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AMY JEANNETTE HESTON

LEWIS AND BRÖNSTED ACID ADDUCTS OF

HEXACHLOROCYCLOTRIPHOSPHAZENE AND CARBOXYLATE DERIVATIVES

OF DISILANES

A Dissertation

Presented To

The Graduate Faculty of The University of Akron

In Partial Fulfillment

of the Requirement for the Degree

Doctor of Philosophy

Amy Jeannette Heston

August, 2005 ABSTRACT

This dissertation has two separate entities. First, in order to develop an

understanding of the irreproducibility issues involved in the conversion of the trimer

[PCl2N]3, to the polymer [PCl2N]n, the acid-base chemistry (both Lewis and Brönsted) of

15 15 [PCl2 N]3 has been investigated. The Lewis acid adducts [PCl2 N]3•AlBr3,

15 15 [PCl2 N]3•AlCl3, and [PCl2 N]3•GaCl3 have been synthesized and their reactions will be described. Reactions involving other Lewis acids will also be presented. Multinuclear and multidimensional NMR spectroscopy and X-ray crystallography proved to be critical in the characterization of the adducts. The sensitivity of the trimer to water and air inhibits adduct formation and can lead to Brönsted acid-base chemistry instead. This observation may be a first step toward understanding the irreproducibility issues mentioned above. There is also a section devoted to the ring opening polymerization of

[PCl2N]3. Several catalysts were studied to improve this process for industrial production

of [PCl2N]n in the future.

The last chapter involves the syntheses and characterization of carboxylate derivatives of disilanes. X-ray crystallography and multinuclear and multidimensional

NMR spectroscopy verified the structure from the reaction of anthracene-9-carboxylic acid and Si2(CH3)4Cl2 to form the bis-substituted disilane, Si2(CH3)4(C15H9O2)2. The bond angles and bond lengths will be described and compared to other complexes containing germanium and tin as reported in the literature.

iii

To my beloved husband,

Brian Keith Heston.

As our hearts became one: you are my friend, my love, my life.

iv ACKNOWLEDGEMENTS

I would like to thank my savior Jesus Christ for guiding me throughout the last four years and giving me each day as the opportunity to work toward my doctoral degree.

He showed me the way and I gratefully accept the plan He has set for me in my life.

I am thankful for the guidance given to me by my advisor, Dr. Claire Tessier. Her

inspiring ideas, love for teaching, and willingness to help others are just a few of her

traits that provided direction through my graduate career. I also thank her for giving me the opportunity to present my work at local and national meetings. She was a great travel

companion and always made the trips fun and exciting. Her gentle ways provided

comfort when I was nervous and I will always remember he supportive expression, “Go

for it!”, that she always told me as I presented my first poster, gave my first oral

presentation, and taught my first lecture. These thoughts will always be cherished.

I would also like to acknowledge my co-advisor Dr. Wiley Youngs for his guidance in

my project and interest in my success. I am very appreciative of all the dinners and

entertainment he provided at various meetings I attended. I am truly blessed to have Dr.

Tessier, Dr. Youngs, and Jessica Youngs in my life, as they have always made me part of

their family.

I am thankful for all the members of my committee and faculty at The University

of Akron. I am grateful for Dr. Peter Rinaldi for his collaborations in NMR

spectroscopy, providing new and exciting ideas for my project, and his interest in the

v success of the project. I thank Dr. Chrys Wesdemiotis for his kind nature, assistance in the mass spectroscopy for my project, and allowing me to present my interest in forensic science through my graduate seminar. I am also grateful to have Dr. William Brittain as a committee member and appreciate his generous gift of starting materials to support

further research in my project. I thank Dr. David Perry for his letters of recommendation and giving me the opportunity to participate in outreach programs at local schools. I

thank Dr. William Donovan for his help as I taught my first lecture course and his

humorous teaching experiences.

I would like to thank my family for their support during my graduate career.

