)

C(11C)-C(12C) 1.385(7) C(13D)-C(18D) 1.400(6)

C(13C)-C(18C) 1.392(6) C(14D)-C(15D) 1.399(5)

C(13C)-C(14C) 1.406(6) C(14D)-C(20D) 1.505(6)

C(14C)-C(15C) 1.394(6) C(15D)-C(16D) 1.384(7)

C(14C)-C(20C) 1.502(7) C(16D)-C(17D) 1.379(7)

C(15C)-C(16C) 1.381(8) C(17D)-C(18D) 1.388(6)

C(16C)-C(17C) 1.372(8)

C(17C)-C(18C) 1.397(6) C(1)-Pd(1)-N(1) 88.76(14)

C(1D)-C(2D) 1.398(5) C(1)-Pd(1)-N(2) 86.75(14)

C(1D)-C(6D) 1.404(5) N(1)-Pd(1)-N(2) 171.31(13)

C(2D)-C(3D) 1.407(5) C(1)-Pd(1)-I(1) 160.72(12)

C(2D)-C(13D) 1.489(5) N(1)-Pd(1)-I(1) 91.72(9)

C(3D)-C(4D) 1.387(6) N(2)-Pd(1)-I(1) 94.98(9)

C(4D)-C(5D) 1.386(6) C(1B)-Pd(1B)-N(1B) 89.04(14)

C(5D)-C(6D) 1.399(5) C(1B)-Pd(1B)-N(2B) 86.36(14)

C(6D)-C(7D) 1.495(5) N(1B)-Pd(1B)-N(2B) 169.93(13)

C(7D)-C(12D) 1.394(6) C(1B)-Pd(1B)-I(1B) 159.27(11)

C(7D)-C(8D) 1.408(6) N(1B)-Pd(1B)-I(1B) 91.16(9)

C(8D)-C(9D) 1.386(6) N(2B)-Pd(1B)-I(1B) 96.31(9)

C(8D)-C(19D) 1.509(6) C(1C)-Pd(1C)-N(1C) 89.26(13)

261 C(1C)-Pd(1C)-N(2C) 86.64(14) C(21B)-N(1B)-C(19B) 107.0(3)

N(1C)-Pd(1C)-N(2C) 170.05(13) C(22B)-N(1B)-C(19B) 106.4(3)

C(1C)-Pd(1C)-I(1C) 160.05(11) C(21B)-N(1B)-Pd(1B) 109.3(3)

N(1C)-Pd(1C)-I(1C) 91.22(9) C(22B)-N(1B)-Pd(1B) 108.5(3)

N(2C)-Pd(1C)-I(1C) 95.73(9) C(19B)-N(1B)-Pd(1B) 116.4(2)

C(1D)-Pd(1D)-N(2D) 88.52(13) C(24B)-N(2B)-C(23B) 106.9(3)

C(1D)-Pd(1D)-N(1D) 86.55(14) C(24B)-N(2B)-C(20B) 108.9(3)

N(2D)-Pd(1D)-N(1D) 170.42(13) C(23B)-N(2B)-C(20B) 106.8(3)

C(1D)-Pd(1D)-I(1D) 161.50(11) C(24B)-N(2B)-Pd(1B) 108.3(3)

N(2D)-Pd(1D)-I(1D) 92.18(9) C(23B)-N(2B)-Pd(1B) 113.7(2)

N(1D)-Pd(1D)-I(1D) 95.11(9) C(20B)-N(2B)-Pd(1B) 112.0(2)

C(22)-N(1)-C(21) 109.5(3) C(21C)-N(1C)-C(22C) 109.7(3)

C(22)-N(1)-C(19) 107.1(3) C(21C)-N(1C)-C(19C) 106.9(3)

C(21)-N(1)-C(19) 106.2(3) C(22C)-N(1C)-C(19C) 105.9(3)

C(22)-N(1)-Pd(1) 109.2(2) C(21C)-N(1C)-Pd(1C) 110.0(3)

C(21)-N(1)-Pd(1) 109.0(2) C(22C)-N(1C)-Pd(1C) 108.6(2)

C(19)-N(1)-Pd(1) 115.7(2) C(19C)-N(1C)-Pd(1C) 115.6(2)

C(24)-N(2)-C(23) 107.0(3) C(23C)-N(2C)-C(24C) 106.8(3)

C(24)-N(2)-C(20) 107.3(3) C(23C)-N(2C)-C(20C) 107.2(3)

C(23)-N(2)-C(20) 108.8(3) C(24C)-N(2C)-C(20C) 109.5(3)

C(24)-N(2)-Pd(1) 114.5(3) C(23C)-N(2C)-Pd(1C) 114.1(2)

C(23)-N(2)-Pd(1) 108.1(2) C(24C)-N(2C)-Pd(1C) 107.3(3)

C(20)-N(2)-Pd(1) 110.9(2) C(20C)-N(2C)-Pd(1C) 111.7(3)

C(21B)-N(1B)-C(22B) 109.1(3) C(22D)-N(1D)-C(21D) 106.5(3)

262 C(22D)-N(1D)-C(19D) 107.4(3) C(12)-C(7)-C(6) 122.3(4)

C(21D)-N(1D)-C(19D) 109.0(3) C(8)-C(7)-C(6) 118.2(3)

C(22D)-N(1D)-Pd(1D) 114.6(2) C(9)-C(8)-C(7) 119.5(4)

C(21D)-N(1D)-Pd(1D) 107.8(2) C(9)-C(8)-C(19) 120.3(4)

C(19D)-N(1D)-Pd(1D) 111.4(2) C(7)-C(8)-C(19) 120.1(4)

C(23D)-N(2D)-C(24D) 109.4(3) C(10)-C(9)-C(8) 120.6(4)

C(23D)-N(2D)-C(20D) 106.4(3) C(11)-C(10)-C(9) 119.7(4)

C(24D)-N(2D)-C(20D) 107.3(3) C(10)-C(11)-C(12) 120.7(4)

C(23D)-N(2D)-Pd(1D) 108.6(2) C(7)-C(12)-C(11) 120.0(4)

C(24D)-N(2D)-Pd(1D) 109.2(2) C(18)-C(13)-C(14) 119.4(4)

C(20D)-N(2D)-Pd(1D) 115.8(2) C(18)-C(13)-C(2) 122.7(4)

C(2)-C(1)-C(6) 119.6(4) C(14)-C(13)-C(2) 117.9(4)

C(2)-C(1)-Pd(1) 114.4(3) C(15)-C(14)-C(13) 119.6(4)

C(6)-C(1)-Pd(1) 126.0(3) C(15)-C(14)-C(20) 121.8(4)

C(1)-C(2)-C(3) 119.5(4) C(13)-C(14)-C(20) 118.7(4)

C(1)-C(2)-C(13) 119.7(3) C(14)-C(15)-C(16) 120.7(4)

C(3)-C(2)-C(13) 120.7(4) C(17)-C(16)-C(15) 119.3(4)

C(4)-C(3)-C(2) 120.5(4) C(16)-C(17)-C(18) 121.1(4)

C(3)-C(4)-C(5) 120.4(4) C(17)-C(18)-C(13) 120.0(4)

C(4)-C(5)-C(6) 120.2(4) C(8)-C(19)-N(1) 112.9(3)

C(5)-C(6)-C(1) 119.7(4) N(2)-C(20)-C(14) 112.0(3)

C(5)-C(6)-C(7) 119.7(4) C(6B)-C(1B)-C(2B) 119.4(4)

C(1)-C(6)-C(7) 120.2(3) C(6B)-C(1B)-Pd(1B) 126.6(3)

C(12)-C(7)-C(8) 119.4(4) C(2B)-C(1B)-Pd(1B) 113.9(3)

263 C(3B)-C(2B)-C(1B) 119.9(4) C(13B)-C(14B)-C(20B) 117.8(4)

C(3B)-C(2B)-C(13B) 120.0(3) C(16B)-C(15B)-C(14B) 120.4(4)