First, and foremost, I would like to express my heartfelt love and appreciation to my husband, Brian, to which this dissertation is dedicated. His love and encouragement helped me through the various experiences, especially when I was unsure of myself. I thank my loving Grandma Schlafly, who will have the best seat for the graduation, from above. I am thankful for my Grandma Faniola, and Grandpa Ray who always let me know how proud they were that I am the first member of the family to receive a doctoral

degree. I appreciate my Mom who accompanied me on two ACS meetings, always

provided a loving ear for chemistry, and was my biggest fan in the audience. I thank my

Dad and Jackie for their support for my travels and warm thoughts for my success. I am

grateful for my brother, Tom, for listening when I was worried, providing a loving

attitude, and reminding me that what I was doing was truly an accomplishment. I thank

my sister, Lynn, for her company on trips to Akron, always finding creative stress

relievers, and allowing me to give to the community through outreach programs at her

vi library. I appreciate all the love and support from my Aunt Judy, Joyce and Keith

Heston, Grandma Dillon, as well as everyone in the Smith, Peters, and Heston families.

I would like to acknowledge the advice given by members of the Tessier-Youngs research group and love from of all of my friends in the chemistry department. I thank

everyone who participated in study groups, helped in our lab on weekends, and joined

together to form a wonderful international group of friends. I am also thankful for those

who graduated before me, Dr. Judy McCune and Dr. Lee Sanow, for their personal

interest in my wellbeing throughout the years. Collaborations with my friends, Matthew

Panzner and Debasish Banerjee, were greatly appreciated. I am happy that I was able to

share the graduate school experience with my special friends, Bart and Jouliana. All of

my friends at church and my Christian small group were always encouraging me and

interested in my progress throughout my graduate career. To all of you, I say thank you.

vii TABLE OF CONTENTS

Page

LIST OF TABLES ………………………………………………………………………xii

LIST OF FIGURES……………………………………………………………………..xiii

CHAPTER

I. AN INTRODUCTION TO PHOSPHAZENES...... 1

Introduction...... 1

Polymerization...... 4

Bonding...... 9

Structure...... 13

Bond lengths...... 13

Bond angles...... 13

Phosphazenes as Bases...... 15

Coordination Chemistry of [PCl2N]3 and Other Halogen Containing Phosphazenes...... 15

Coordination of Other Phosphazenes...... 19

References and Notes...... 28

II. EXPERIMENTAL SECTION...... 30

General Procedures...... 30

Materials and Routine Spectroscopy...... 31

X-ray crystallography...... 33

viii 15 Preparation of [PCl2 N]3...... 34

15 Syntheses of [PCl2 N]3●MX3 (M = Al, X = Cl or Br; M = Ga, X = Cl) adducts...... 35

Purification of AlBr3...... 35

15 Preparation of [PCl2 N]3•AlBr3...... 35

15 Preparation of [PCl2 N]3•AlBr3 in CH2Cl2...... 36

15 Further characterization of [PCl2 N]3•AlBr3...... 36

Purification of GaCl3...... 37

15 Preparation of [PCl2 N]3•GaCl3...... 37

15 Further characterization of [PCl2 N]3•GaCl3...... 38

Purification of AlCl3...... 38

15 Preparation of [PCl2 N]3•AlCl3...... 38

15 Further characterization of [PCl2 N]3•AlCl3...... 39

15 Preparation of [PCl2 N]3•AlCl3 in CH2Cl2...... 39

Attempted syntheses of other adducts...... 40

Purification of InCl3...... 40

Attempted syntheses of other adducts...... 40

Syntheses of Protonated Species...... 42

15 + - Preparation of H[PCl2 N]3 SbCl6 ...... 42

+ - Preparation of H[PCl2N]3 AlBr4 ...... 42

15 + - Alternative Preparation of H[PCl2 N]3 AlBr4 ...... 43

15 + - Further characterization of H[PCl2 N]3 AlBr4 ...... 44

15 + - Preparation of H[PCl2 N]3 F3CSO3 ...... 44

ix Attempts to Isolate Protonated Impurities in [PCl2N]3...... 45

Characterization of (t-Bu)N-P(N(CH2)4)3, the P1-Phosphazene Base...... 45

+ - Preparation of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ]...... 45

+ - Preparation of [(t-Bu)NH-P(N(CH2)4)3 ]Cl ...... 46

+ - Another preparation of [(t-Bu)NH-P(N(CH2)4)3 ]Cl ...... 46

+ - Isolation of (CH3CH2)3NH Cl During the Late Stages of the Synthesis of [PCl2N]3...... 46

Synthesis of Poly(dichlorophosphazene), [PCl2N]n...... 48

Melt Polymerization of [PCl2N]3...... 48

References and Notes...... 49

III. RESULTS AND DISCUSSION...... 50

Synthesis and Characterization of Lewis and Brönsted Acid 15 Adducts of [PCl2 N]3...... 50

15 N Labeled [PCl2N]3...... 50

Synthesis and characterization of Lewis Acid adducts of [PCl2N]3...... 53

Synthesis and Characterization of Brönsted Acid Adducts of [PCl2N]3...... 74

Attempts to Isolate Protonated Impurities in [PCl2N]3...... 92

Synthesis and Characterization of Poly(dichlorophosphazene), [PCl2N]n...... 95

References and Notes...... 102

IV. CARBOXYLATE DERIVATIVES OF DISILANES...... 103

Introduction...... 103

Experimental Section...... 105

General Procedures...... 105

Materials and Routine Spectroscopy...... 106

x X-ray crystallography...... 106

Preparation of Si2(CH3)4(C15H9O2)2...... 107

Other Attempts to Prepare Carboxylate Derivatives of Disilanes...... 108

Results and Discussion...... 109

Synthesis...... 109

NMR Spectroscopy...... 113

X-ray Crystallography...... 113

References and Notes...... 117

APPENDIX. SUPPLEMENTARY MATERIALS FOR ALL X-RAY CRYSTAL STRUCTURES...... 118

xi LIST OF TABLES

Table Page

1.1 Applications of some polyphosphazenes...... 3

15 15 3.1 Bond lengths and bond angles for [PCl2 N]3•AlCl3, [PCl2 N]3•AlBr3, 15 15 [PCl2 N]3•GaCl3, and [PCl2 N]3...... 58

3.2 The results of various catalysts in the ROP of [PCl2N]3...... 96

4.1 Bond angles for Compound 3...... 115

4.2 Comparison of bond angles for disilanes...... 116

xii LIST OF FIGURES

Figure Page

1.1 The structure of [PCl2N]n...... 2

1.2 Cis-trans conformation of polyphosphazenes...... 4

o 1.3 The depolymerization of [PCl2N]n above 350 C...... 7

1.4 Non-halogen containing trimeric phosphazenes that can be polymerized...... 8

1.5 The phosphonium mechanism for the ROP of [PCl2N]3...... 9

1.6 The protonation mechanism for the ROP of [PCl2N]3...... 9

1.7 The two major bonding descriptions in one repeat unit of the polyphosphazene chain...... 10

1.8 Mismatch of orbitals in the skeletal bonds of trimeric cyclic phosphazenes...... 11

1.9 The “island” model of π-bonding of [PCl2N]3...... 12

1.10 Secondary ionic bonds of [PCl2N]3...... 12

1.11 Chloro- and phenyl-substituted phosphazenes...... 14

1.12 Proposed structure of the complex formed between AlCl3 and [PCl2N]3...... 16

1.13 Phosphazene adducts with AlBr3...... 17

1.14 A protonated phosphazene reported by Wagner...... 20

1.15 Protonated phosphazene rings...... 22

1.16 Cyclophosphazenes coordinating to transition metals...... 23

1.17 Comparisons of P-N bond lengths of protonated and metallated cyclophosphazenes...... 25

xiii 1.18 Synthesis of a carbophosphazene adduct...... 27

15 3.1 Thermal ellipsoid plots for [PCl2 N]3. Front view(left), side view(right)...... 51

31 15 3.2 P NMR spectrum of [PCl2 N]3 in C6D6...... 52

15 15 3.3 N NMR spectrum of [PCl2 N]3 in C6D6...... 52

15 15 3.4 Thermal ellipsoid plots of [PCl2 N]3•AlBr3 (left), [PCl2 N]3•AlCl3 (bottom), 15 and [PCl2 N]3•GaCl3 (right)...... 57

31 15 15 15 3.5 P NMR spectra of [PCl2 N]3 (a), [PCl2 N]3•GaCl3 (b), [PCl2 N]3•AlCl3 (c), 15 o and [PCl2 N]3•AlBr3 (d) in C6D6 at 25 C...... 59