C(1B)-C(2B)-C(13B) 120.1(3) C(17B)-C(16B)-C(15B) 120.3(4)

C(4B)-C(3B)-C(2B) 120.7(4) C(16B)-C(17B)-C(18B) 120.3(5)

C(3B)-C(4B)-C(5B) 119.6(4) C(13B)-C(18B)-C(17B) 120.4(4)

C(6B)-C(5B)-C(4B) 120.5(4) N(1B)-C(19B)-C(8B) 114.0(3)

C(5B)-C(6B)-C(1B) 119.8(4) N(2B)-C(20B)-C(14B) 112.7(3)

C(5B)-C(6B)-C(7B) 118.6(4) C(2C)-C(1C)-C(6C) 118.8(3)

C(1B)-C(6B)-C(7B) 121.3(4) C(2C)-C(1C)-Pd(1C) 114.6(3)

C(12B)-C(7B)-C(8B) 119.8(4) C(6C)-C(1C)-Pd(1C) 126.6(3)

C(12B)-C(7B)-C(6B) 121.6(4) C(3C)-C(2C)-C(1C) 120.6(4)

C(8B)-C(7B)-C(6B) 118.4(4) C(3C)-C(2C)-C(13C) 120.0(4)

C(9B)-C(8B)-C(7B) 119.6(4) C(1C)-C(2C)-C(13C) 119.3(3)

C(9B)-C(8B)-C(19B) 120.5(4) C(4C)-C(3C)-C(2C) 120.1(4)

C(7B)-C(8B)-C(19B) 119.8(4) C(5C)-C(4C)-C(3C) 119.6(4)

C(10B)-C(9B)-C(8B) 119.7(5) C(4C)-C(5C)-C(6C) 121.3(4)

C(11B)-C(10B)-C(9B) 120.4(5) C(5C)-C(6C)-C(1C) 119.6(4)

C(10B)-C(11B)-C(12B) 120.6(5) C(5C)-C(6C)-C(7C) 119.2(4)

C(7B)-C(12B)-C(11B) 119.9(5) C(1C)-C(6C)-C(7C) 120.9(3)

C(18B)-C(13B)-C(14B) 119.1(4) C(12C)-C(7C)-C(8C) 119.0(4)

C(18B)-C(13B)-C(2B) 121.9(4) C(12C)-C(7C)-C(6C) 121.8(4)

C(14B)-C(13B)-C(2B) 119.0(4) C(8C)-C(7C)-C(6C) 118.9(4)

C(15B)-C(14B)-C(13B) 119.5(4) C(9C)-C(8C)-C(7C) 119.2(4)

C(15B)-C(14B)-C(20B) 122.7(4) C(9C)-C(8C)-C(19C) 121.2(4)

264 C(7C)-C(8C)-C(19C) 119.5(4) C(5D)-C(4D)-C(3D) 120.1(4)

C(10C)-C(9C)-C(8C) 121.2(4) C(4D)-C(5D)-C(6D) 120.2(4)

C(9C)-C(10C)-C(11C) 119.7(4) C(5D)-C(6D)-C(1D) 120.4(4)

C(10C)-C(11C)-C(12C) 120.1(4) C(5D)-C(6D)-C(7D) 120.4(3)

C(11C)-C(12C)-C(7C) 120.7(5) C(1D)-C(6D)-C(7D) 119.1(3)

C(18C)-C(13C)-C(14C) 119.5(4) C(12D)-C(7D)-C(8D) 119.4(4)

C(18C)-C(13C)-C(2C) 121.6(4) C(12D)-C(7D)-C(6D) 121.8(4)

C(14C)-C(13C)-C(2C) 118.8(4) C(8D)-C(7D)-C(6D) 118.8(4)

C(15C)-C(14C)-C(13C) 119.2(5) C(9D)-C(8D)-C(7D) 119.6(4)

C(15C)-C(14C)-C(20C) 122.3(4) C(9D)-C(8D)-C(19D) 122.0(4)

C(13C)-C(14C)-C(20C) 118.5(4) C(7D)-C(8D)-C(19D) 118.3(4)

C(16C)-C(15C)-C(14C) 120.6(5) C(8D)-C(9D)-C(10D) 120.1(4)

C(17C)-C(16C)-C(15C) 120.4(4) C(11D)-C(10D)-C(9D) 120.3(4)

C(16C)-C(17C)-C(18C) 120.2(5) C(10D)-C(11D)-C(12D) 120.5(4)

C(13C)-C(18C)-C(17C) 120.1(5) C(11D)-C(12D)-C(7D) 120.1(4)

C(8C)-C(19C)-N(1C) 114.0(3) C(14D)-C(13D)-C(18D) 119.4(4)

C(14C)-C(20C)-N(2C) 112.0(3) C(14D)-C(13D)-C(2D) 118.0(4)

C(2D)-C(1D)-C(6D) 119.0(3) C(18D)-C(13D)-C(2D) 122.5(4)

C(2D)-C(1D)-Pd(1D) 125.8(3) C(15D)-C(14D)-C(13D) 119.6(4)

C(6D)-C(1D)-Pd(1D) 115.2(3) C(15D)-C(14D)-C(20D) 120.6(4)

C(1D)-C(2D)-C(3D) 120.0(3) C(13D)-C(14D)-C(20D) 119.7(3)

C(1D)-C(2D)-C(13D) 120.7(3) C(16D)-C(15D)-C(14D) 120.0(4)

C(3D)-C(2D)-C(13D) 118.8(3) C(17D)-C(16D)-C(15D) 120.8(4)

C(4D)-C(3D)-C(2D) 120.2(4) C(16D)-C(17D)-C(18D) 119.7(4)

265 C(17D)-C(18D)-C(13D) 120.4(4) C(14D)-C(20D)-N(2D) 112.9(3)

C(8D)-C(19D)-N(1D) 111.9(3)

266 A13. Crystallographic Data for Compound 5.11.

Figure A12. An ORTEP drawing (30% probability thermal ellipsoids) of 5.11 with atom labeling scheme.

Table A21. Crystal Data and Structure Refinement for 5.11.

Complex 4·(THF)2

Empirical formula C81H97I3N6O5Pd3

Formula weight 1934.55

Temperature (K) 100

267 Wavelength (Å) 0.71073

Crystal system Triclinic

Space group P-1

Unit cell dimensions a = 15.0361(3) α = 74.418(1)

b = 16.0807(3) β = 74.891(1)

c = 17.5379(3) γ = 76.753(1)

Vo l u me ( Å 3) 3885.3(1)

Z 2

Density (calcd. g/cm3) 1.654

Absorption coeff. (mm-1) 1.933

F(000) 1924

Crystal size (mm) 0.05×0.08×0.13

Crystal color & shape Pale orange block

θ range data collection 1.23-28.31

Limiting indices -20< h <20 -21< k <21 -23< l <23

Reflections collected 77176

Independent reflections 19215 (Rint = 0.0825)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 19215/0/881

Goodness-of-fit on F2 1.038

Final R indices [I>2σ(I)]a,b R1 = 0.0614 wR2 = 0.1515

R indices (all data) R1 = 0.1016 wR2 = 0.1765

268 Table A24. Bond lengths (Å) and angles (°) for 5.11.

Pd(1C)-C(1C) 1.991(6) C(17)-C(16) 1.374(12)

Pd(1C)-O(1C) 2.117(4) C(14)-C(15) 1.393(10)

Pd(1C)-N(1C) 2.118(5) C(14)-C(13) 1.409(10)

Pd(1C)-N(2C) 2.146(5) C(14)-C(20) 1.504(9)

Pd(1B)-C(1B) 1.987(6) C(15)-C(16) 1.391(11)

Pd(1B)-O(1B) 2.119(4) C(13)-C(2) 1.494(10)

Pd(1B)-N(1B) 2.127(5) C(2)-C(3) 1.420(9)

Pd(1B)-N(2B) 2.132(5) C(12)-C(11) 1.386(11)

Pd(1)-C(1) 1.987(6) C(12)-C(7) 1.417(10)