15 15 15 15 3.6 N NMR spectra of [PCl2 N]3 (a), [PCl2 N]3•GaCl3 (b), [PCl2 N]3•AlCl3 (c), 15 o and [PCl2 N]3•AlBr3 (d) in C6D6 at 25 C...... 60

27 15 15 3.7 Al NMR spectra of [PCl2 N]3•AlCl3 (a)and [PCl2 N]3•AlBr3 (b) in C6D6 at 25oC...... 61

31 15 3.8 Variable temperature P NMR spectra of [PCl2 N]3•AlBr3 in CD2Cl2...... 64

15 15 15 3.9 N NMR spectra of [PCl2 N]3•GaCl3 (a), [PCl2 N]3•AlCl3 (b) in toluene-d8, 15 o and [PCl2 N]3•AlBr3 (c) in CD2Cl2 at -60 C...... 65

31 15 3.10 Variable temperature P NMR spectra of [PCl2 N]3•AlCl3 in toluene-d8...... 66

31 15 3.11 Variable temperature P NMR spectra of [PCl2 N]3•GaCl3 in toluene-d8...... 67

31 15 15 3.12 P NMR spectra of [PCl2 N]3•GaCl3 (a), [PCl2 N]3•AlCl3 (b) in toluene-d8, 15 o and [PCl2 N]3•AlBr3 (c) in CD2Cl2 at -60 C...... 69

3.13 The expanded triplet of triplets at 16.5 ppm in the 31P NMR spectrum (top). 15 The Homo2DJ NMR spectrum of [PCl2 N]3•AlBr3 (bottom) in CD2Cl2. (F1 axis: 31P-31P homonuclear coupling, F2 axis: 31P-15N heteronuclear coupling)...... 70

3.14 The expanded octet of doublets at 26.2 ppm of the 31P NMR spectrum (top). 15 The Homo2DJ NMR spectrum of [PCl2 N]3•AlBr3 (bottom) in CD2Cl2. (F1 axis: 31P-31P homonuclear coupling, F2 axis: 31P-15N heteronuclear coupling)...... 71

3.15 Detailed assignment of the 31P-15N couplings from the 15 Homo2DJ NMR spectra of [PCl2 N]3•AlBr3 in CD2Cl2...... 72

xiv

15 + - 15 + - 3.16 Thermal ellipsoid plots of H[PCl2 N]3 SbCl6 and H[PCl2 N]3 AlBr4 ...... 76

31 15 15 + - 3.17 P NMR spectra of [PCl2 N]3 (a) in C6D6, H[PCl2 N]3 SbCl6 (b), and 15 + - o H[PCl2 N]3 AlBr4 (c) in CD2Cl2 at 25 C...... 78

15 15 15 + - 3.18 N NMR spectra of [PCl2 N]3 (a) in C6D6, H[PCl2 N]3 SbCl6 (b), and 15 + - o H[PCl2 N]3 AlBr4 (c) in CD2Cl2 at 25 C...... 79

31 15 + - 3.19 Variable temperature P NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2...... 80

3.20 Expanded view of the variable temperature 31P NMR spectra of 15 + - H[PCl2 N]3 AlBr4 in CD2Cl2...... 81

15 15 + - 3.21 Variable temperature N NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2...... 83

27 15 + - 3.22 Variable temperature Al NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2...... 84

31 15 + - 15 3.23 P NMR spectra of H[PCl2 N]3 AlBr4 (top) in and [PCl2 N]3•AlBr3 o (bottom) in CD2Cl2 at 25 C...... 86

31 15 + - 15 3.24 P NMR spectra of H[PCl2 N]3 AlBr4 (top) and [PCl2 N]3•AlBr3 (bottom) o in CD2Cl2 at 25 C...... 87

27 15 + - 15 3.25 Al spectra of of H[PCl2 N]3 AlBr4 (top) and [PCl2 N]3•AlBr3 (bottom) o in CD2Cl2 at 25 C...... 88

31 15 15 + - 15 3.26 P/ N HMQC spectra for H[PCl2 N]3 AlBr4 (a), [PCl2 N]4 (b), and 15 o 15 [PCl2 N]5 (c) in CD2Cl2 at 25 C. (F1 x axis: N NMR scale, F2 y axis: 31P NMR scale)...... 90