Pd(1)-O(1A) 2.111(4) C(7)-C(6) 1.509(10)

Pd(1)-N(2) 2.130(6) C(11)-C(10) 1.388(12)

Pd(1)-N(1) 2.135(6) C(20)-N(2) 1.498(8)

C(1)-C(2) 1.389(10) C(9)-C(10) 1.399(11)

C(1)-C(6) 1.406(10) C(21)-N(1) 1.488(9)

C(19)-N(1) 1.499(9) C(23)-N(2) 1.484(9)

C(19)-C(8) 1.512(10) C(24)-N(2) 1.487(8)

C(8)-C(7) 1.396(10) C(22)-N(1) 1.497(9)

C(8)-C(9) 1.403(10) C(7B)-C(12B) 1.394(9)

C(4)-C(3) 1.379(11) C(7B)-C(8B) 1.402(9)

C(4)-C(5) 1.380(11) C(7B)-C(6B) 1.480(8)

C(5)-C(6) 1.396(9) C(1B)-C(2B) 1.400(9)

C(18)-C(17) 1.369(11) C(1B)-C(6B) 1.415(8)

C(18)-C(13) 1.382(10) C(14B)-C(15B) 1.397(9)

269 C(14B)-C(13B) 1.403(9) C(8C)-C(7C) 1.405(10)

C(14B)-C(20B) 1.483(9) C(8C)-C(9C) 1.406(10)

C(4B)-C(5B) 1.384(9) C(8C)-C(19C) 1.498(9)

C(4B)-C(3B) 1.385(9) C(4C)-C(5C) 1.376(10)

C(20B)-N(2B) 1.502(8) C(4C)-C(3C) 1.392(10)

C(11B)-C(10B) 1.371(10) C(3C)-C(2C) 1.396(9)

C(11B)-C(12B) 1.396(10) C(7C)-C(12C) 1.409(9)

C(18B)-C(13B) 1.387(9) C(7C)-C(6C) 1.464(9)

C(18B)-C(17B) 1.396(9) C(6C)-C(5C) 1.416(9)

C(13B)-C(2B) 1.498(8) C(12C)-C(11C) 1.399(11)

C(9B)-C(10B) 1.387(10) C(2C)-C(13C) 1.483(9)

C(9B)-C(8B) 1.388(9) C(9C)-C(10C) 1.382(10)

C(6B)-C(5B) 1.394(8) C(10C)-C(11C) 1.385(12)

C(15B)-C(16B) 1.379(10) C(14C)-C(15C) 1.386(9)

C(2B)-C(3B) 1.394(9) C(14C)-C(13C) 1.417(9)

C(16B)-C(17B) 1.382(11) C(14C)-C(20C) 1.500(9)

C(19B)-C(8B) 1.497(9) C(13C)-C(18C) 1.391(9)

C(19B)-N(1B) 1.503(8) C(18C)-C(17C) 1.389(11)

C(24B)-N(2B) 1.499(8) C(15C)-C(16C) 1.393(11)

C(21B)-N(1B) 1.493(8) C(16C)-C(17C) 1.398(12)

C(23B)-N(2B) 1.479(8) C(19C)-N(1C) 1.496(8)

C(22B)-N(1B) 1.471(9) C(20C)-N(2C) 1.488(8)

C(1C)-C(6C) 1.402(9) C(23C)-N(2C) 1.489(8)

C(1C)-C(2C) 1.403(9) C(24C)-N(2C) 1.489(8)

270 C(22C)-N(1C) 1.498(8) O(1C)-Pd(1C)-N(1C) 87.33(18)

C(21C)-N(1C) 1.492(8) C(1C)-Pd(1C)-N(2C) 87.4(2)

I(1)-I(2) 2.9622(9) O(1C)-Pd(1C)-N(2C) 95.76(18)

I(2)-I(3) 2.9072(10) N(1C)-Pd(1C)-N(2C) 176.8(2)

O(1C)-C(111) 1.282(7) C(1B)-Pd(1B)-O(1B) 171.1(2)

O(1B)-C(111) 1.301(7) C(1B)-Pd(1B)-N(1B) 89.0(2)

O(1A)-C(111) 1.272(7) O(1B)-Pd(1B)-N(1B) 96.10(18)

C(4S)-O(1S) 1.32(2) C(1B)-Pd(1B)-N(2B) 89.3(2)

C(4S)-C(3S) 1.45(3) O(1B)-Pd(1B)-N(2B) 85.59(17)

C(2S)-C(1S) 1.52(2) N(1B)-Pd(1B)-N(2B) 178.27(19)

C(2S)-C(3S) 1.64(3) C(1)-Pd(1)-O(1A) 174.5(2)

C(1S)-O(1S) 1.35(3) C(1)-Pd(1)-N(2) 88.4(2)

O(2S)-C(8S) 1.45(3) O(1A)-Pd(1)-N(2) 95.3(2)

O(2S)-C(5S) 1.79(3) C(1)-Pd(1)-N(1) 90.0(2)

C(7SS)-C(6SS) 1.53(4) O(1A)-Pd(1)-N(1) 86.17(19)

C(7SS)-C(8SS) 1.81(4) N(2)-Pd(1)-N(1) 178.0(2)

C(7S)-C(8S) 1.35(3) C(2)-C(1)-C(6) 118.1(6)

C(7S)-C(6S) 1.84(3) C(2)-C(1)-Pd(1) 121.9(5)

C(6SS)-C(5SS) 1.31(3) C(6)-C(1)-Pd(1) 120.0(5)

C(5SS)-O(2SS) 1.74(4) N(1)-C(19)-C(8) 112.5(5)

C(6S)-C(5S) 1.16(3) C(7)-C(8)-C(9) 118.8(7)

C(7)-C(8)-C(19) 119.3(6)

C(1C)-Pd(1C)-O(1C) 172.2(2) C(9)-C(8)-C(19) 121.8(7)

C(1C)-Pd(1C)-N(1C) 89.5(2) C(3)-C(4)-C(5) 120.3(6)

271 C(4)-C(5)-C(6) 119.8(7) C(4)-C(3)-C(2) 119.9(7)

C(17)-C(18)-C(13) 120.2(7) C(11)-C(10)-C(9) 119.4(7)

C(18)-C(17)-C(16) 122.3(7) C(12B)-C(7B)-C(8B) 118.3(6)

C(15)-C(14)-C(13) 119.8(6) C(12B)-C(7B)-C(6B) 122.1(6)

C(15)-C(14)-C(20) 121.1(6) C(8B)-C(7B)-C(6B) 119.5(6)

C(13)-C(14)-C(20) 119.1(6) C(2B)-C(1B)-C(6B) 118.5(5)

C(16)-C(15)-C(14) 120.4(7) C(2B)-C(1B)-Pd(1B) 122.7(4)

C(18)-C(13)-C(14) 118.9(7) C(6B)-C(1B)-Pd(1B) 118.7(4)

C(18)-C(13)-C(2) 123.3(7) C(15B)-C(14B)-C(13B) 118.6(6)

C(14)-C(13)-C(2) 117.8(6) C(15B)-C(14B)-C(20B) 121.3(6)

C(1)-C(2)-C(3) 120.4(7) C(13B)-C(14B)-C(20B) 120.0(5)

C(1)-C(2)-C(13) 120.2(6) C(5B)-C(4B)-C(3B) 120.2(6)

C(3)-C(2)-C(13) 119.1(6) C(14B)-C(20B)-N(2B) 113.8(5)

C(11)-C(12)-C(7) 118.9(7) C(10B)-C(11B)-C(12B) 119.4(7)

C(8)-C(7)-C(12) 120.7(7) C(13B)-C(18B)-C(17B) 120.2(6)

C(8)-C(7)-C(6) 118.5(6) C(18B)-C(13B)-C(14B) 120.1(6)

C(12)-C(7)-C(6) 120.7(6) C(18B)-C(13B)-C(2B) 121.9(6)

C(12)-C(11)-C(10) 121.4(7) C(14B)-C(13B)-C(2B) 117.8(5)

N(2)-C(20)-C(14) 112.1(5) C(10B)-C(9B)-C(8B) 120.7(7)

C(5)-C(6)-C(1) 121.2(7) C(5B)-C(6B)-C(1B) 120.4(6)

C(5)-C(6)-C(7) 117.9(6) C(5B)-C(6B)-C(7B) 119.3(5)

C(1)-C(6)-C(7) 120.8(6) C(1B)-C(6B)-C(7B) 120.1(5)

C(17)-C(16)-C(15) 118.5(8) C(16B)-C(15B)-C(14B) 121.0(6)

C(10)-C(9)-C(8) 120.8(7) C(4B)-C(5B)-C(6B) 120.1(6)

272 C(3B)-C(2B)-C(1B) 120.3(6) C(22B)-N(1B)-C(21B) 108.7(6)

C(3B)-C(2B)-C(13B) 118.9(6) C(22B)-N(1B)-C(19B) 109.4(5)

C(1B)-C(2B)-C(13B) 120.3(5) C(21B)-N(1B)-C(19B) 106.6(5)

C(4B)-C(3B)-C(2B) 120.5(6) C(22B)-N(1B)-Pd(1B) 108.2(4)

C(15B)-C(16B)-C(17B) 120.2(6) C(21B)-N(1B)-Pd(1B) 110.6(4)

C(8B)-C(19B)-N(1B) 112.9(5) C(19B)-N(1B)-Pd(1B) 113.4(4)

C(9B)-C(8B)-C(7B) 119.9(6) C(23B)-N(2B)-C(24B) 108.3(5)

C(9B)-C(8B)-C(19B) 120.9(6) C(23B)-N(2B)-C(20B) 108.5(5)

C(7B)-C(8B)-C(19B) 119.2(6) C(24B)-N(2B)-C(20B) 107.3(5)

C(11B)-C(10B)-C(9B) 120.3(6) C(23B)-N(2B)-Pd(1B) 107.0(4)

C(7B)-C(12B)-C(11B) 121.4(7) C(24B)-N(2B)-Pd(1B) 111.7(4)

C(16B)-C(17B)-C(18B) 119.8(7) C(20B)-N(2B)-Pd(1B) 113.8(4)

C(23)-N(2)-C(24) 108.4(6) C(6C)-C(1C)-C(2C) 118.9(6)

C(23)-N(2)-C(20) 106.7(5) C(6C)-C(1C)-Pd(1C) 121.7(5)

C(24)-N(2)-C(20) 108.2(5) C(2C)-C(1C)-Pd(1C) 119.4(5)

C(23)-N(2)-Pd(1) 110.8(4) C(7C)-C(8C)-C(9C) 119.2(6)

C(24)-N(2)-Pd(1) 108.3(4) C(7C)-C(8C)-C(19C) 120.5(6)

C(20)-N(2)-Pd(1) 114.2(4) C(9C)-C(8C)-C(19C) 120.3(6)

C(21)-N(1)-C(22) 108.2(6) C(5C)-C(4C)-C(3C) 119.8(6)

C(21)-N(1)-C(19) 107.9(5) C(4C)-C(3C)-C(2C) 120.0(6)

C(22)-N(1)-C(19) 107.4(5) C(8C)-C(7C)-C(12C) 119.0(6)

C(21)-N(1)-Pd(1) 112.5(4) C(8C)-C(7C)-C(6C) 119.1(6)

C(22)-N(1)-Pd(1) 107.2(4) C(12C)-C(7C)-C(6C) 121.8(6)

C(19)-N(1)-Pd(1) 113.4(4) C(1C)-C(6C)-C(5C) 119.1(6)

273 C(1C)-C(6C)-C(7C) 120.8(6) C(19C)-N(1C)-C(22C) 108.5(5)

C(5C)-C(6C)-C(7C) 119.9(6) C(21C)-N(1C)-Pd(1C) 112.6(4)

C(11C)-C(12C)-C(7C) 120.5(7) C(19C)-N(1C)-Pd(1C) 113.7(4)

C(4C)-C(5C)-C(6C) 121.0(6) C(22C)-N(1C)-Pd(1C) 106.3(4)

C(3C)-C(2C)-C(1C) 120.8(6) C(20C)-N(2C)-C(23C) 109.6(5)

C(3C)-C(2C)-C(13C) 120.7(6) C(20C)-N(2C)-C(24C) 107.5(5)

C(1C)-C(2C)-C(13C) 118.3(6) C(23C)-N(2C)-C(24C) 107.4(5)

C(10C)-C(9C)-C(8C) 121.3(7) C(20C)-N(2C)-Pd(1C) 112.7(4)

C(9C)-C(10C)-C(11C) 119.7(7) C(23C)-N(2C)-Pd(1C) 107.3(4)

C(10C)-C(11C)-C(12C) 120.2(7) C(24C)-N(2C)-Pd(1C) 112.2(4)

C(15C)-C(14C)-C(13C) 120.2(6) I(3)-I(2)-I(1) 178.28(3)

C(15C)-C(14C)-C(20C) 122.3(6) C(111)-O(1C)-Pd(1C) 132.0(4)

C(13C)-C(14C)-C(20C) 117.5(6) C(111)-O(1B)-Pd(1B) 131.4(4)

C(18C)-C(13C)-C(14C) 119.1(6) C(111)-O(1A)-Pd(1) 131.2(4)

C(18C)-C(13C)-C(2C) 123.2(6) O(1A)-C(111)-O(1C) 121.3(5)

C(14C)-C(13C)-C(2C) 117.6(5) O(1A)-C(111)-O(1B) 119.7(5)

C(17C)-C(18C)-C(13C) 120.3(6) O(1C)-C(111)-O(1B) 118.8(5)

C(14C)-C(15C)-C(16C) 120.4(7) O(1S)-C(4S)-C(3S) 99.8(16)

C(15C)-C(16C)-C(17C) 119.4(7) C(1S)-C(2S)-C(3S) 95.2(14)

C(18C)-C(17C)-C(16C) 120.6(7) O(1S)-C(1S)-C(2S) 106.4(16)

N(1C)-C(19C)-C(8C) 113.2(5) C(4S)-C(3S)-C(2S) 102.2(16)

N(2C)-C(20C)-C(14C) 111.9(5) C(8S)-O(2S)-C(5S) 100.0(16)

C(21C)-N(1C)-C(19C) 108.1(5) C(6SS)-C(7SS)-C(8SS) 109(2)

C(21C)-N(1C)-C(22C) 107.5(5) C(4S)-O(1S)-C(1S) 117.6(19)

274 C(8S)-C(7S)-C(6S) 81(2) C(5S)-C(6S)-C(7S) 114.0(17)

C(5SS)-C(6SS)-C(7SS) 108(3) C(6S)-C(5S)-O(2S) 89.7(15)

C(6SS)-C(5SS)-O(2SS) 105(2)

C(7S)-C(8S)-O(2S) 117(2)

275 A14. Crystallographic Data for Compound 5.12.

N I

Figure A13. An ORTEP drawing (30% probability thermal ellipsoids) of 5.12 with atom labeling scheme.

Table A23. Crystal Data and Structure Refinement for 5.12.