3.27 15N NMR spectrum (left) and 31P NMR spectrum (right) for 15 + - o H[PCl2 N]3 CF3CO3 in C6D6 at 25 C...... 91

+ - 3.28 Thermal ellipsoid plot of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ]...... 93

31 + - 3.29 P NMR spectrum of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ] in o C6D6 at 25 C...... 94

3.30 Quantitative 31P NMR spectrum of the residue from the synthesis of 15 o [PCl2 N]3 in C6D6 at 25 C...... 98

15 15 3.31 N NMR spectrum of the residue from the synthesis of [PCl2 N]3 in o C6D6 at 25 C...... 99

xv 31 15 15 3.32 P/ N HMQC spectrum of residue from the synthesis of [PCl2 N]3 in o 15 31 C6D6 at 25 C. (F1 y axis: N NMR scale, F2 x axis: P NMR scale)...... 100

31 15 15 o 15 3.33 P/ N HMQC spectrum of [PCl2 N]3 in C6D6 at 25 C. (F1 x axis: N NMR scale, F2 y axis: 31P NMR scale)...... 101

4.1 The structure of [Pt(PR3)2(µSiHR)]2 where R = alkyl or arly...... 103

4.2 Thermal ellipsoid plot of Si2(CH3)4(C15H9O2)2...... 114

xvi CHAPTER I

HEXACHLOROCYCLOTRIPHOSPHAZENE AND POLYPHOSPHAZENES

Introduction

In 1897, H. N. Stokes synthesized a flexible material, [PCl2N]n, that was called

“inorganic rubber” due to its unique properties. He found that [PCl2N]3, synthesized

+ - from PCl5 and NH4 Cl in refluxing sym-tetrachloroethane (Eq. 1.1), undergoes ring-

Cl Cl P N N PCl5 + NH4 Cl Cl Cl Cl2CHCHCl2 P P reflux, 13h Cl N Cl (Eq. 1.1)

o opening polymerization (ROP). When [PCl2N]3 is heated to 250 C, the polymer [PCl2N]n is formed as shown in Eq. 1.2 and has a structure as shown in Fig 1.1.1 The end groups are not known to this day. However, it is known that continued heating produces a crosslinked polymer that is insoluble in organic solvents.2 When exposed to air, this

Cl Cl [PCl N] P 250oC 2 n N N + Cl P P Cl Crosslinked Cl N Polymer Cl (Eq. 1.2)

1 spongy material becomes brittle due to hydrolysis.2 The ROP is somewhat irreproducible, with the success of the reaction being dependent on the purity of [PCl2N]3

and the presence of additives.

Cl Cl Cl Cl Cl Cl P N N P N P N P N P N P Cl Cl Cl Cl Cl Cl n

Figure 1.1. The structure of [PCl2N]n.

The chlorine substituents of this polymer can be substituted in order to tailor the polymer for specific applications. Substitution of the chlorine with trifluoroethoxy groups produces polymers having the formula [P(OCH2CF3)2N]n. The synthesis

+- responsible for this involves treating a solution of [PCl2N]3 with Na OCH2CF3. During this process, NaCl precipitates and drives the reaction to completion.2 This was the first polymer of this type to be made and it was called a poly(organophosphazene).2 Since then, other alkoxy or aryloxy groups and amino groups have been used to replace the chlorides of [PCl2N]3 to yield a wide variety of polyphosphazenes. Table 1.1 lists some

polyphosphazenes and their uses. Some polyphosphazenes are used in biological

applications. For example, some phosphazenes have been used as biomedical materials

and anticancer drug delivery systems.2 Due to the large number of applications for these polyphosphazenes, an industrial synthesis is desired. Industrial production is limited by the air sensitivity of the [PCl2N]n and a simple synthetic process has not been discovered.