Complex 5.12

Empirical formula C24H27IN2Ni

Formula weight 529.09

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

Space group P2(1)/n

Unit cell dimensions a = 11.5371(4) α = 90.00

b = 15.6442(6) β = 101.313(2)

c = 12.0675(4) γ = 90.00

276 Vo l u me ( Å 3) 2135.7(1)

Z 4

Density (calcd. g/cm3) 1.645

Absorption coeff. (mm-1) 2.366

F(000) 1064

Crystal size (mm) 0.11×0.31×0.40

Crystal color & shape Purple block

θ range data collection 2.16-28.55

Limiting indices -15 < h < 15 -20 < k < 20 -16 < l < 16

Reflections collected 27583

Independent reflections 5373 (Rint = 0.0237)

Refinement method Full-matrix least-square on F2

Data/restraints/parameters 5373/0/257

Goodness-of-fit on F2 1.148

Final R indices [I>2σ(I)]a,b R1 = 0.0465 wR2 = 0.1181

R indices (all data) R1 = 0.0491 wR2 = 0.1199

277 Table A26. Bond lengths (Å) and angles (°) for 5.12.

I(1)-Ni(1) 2.6903(6) C(14)-C(13) 1.395(6)

Ni(1)-C(1) 1.904(4) C(14)-C(20) 1.503(6)

Ni(1)-N(2) 2.002(3) C(15)-C(16) 1.392(7)

Ni(1)-N(1) 2.030(3) C(13)-C(18) 1.394(6)

N(2)-C(23) 1.486(5) C(16)-C(17) 1.379(9)

N(2)-C(24) 1.487(5) C(19)-N(1) 1.508(5)

N(2)-C(20) 1.517(6) C(21)-N(1) 1.492(5)

C(1)-C(6) 1.404(5) C(22)-N(1) 1.496(5)

C(1)-C(2) 1.422(6) C(18)-C(17) 1.384(8)

C(2)-C(3) 1.399(6)

C(2)-C(13) 1.484(6) C(1)-Ni(1)-N(2) 91.57(15)

C(3)-C(4) 1.370(7) C(1)-Ni(1)-N(1) 88.78(15)

C(4)-C(5) 1.383(7) N(2)-Ni(1)-N(1) 164.56(14)

C(6)-C(5) 1.397(5) C(1)-Ni(1)-I(1) 151.62(13)

C(6)-C(7) 1.494(6) N(2)-Ni(1)-I(1) 91.85(10)

C(8)-C(9) 1.395(6) N(1)-Ni(1)-I(1) 95.17(10)

C(8)-C(7) 1.405(6) C(23)-N(2)-C(24) 109.5(3)

C(8)-C(19) 1.505(6) C(23)-N(2)-C(20) 104.7(3)

C(9)-C(10) 1.383(8) C(24)-N(2)-C(20) 105.5(3)

C(12)-C(7) 1.391(6) C(23)-N(2)-Ni(1) 112.2(3)

C(12)-C(11) 1.391(7) C(24)-N(2)-Ni(1) 107.5(2)

C(10)-C(11) 1.369(8) C(20)-N(2)-Ni(1) 117.0(2)

C(14)-C(15) 1.395(6) C(6)-C(1)-C(2) 117.4(4)

278 C(6)-C(1)-Ni(1) 113.7(3) C(10)-C(11)-C(12) 119.6(5)

C(2)-C(1)-Ni(1) 128.9(3) C(15)-C(14)-C(13) 119.0(4)

C(3)-C(2)-C(1) 120.2(4) C(15)-C(14)-C(20) 121.5(4)

C(3)-C(2)-C(13) 119.1(4) C(13)-C(14)-C(20) 119.1(4)

C(1)-C(2)-C(13) 120.5(4) C(16)-C(15)-C(14) 120.6(5)

C(4)-C(3)-C(2) 120.8(4) C(18)-C(13)-C(14) 119.7(4)

C(3)-C(4)-C(5) 120.2(4) C(18)-C(13)-C(2) 121.7(4)

C(5)-C(6)-C(1) 121.2(4) C(14)-C(13)-C(2) 118.4(4)

C(5)-C(6)-C(7) 118.9(4) C(17)-C(16)-C(15) 120.1(5)

C(1)-C(6)-C(7) 119.7(3) C(14)-C(20)-N(2) 114.5(3)

C(4)-C(5)-C(6) 120.1(4) C(8)-C(19)-N(1) 111.5(3)

C(9)-C(8)-C(7) 119.0(4) C(17)-C(18)-C(13) 120.8(5)

C(9)-C(8)-C(19) 122.6(4) C(16)-C(17)-C(18) 119.7(5)

C(7)-C(8)-C(19) 118.4(4) C(21)-N(1)-C(22) 105.8(3)

C(10)-C(9)-C(8) 120.5(5) C(21)-N(1)-C(19) 106.4(3)

C(7)-C(12)-C(11) 120.7(5) C(22)-N(1)-C(19) 108.8(3)

C(11)-C(10)-C(9) 120.8(5) C(21)-N(1)-Ni(1) 116.6(3)

C(12)-C(7)-C(8) 119.3(4) C(22)-N(1)-Ni(1) 106.7(2)

C(12)-C(7)-C(6) 122.5(4) C(19)-N(1)-Ni(1) 112.2(2)

C(8)-C(7)-C(6) 118.1(4)

279 A15. Crystallographic Data for Compound 6.15a.

Ph H

Pd I N

H Ph Figure A14. An ORTEP drawing (40% probability thermal ellipsoids) of 6.15a with atom labeling scheme.

Table A25. Crystal Data and Structure Refinement for 6.15a.

Complex 6.15a

Empirical formula C36H31IN2Pd

Formula weight 724.93

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Trigonal

Space group P31

280 Unit cell dimensions a = 15.7499(2) α = 90.00

b = 15.7499(2) β = 90.00

c = 10.5822(2) γ = 120.00

Vo l u me ( Å 3) 2273.33(6)

Z 3

Density (calcd g/cm3) 1.589

Absorption coeff. (mm-1) 1.658

F(000) 1080

Crystal size (mm) 0.18×0.17×0.17

Crystal color & shape colorless block

θ range data collection 2.44-27.99

Limiting indices -20< h <20 -20< k < 20 -13< l < 13

Reflections collected 51541

Independent reflections 7199 (Rint = 0.0342)

Refinement method Full-matrix least-square on F2

Data/restraint/parameters 7199/1/363

Goodness-of-fit on F2 1.019

Final R indices [I>2σ(I)]a,b R1 = 0.0139 wR2 = 0.0335

R indices (all data) R1 = 0.0143 wR2 = 0.0336

281 Table A28. Bond lengths (Å) and angles (°) for 6.15a.

Pd(1)-C(1) 1.9702(17) C(13)-C(18) 1.395(2)

Pd(1)-N(1) 2.0283(14) C(13)-C(14) 1.417(2)

Pd(1)-N(2) 2.0334(14) C(14)-C(15) 1.396(2)

Pd(1)-I(1) 2.71557(16) C(14)-C(20) 1.466(2)

N(1)-C(19) 1.283(2) C(15)-C(16) 1.383(3)

N(1)-C(21) 1.501(2) C(16)-C(17) 1.378(3)

N(2)-C(20) 1.280(2) C(17)-C(18) 1.391(3)

N(2)-C(29) 1.497(2) C(21)-C(23) 1.515(2)

C(1)-C(6) 1.396(2) C(21)-C(22) 1.533(3)

C(1)-C(2) 1.414(2) C(23)-C(28) 1.391(3)

C(2)-C(3) 1.396(3) C(23)-C(24) 1.396(3)

C(2)-C(13) 1.489(2) C(24)-C(25) 1.389(3)

C(3)-C(4) 1.382(3) C(25)-C(26) 1.380(3)

C(4)-C(5) 1.393(3) C(26)-C(27) 1.380(3)

C(5)-C(6) 1.391(2) C(27)-C(28) 1.388(3)

C(6)-C(7) 1.506(2) C(29)-C(31) 1.513(2)

C(7)-C(12) 1.396(2) C(29)-C(30) 1.535(2)

C(7)-C(8) 1.405(2) C(31)-C(32) 1.389(2)

C(8)-C(9) 1.400(2) C(31)-C(36) 1.395(2)

C(8)-C(19) 1.475(2) C(32)-C(33) 1.398(2)

C(9)-C(10) 1.382(3) C(33)-C(34) 1.389(3)

C(10)-C(11) 1.381(3) C(34)-C(35) 1.390(3)

C(11)-C(12) 1.392(2) C(35)-C(36) 1.381(3)

282 C(1)-C(6)-C(7) 121.96(15)

C(1)-Pd(1)-N(1) 87.30(6) C(12)-C(7)-C(8) 118.22(15)

C(1)-Pd(1)-N(2) 85.92(6) C(12)-C(7)-C(6) 117.90(15)

N(1)-Pd(1)-N(2) 172.98(6) C(8)-C(7)-C(6) 123.73(16)

C(1)-Pd(1)-I(1) 171.62(5) C(9)-C(8)-C(7) 119.54(16)

N(1)-Pd(1)-I(1) 96.25(4) C(9)-C(8)-C(19) 115.29(15)

N(2)-Pd(1)-I(1) 90.71(4) C(7)-C(8)-C(19) 125.04(15)

C(19)-N(1)-C(21) 119.37(15) C(10)-C(9)-C(8) 121.09(17)

C(19)-N(1)-Pd(1) 122.75(12) C(11)-C(10)-C(9) 119.72(17)

C(21)-N(1)-Pd(1) 117.88(11) C(10)-C(11)-C(12) 119.75(17)

C(20)-N(2)-C(29) 120.98(14) C(11)-C(12)-C(7) 121.52(17)

C(20)-N(2)-Pd(1) 119.45(12) C(18)-C(13)-C(14) 117.64(17)

C(29)-N(2)-Pd(1) 119.41(10) C(18)-C(13)-C(2) 118.79(16)

C(6)-C(1)-C(2) 120.02(15) C(14)-C(13)-C(2) 123.56(16)

C(6)-C(1)-Pd(1) 122.78(12) C(15)-C(14)-C(13) 119.77(16)

C(2)-C(1)-Pd(1) 117.19(12) C(15)-C(14)-C(20) 117.47(16)

C(3)-C(2)-C(1) 119.06(16) C(13)-C(14)-C(20) 122.72(16)

C(3)-C(2)-C(13) 119.65(15) C(16)-C(15)-C(14) 121.02(18)

C(1)-C(2)-C(13) 121.08(15) C(17)-C(16)-C(15) 119.62(18)

C(4)-C(3)-C(2) 120.76(16) C(16)-C(17)-C(18) 120.03(18)

C(3)-C(4)-C(5) 119.94(17) C(17)-C(18)-C(13) 121.72(18)

C(6)-C(5)-C(4) 120.58(17) N(1)-C(19)-C(8) 125.81(16)

C(5)-C(6)-C(1) 119.62(15) N(2)-C(20)-C(14) 122.60(15)

C(5)-C(6)-C(7) 118.41(16) N(1)-C(21)-C(23) 113.83(14)

283 N(1)-C(21)-C(22) 107.81(15) N(2)-C(29)-C(30) 108.70(13)

C(23)-C(21)-C(22) 114.49(16) C(31)-C(29)-C(30) 110.15(14)

C(28)-C(23)-C(24) 118.21(17) C(32)-C(31)-C(36) 118.95(16)

C(28)-C(23)-C(21) 123.52(17) C(32)-C(31)-C(29) 120.48(16)

C(24)-C(23)-C(21) 118.27(17) C(36)-C(31)-C(29) 120.51(16)

C(25)-C(24)-C(23) 120.5(2) C(31)-C(32)-C(33) 120.55(17)

C(26)-C(25)-C(24) 120.4(2) C(34)-C(33)-C(32) 119.72(17)

C(27)-C(26)-C(25) 119.70(19) C(33)-C(34)-C(35) 119.89(17)

C(26)-C(27)-C(28) 120.0(2) C(36)-C(35)-C(34) 120.12(17)

C(27)-C(28)-C(23) 121.10(19) C(35)-C(36)-C(31) 120.77(17)

N(2)-C(29)-C(31) 113.55(13)

284 A16. Crystallographic Data for Compound 6.15b.

Ph H N

N I H Ph

Figure A15. An ORTEP drawing (40% probability thermal ellipsoids) of 6.15b with atom labeling scheme. Only one of the three independent molecules in the asymmetric unit is shown.

Table A27. Crystal Data and Structure Refinement for 6.15b.

Complex 6.15b · 1/3 C6H6

Empirical formula C38H33IN2Pd

Formula weight 750.96

Temperature (K) 100

Wavelength (Å) 0.71073

Crystal system Monoclinic

285 Space group P21

Unit cell dimensions a = 10.0764(3) α = 90.00

b = 14.6621(4) β = 97.881(2)

c = 33.0584(10) γ = 90.00

Vo l u me ( Å 3) 4838.0(2)

Z 6

Density (calcd g/cm3) 1.547

Absorption coeff. (mm-1) 1.561

F(000) 2244

Crystal size (mm) 0.24×0.21×0.01

Crystal color & shape colorless thin plate

θ range data collection 1.24-30.67

Limiting indices -14< h <13 -20< k < 20 -47< l < 46

Reflections collected 92517

Independent reflections 29483 (Rint = 0.1219)

Refinement method Full-matrix least-square on F2

Data/restraint/parameters 29483/1/1111

Goodness-of-fit on F2 0.978

Final R indices [I>2σ(I)]a,b R1 = 0.0669 wR2 = 0.1141

R indices (all data) R1 = 0.1324 wR2 = 0.1385

286 Table A30. Bond lengths (Å) and angles (°) for 6.15b.

C(1)-C(2) 1.388(11) C(19)-N(1) 1.271(10)

C(1)-C(6) 1.410(11) C(20)-N(2) 1.271(10)

C(1)-Pd(1) 1.964(8) C(21)-N(1) 1.486(10)

C(2)-C(3) 1.406(11) C(21)-C(23) 1.526(11)

C(2)-C(13) 1.497(11) C(21)-C(22) 1.533(10)

C(3)-C(4) 1.374(12) C(23)-C(24) 1.394(12)

C(4)-C(5) 1.388(12) C(23)-C(28) 1.418(12)

C(5)-C(6) 1.395(11) C(24)-C(25) 1.389(13)

C(6)-C(7) 1.500(11) C(25)-C(26) 1.386(13)

C(7)-C(12) 1.391(12) C(26)-C(27) 1.376(13)

C(7)-C(8) 1.426(11) C(27)-C(28) 1.390(12)

C(8)-C(9) 1.406(11) C(29)-N(2) 1.485(10)

C(8)-C(19) 1.465(12) C(29)-C(31) 1.516(12)

C(9)-C(10) 1.380(12) C(29)-C(30) 1.527(11)

C(10)-C(11) 1.384(12) C(31)-C(36) 1.386(12)

C(11)-C(12) 1.389(12) C(31)-C(32) 1.394(12)

C(13)-C(14) 1.387(11) C(32)-C(33) 1.393(13)

C(13)-C(18) 1.389(11) C(33)-C(34) 1.352(13)

C(14)-C(15) 1.403(11) C(34)-C(35) 1.390(14)

C(14)-C(20) 1.489(11) C(35)-C(36) 1.394(14)

C(15)-C(16) 1.388(11) C(1B)-C(2B) 1.368(11)

C(16)-C(17) 1.393(12) C(1B)-C(6B) 1.406(11)

C(17)-C(18) 1.392(12) C(1B)-Pd(1B) 1.960(8)

287 C(2B)-C(3B) 1.407(11) C(21B)-C(23B) 1.518(12)

C(2B)-C(13B) 1.506(13) C(23B)-C(28B) 1.397(11)

C(3B)-C(4B) 1.384(13) C(23B)-C(24B) 1.403(12)

C(4B)-C(5B) 1.397(13) C(24B)-C(25B) 1.393(12)

C(5B)-C(6B) 1.415(12) C(25B)-C(26B) 1.381(12)

C(6B)-C(7B) 1.495(12) C(26B)-C(27B) 1.377(14)

C(7B)-C(12B) 1.383(12) C(27B)-C(28B) 1.382(14)

C(7B)-C(8B) 1.401(11) C(29B)-N(1B) 1.511(10)

C(8B)-C(9B) 1.381(12) C(29B)-C(30B) 1.512(12)

C(8B)-C(19B) 1.495(12) C(29B)-C(31B) 1.513(11)

C(9B)-C(10B) 1.403(13) C(31B)-C(36B) 1.380(12)