Table 1.1. Applications of some polyphosphazenes.2

Formula Properties of Polyphosphazene

[P(OCH2CF3)2N]n Waterproof Fibers

Cardiovascular Replacements, Coatings for [P(OCH2CF3)2N]n and [P(OC6H5)2N]n Pacemakers and Other Implantable Devices

[P(OCH2CH2OCH2CH2OCH3)2N]n, also Solid Polymer Electrolyte & Battery

known as MEEP Technology

[P(NHCH3)2N]n Films or Drug (Cisplatin) Delivery System

[P(OC2H5)2N]n Elastomers

Biomedical Materials that Release [P(NHCH2COOCH2CH3)2N]n Antitumor Agents (Melphan)

[P(NH-aminodrug)2N]n Local Anesthetics

[P(O-(C6H4-CH2-C6H5))2N]n Optical Applications

One aspect that makes polyphosphazenes unique is the flexibility of the backbone.

This is due to the arrangement of the substituents on the polymer backbone. Specifically, the two groups bound to the phosphorus atoms orient in such a way to be farthest away from each other in a conformation called cis-trans planar as shown in Figure 1.2.2 In addition, the nitrogen atom does not have any substituents bound to it, so this aspect allows for flexibility at the nitrogen atoms. Polyphosphazenes are more flexible than organic polymers. This is due to the fact that organic polymers have substituents bound to each carbon atom in the backbone. This causes the orientation of the substituents to be 3 more limited in organic polymers because of steric considerations. Because of this

arrangement, the organic polymers are more rigid than polyphosphazenes.

Polyphosphazenes can be tailored toward specific applications where organic polymers

fail.

RR' RR'

P P N N N N P P

RR' RR'

Figure 1.2. Cis-trans conformation of polyphosphazenes.2

Polymerization.

A major route to polyphosphazenes begins with the ROP of the trimer, [PCl2N]3.

It can be purified by sublimation via vacuum at 55oC. Trace impurities or the use of a catalyst affect the yield and temperature of the ROP. Without a catalyst, the polymerization is very slow at temperatures below 230oC. The uncatalyzed ROP is usually conducted without solvent, which is called a melt polymerization. The linear polymer is soluble in common organic solvents, but becomes an insoluble crosslinked material if heated for an extended period of time or at temperatures higher than about

260oC. This crosslinked polymer only swells when exposed to organic solvents. When

o heated beyond 350 C, the polyphosphazenes depolymerize to yield [PCl2N]3, [PCl2N]4,

(tetramer), and other oligomers. Both the linear and crosslinked polymers are stable in

4 dry environments. In contact with moisture in the air, hydrolysis occurs to slowly give

ammonia, phosphate, and hydrochloric acid.

For the melt ROP, the purified trimer is placed in a glass tube that is first evacuated and then sealed. The tube is heated to 250oC for 24-48 h to produce a colorless polymer, in no more than 50-60% yield. Unreacted [PCl2N]3 acts as a solvent of the

ROP. Crosslinking begins when the concentration of [PCl2N]3 is low. The elastic linear polymer can have molecular weights of approximately 15,000.3 In addition, solutions of

o [PCl2N]3 and [PCl2N]4 in chloroform were heated to 270-300 C for about 36 h to yield polymers with molecular weights of 130,000.

The most successful polymerizations involved using the catalyst BCl3 or

BCl3●OPR3. In 1986, Sennett and coworkers experimented with the use of a catalyst to

4 assist in the polymerization. They chose BCl3 as the catalyst and trichlorobenzene for the solvent. The solution polymerization in a sealed tube was successful after 48 h at

210oC, which was a significant decrease from 250oC required without a catalyst.

Addition of an equal amount of trimer to this polymer produced a polymer having a higher molecular weight (118,000) in an apparent living polymerization. By repeating the addition of trimer, they found that longer polymers (MW = 6 x 106) could be synthesized. Throughout these experiments, the concentration of BCl3 was kept constant.

This provided a way to control the size of the polymer. The polymer yield of each step was greater than 95%.4 Molecular weights were found by light scattering measurements and gel permeation chromatography (GPC) using polystyrene standards.

The melt polymerization is somewhat irreproducible. Trace impurities, such as hydrochloric acid or water, were blamed for these irreproducible results. This continues

5 to be a problem and hinders industrial production of this polymer. It was found that if the

trimer undergoes rigorous purification, the polymerization of the trimer is slower than

trimer that is not as pure.4 Interestingly, Allcock has recommended rigorous purification of the trimer.5 Also, dry oxygen gas has been observed to act as a catalyst for this polymerization by the formation of a catalytic species some time during the process.