C(10B)-C(11B) 1.382(12) C(31B)-C(32B) 1.404(12)

C(11B)-C(12B) 1.383(12) C(32B)-C(33B) 1.394(12)

C(13B)-C(14B) 1.415(12) C(33B)-C(34B) 1.358(14)

C(13B)-C(18B) 1.416(12) C(34B)-C(35B) 1.420(14)

C(14B)-C(15B) 1.401(12) C(35B)-C(36B) 1.375(13)

C(14B)-C(20B) 1.484(11) C(1C)-C(2C) 1.380(11)

C(15B)-C(16B) 1.400(13) C(1C)-C(6C) 1.411(12)

C(16B)-C(17B) 1.365(14) C(1C)-Pd(1C) 1.969(8)

C(17B)-C(18B) 1.380(14) C(2C)-C(3C) 1.409(12)

C(19B)-N(1B) 1.278(10) C(2C)-C(13C) 1.492(12)

C(20B)-N(2B) 1.272(10) C(3C)-C(4C) 1.395(13)

C(21B)-N(2B) 1.486(10) C(4C)-C(5C) 1.376(12)

C(21B)-C(22B) 1.502(12) C(5C)-C(6C) 1.413(12)

288 C(6C)-C(7C) 1.480(12) C(26C)-C(27C) 1.379(16)

C(7C)-C(8C) 1.399(11) C(27C)-C(28C) 1.393(13)

C(7C)-C(12C) 1.414(12) C(29C)-N(2C) 1.489(9)

C(8C)-C(9C) 1.399(11) C(29C)-C(30C) 1.513(10)

C(8C)-C(19C) 1.478(11) C(29C)-C(31C) 1.532(12)

C(9C)-C(10C) 1.376(12) C(31C)-C(32C) 1.375(12)

C(10C)-C(11C) 1.372(12) C(31C)-C(36C) 1.380(11)

C(11C)-C(12C) 1.376(13) C(32C)-C(33C) 1.416(14)

C(13C)-C(14C) 1.396(11) C(33C)-C(34C) 1.358(13)

C(13C)-C(18C) 1.418(11) C(34C)-C(35C) 1.378(13)

C(14C)-C(15C) 1.420(11) C(35C)-C(36C) 1.379(13)

C(14C)-C(20C) 1.490(11) C(1S)-C(2S) 1.370(18)

C(15C)-C(16C) 1.365(12) C(1S)-C(6S) 1.387(17)

C(16C)-C(17C) 1.395(13) C(2S)-C(3S) 1.352(17)

C(17C)-C(18C) 1.374(13) C(3S)-C(4S) 1.379(18)

C(19C)-N(1C) 1.269(10) C(4S)-C(5S) 1.385(17)

C(20C)-N(2C) 1.278(10) C(5S)-C(6S) 1.353(16)

C(21C)-N(1C) 1.497(10) I(1)-Pd(1) 2.7058(8)

C(21C)-C(22C) 1.511(11) I(1B)-Pd(1B) 2.7288(8)

C(21C)-C(23C) 1.554(12) I(1C)-Pd(1C) 2.7309(8)

C(23C)-C(24C) 1.367(13) N(1)-Pd(1) 2.026(6)

C(23C)-C(28C) 1.409(12) N(2)-Pd(1) 2.029(7)

C(24C)-C(25C) 1.402(13) N(1B)-Pd(1B) 2.040(6)

C(25C)-C(26C) 1.368(16) N(2B)-Pd(1B) 2.030(7)

289 N(1C)-Pd(1C) 2.018(6) C(11)-C(12)-C(7) 121.4(8)

N(2C)-Pd(1C) 2.030(7) C(14)-C(13)-C(18) 117.9(8)

C(14)-C(13)-C(2) 125.8(7)

C(2)-C(1)-C(6) 120.1(7) C(18)-C(13)-C(2) 116.2(7)

C(2)-C(1)-Pd(1) 121.2(6) C(13)-C(14)-C(15) 121.4(8)

C(6)-C(1)-Pd(1) 118.7(6) C(13)-C(14)-C(20) 124.1(8)

C(1)-C(2)-C(3) 119.9(7) C(15)-C(14)-C(20) 114.4(7)

C(1)-C(2)-C(13) 121.4(7) C(16)-C(15)-C(14) 119.5(8)

C(3)-C(2)-C(13) 118.7(7) C(15)-C(16)-C(17) 119.8(8)

C(4)-C(3)-C(2) 119.7(8) C(18)-C(17)-C(16) 119.5(8)

C(3)-C(4)-C(5) 120.9(8) C(13)-C(18)-C(17) 121.8(8)

C(4)-C(5)-C(6) 120.2(8) N(1)-C(19)-C(8) 124.9(8)

C(5)-C(6)-C(1) 119.1(7) N(2)-C(20)-C(14) 124.7(7)

C(5)-C(6)-C(7) 117.8(7) N(1)-C(21)-C(23) 109.2(6)

C(1)-C(6)-C(7) 122.9(7) N(1)-C(21)-C(22) 114.4(7)

C(12)-C(7)-C(8) 118.9(7) C(23)-C(21)-C(22) 110.5(7)

C(12)-C(7)-C(6) 118.2(8) C(24)-C(23)-C(28) 118.4(8)

C(8)-C(7)-C(6) 122.8(8) C(24)-C(23)-C(21) 122.2(8)

C(9)-C(8)-C(7) 119.0(8) C(28)-C(23)-C(21) 119.4(8)

C(9)-C(8)-C(19) 116.3(7) C(25)-C(24)-C(23) 121.0(9)

C(7)-C(8)-C(19) 124.8(7) C(26)-C(25)-C(24) 119.5(10)

C(10)-C(9)-C(8) 119.9(8) C(27)-C(26)-C(25) 120.9(9)

C(9)-C(10)-C(11) 121.6(8) C(26)-C(27)-C(28) 120.1(9)

C(10)-C(11)-C(12) 119.0(9) C(27)-C(28)-C(23) 120.1(8)

290 N(2)-C(29)-C(31) 109.6(7) C(12B)-C(7B)-C(6B) 118.3(7)

N(2)-C(29)-C(30) 113.8(7) C(8B)-C(7B)-C(6B) 125.1(8)

C(31)-C(29)-C(30) 112.2(7) C(9B)-C(8B)-C(7B) 120.8(8)

C(36)-C(31)-C(32) 117.8(9) C(9B)-C(8B)-C(19B) 116.2(7)

C(36)-C(31)-C(29) 119.3(8) C(7B)-C(8B)-C(19B) 122.8(7)

C(32)-C(31)-C(29) 122.9(8) C(8B)-C(9B)-C(10B) 120.6(8)

C(33)-C(32)-C(31) 121.3(9) C(11B)-C(10B)-C(9B) 119.4(9)

C(34)-C(33)-C(32) 120.0(10) C(10B)-C(11B)-C(12B) 118.3(9)

C(33)-C(34)-C(35) 120.1(10) C(11B)-C(12B)-C(7B) 124.1(8)

C(34)-C(35)-C(36) 120.0(9) C(14B)-C(13B)-C(18B) 118.5(8)

C(31)-C(36)-C(35) 120.5(9) C(14B)-C(13B)-C(2B) 122.5(8)

C(2B)-C(1B)-C(6B) 119.8(8) C(18B)-C(13B)-C(2B) 118.8(8)

C(2B)-C(1B)-Pd(1B) 121.4(6) C(15B)-C(14B)-C(13B) 118.9(8)

C(6B)-C(1B)-Pd(1B) 118.6(6) C(15B)-C(14B)-C(20B) 116.6(8)

C(1B)-C(2B)-C(3B) 119.7(9) C(13B)-C(14B)-C(20B) 124.4(8)

C(1B)-C(2B)-C(13B) 122.3(7) C(16B)-C(15B)-C(14B) 121.1(9)

C(3B)-C(2B)-C(13B) 117.9(8) C(17B)-C(16B)-C(15B) 119.7(9)

C(4B)-C(3B)-C(2B) 121.5(9) C(16B)-C(17B)-C(18B) 120.9(9)

C(3B)-C(4B)-C(5B) 119.2(8) C(17B)-C(18B)-C(13B) 120.9(9)

C(4B)-C(5B)-C(6B) 119.3(9) N(1B)-C(19B)-C(8B) 123.3(7)

C(1B)-C(6B)-C(5B) 120.3(8) N(2B)-C(20B)-C(14B) 124.1(8)

C(1B)-C(6B)-C(7B) 120.9(7) N(2B)-C(21B)-C(22B) 114.8(7)

C(5B)-C(6B)-C(7B) 118.9(8) N(2B)-C(21B)-C(23B) 108.6(7)

C(12B)-C(7B)-C(8B) 116.5(8) C(22B)-C(21B)-C(23B) 113.4(7)

291 C(28B)-C(23B)-C(24B) 117.6(8) C(3C)-C(2C)-C(13C) 117.9(8)

C(28B)-C(23B)-C(21B) 123.3(8) C(4C)-C(3C)-C(2C) 119.6(8)

C(24B)-C(23B)-C(21B) 119.0(7) C(5C)-C(4C)-C(3C) 120.9(8)

C(25B)-C(24B)-C(23B) 120.5(8) C(4C)-C(5C)-C(6C) 120.1(8)

C(26B)-C(25B)-C(24B) 120.5(9) C(1C)-C(6C)-C(5C) 118.9(7)

C(27B)-C(26B)-C(25B) 119.5(9) C(1C)-C(6C)-C(7C) 121.6(8)

C(26B)-C(27B)-C(28B) 120.4(9) C(5C)-C(6C)-C(7C) 119.5(8)

C(27B)-C(28B)-C(23B) 121.4(9) C(8C)-C(7C)-C(12C) 115.7(8)

N(1B)-C(29B)-C(30B) 111.7(7) C(8C)-C(7C)-C(6C) 126.0(7)

N(1B)-C(29B)-C(31B) 114.0(6) C(12C)-C(7C)-C(6C) 118.3(8)

C(30B)-C(29B)-C(31B) 112.5(7) C(9C)-C(8C)-C(7C) 120.3(7)

C(36B)-C(31B)-C(32B) 117.5(8) C(9C)-C(8C)-C(19C) 116.6(7)

C(36B)-C(31B)-C(29B) 122.1(7) C(7C)-C(8C)-C(19C) 123.1(7)

C(32B)-C(31B)-C(29B) 120.4(7) C(10C)-C(9C)-C(8C) 121.5(8)

C(33B)-C(32B)-C(31B) 120.3(9) C(11C)-C(10C)-C(9C) 119.7(8)

C(34B)-C(33B)-C(32B) 120.8(9) C(10C)-C(11C)-C(12C) 118.9(8)

C(33B)-C(34B)-C(35B) 119.9(9) C(11C)-C(12C)-C(7C) 123.7(9)

C(36B)-C(35B)-C(34B) 118.1(9) C(14C)-C(13C)-C(18C) 117.1(8)

C(35B)-C(36B)-C(31B) 123.1(9) C(14C)-C(13C)-C(2C) 124.9(7)

C(2C)-C(1C)-C(6C) 120.6(8) C(18C)-C(13C)-C(2C) 118.0(8)

C(2C)-C(1C)-Pd(1C) 119.9(6) C(13C)-C(14C)-C(15C) 120.6(8)

C(6C)-C(1C)-Pd(1C) 119.5(5) C(13C)-C(14C)-C(20C) 123.9(8)

C(1C)-C(2C)-C(3C) 119.9(8) C(15C)-C(14C)-C(20C) 115.3(7)

C(1C)-C(2C)-C(13C) 122.2(8) C(16C)-C(15C)-C(14C) 120.4(9)

292 C(15C)-C(16C)-C(17C) 119.5(9) C(33C)-C(34C)-C(35C) 121.3(9)

C(18C)-C(17C)-C(16C) 120.6(8) C(34C)-C(35C)-C(36C) 119.4(9)

C(17C)-C(18C)-C(13C) 121.5(9) C(35C)-C(36C)-C(31C) 120.7(8)

N(1C)-C(19C)-C(8C) 123.5(7) C(2S)-C(1S)-C(6S) 120.6(14)

N(2C)-C(20C)-C(14C) 122.5(7) C(3S)-C(2S)-C(1S) 120.4(14)

N(1C)-C(21C)-C(22C) 114.8(7) C(2S)-C(3S)-C(4S) 119.5(15)

N(1C)-C(21C)-C(23C) 109.2(7) C(3S)-C(4S)-C(5S) 119.8(14)

C(22C)-C(21C)-C(23C) 111.2(6) C(6S)-C(5S)-C(4S) 120.6(12)

C(24C)-C(23C)-C(28C) 119.8(8) C(5S)-C(6S)-C(1S) 118.8(13)

C(24C)-C(23C)-C(21C) 123.4(8) C(19)-N(1)-C(21) 122.7(7)

C(28C)-C(23C)-C(21C) 116.6(8) C(19)-N(1)-Pd(1) 121.3(6)

C(23C)-C(24C)-C(25C) 120.2(10) C(21)-N(1)-Pd(1) 115.8(5)

C(26C)-C(25C)-C(24C) 120.4(11) C(20)-N(2)-C(29) 120.5(7)

C(25C)-C(26C)-C(27C) 119.9(10) C(20)-N(2)-Pd(1) 122.3(6)

C(26C)-C(27C)-C(28C) 120.6(10) C(29)-N(2)-Pd(1) 117.2(5)

C(27C)-C(28C)-C(23C) 119.0(10) C(19B)-N(1B)-C(29B) 119.6(7)

N(2C)-C(29C)-C(30C) 114.4(7) C(19B)-N(1B)-Pd(1B) 119.7(6)

N(2C)-C(29C)-C(31C) 109.7(6) C(29B)-N(1B)-Pd(1B) 120.5(5)

C(30C)-C(29C)-C(31C) 110.6(7) C(20B)-N(2B)-C(21B) 118.5(7)

C(32C)-C(31C)-C(36C) 119.6(8) C(20B)-N(2B)-Pd(1B) 122.9(6)

C(32C)-C(31C)-C(29C) 121.7(8) C(21B)-N(2B)-Pd(1B) 118.5(5)

C(36C)-C(31C)-C(29C) 118.6(7) C(19C)-N(1C)-C(21C) 121.4(7)

C(31C)-C(32C)-C(33C) 119.8(9) C(19C)-N(1C)-Pd(1C) 122.8(6)

C(34C)-C(33C)-C(32C) 119.1(9) C(21C)-N(1C)-Pd(1C) 115.7(5)

293 C(20C)-N(2C)-C(29C) 120.6(7) N(2B)-Pd(1B)-N(1B) 171.6(3)

C(20C)-N(2C)-Pd(1C) 122.0(5) C(1B)-Pd(1B)-I(1B) 175.2(2)

C(29C)-N(2C)-Pd(1C) 117.3(5) N(2B)-Pd(1B)-I(1B) 93.38(19)

C(1)-Pd(1)-N(1) 87.3(3) N(1B)-Pd(1B)-I(1B) 95.05(18)

C(1)-Pd(1)-N(2) 88.1(3) C(1C)-Pd(1C)-N(1C) 86.6(3)

N(1)-Pd(1)-N(2) 174.7(3) C(1C)-Pd(1C)-N(2C) 87.3(3)

C(1)-Pd(1)-I(1) 175.5(2) N(1C)-Pd(1C)-N(2C) 173.6(3)

N(1)-Pd(1)-I(1) 91.74(18) C(1C)-Pd(1C)-I(1C) 178.4(2)

N(2)-Pd(1)-I(1) 93.1(2) N(1C)-Pd(1C)-I(1C) 92.13(18)

C(1B)-Pd(1B)-N(2B) 86.2(3) N(2C)-Pd(1C)-I(1C) 94.07(18)

C(1B)-Pd(1B)-N(1B) 85.4(3)

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