This led researchers to the idea that some impurity may help the polymerization process and even serve as a catalyst in the polymerization process. It is difficult to control the amounts of impurities and this is still one aspect of phosphazene chemistry that is not well understood.

Other materials have been found to serve as catalysts. Some of these include: tin, sodium, zinc, ketones, alcohols, and carboxylic acids and their salts. One characteristic these compounds share is their presumed ability to abstract a chloride from the skeletal phosphorus of [PCl2N]3 thereby, producing a phosphonium ion. A lone pair of electrons on the nitrogen of another ring is believed to attack this cation and initiate the polymerization.

The relative reactivities of the trimer and tetramer toward the ROP have been explored in recent years. It was found that [PCl2N]3 is more reactive in these polymerizations, with or without catalysts involved, compared to [PCl2N]4. [PCl2N]3 polymerizes more quickly than [PCl2N]4 which may be due to the fact that [PCl2N]3 has more ring strain and takes less heat to open. When [PCl2N]3 is contaminated with some

[PCl2N]4, the polymerization is slower. These results support the idea that ring strain is the main factor behind the polymerization of [PCl2N]3. In addition, very slow polymerization is observed for [PCl2N]5 and [PCl2N]6.

6 o [PCl2N]n can depolymerize above 350 C as shown in Fig. 1.3. At even higher temperatures, such as 600oC, it was found that a mixture of trimer, tetramer, and polymer

are produced because the reaction reaches equilibrium. Without regard to the three

starting materials, a mixture will be produced at these high temperatures. [PCl2N]n is

o known to depolymerize at 180 C to yield mostly [PCl2N]4. When the halogens

Cl Cl

PN [PCl2N]3 + [PCl2N]4 + [PCl2N]5 >350oC n

o Figure 1.3. The depolymerization of [PCl2N]n above 350 C. were completely substituted with organic units, the polymerization will not occur at any temperature.3 Catalysts were also unsuccessful in initiating the polymerization of phenyl- or phenoxy-substituted cyclophosphazenes. In general, it appears that at least four halides need to be present for a trimeric ring to polymerize. In addition, high temperatures cause other rings, such as those substituted with alkoxy or amino groups, to decompose instead of polymerizing. Only a few completely substituted alkoxy- cyclophosphazene such as 1 and 2 have been found to polymerize (Fig. 1.4).3,5

Compound 1 usually involves the spacer group -CH2O-. Proposed theories to explain why 2 polymerizes have been proved weak after experimentation, so this phenomenon is not well understood.

7 The mechanism for the ROP can be described in two different theories. The most popular theory involves the cleavage of one of the P-Cl bonds to give a phosphonium ion

3 and chloride as shown in Fig. 1.5. The lone pair of electrons on the nitrogen atom of another ring can attack the phosphorus cation, allow the ring to open, and produce a chain. The process is repeated many times to give a polymer having a repeat unit of

PCl2N, as shown in Fig. 1.5. Because the most accepted mechanism of the ROP involves

Lewis acid-base chemistry, we decided to investigate such chemistry of [PCl2N]3 in order to understand the irreproducibility of the ROP. The second mechanism involves protonation of the skeletal nitrogen atom, which in turn cleaves the N-P bond and opens the ring (Fig. 1.6). The second mechanism was proposed because traces of water are necessary for the ROP.6 Except for the initiation step, the two mechanisms of the ROP

are similar.

RO O O O P N P N N N RO OR O O P P P P N N RO OR O O

1 R = C6H5O- 2

Figure 1.4. Non-halogen containing trimeric phosphazenes that can be polymerized.3

8 Cl Cl Cl Cl P P N N N N Cl Cl P P Cl P P Cl Cl N N Cl Cl Cl 3 Cl Cl Cl Cl Cl Cl Cl P P P Cl Cl N N N N N N P Cl Cl Cl Cl P P P P P P N N Cl Cl Cl N N N Cl Cl Cl Cl Cl P P Cl Cl N Cl

Figure 1.5. The phosphonium mechanism for the ROP of [PCl2N]3.

Cl Cl Cl Cl Cl Cl P P H P H N N + H N N N N Cl Cl Cl Cl P P Cl P P P Cl N P N Cl N Cl Cl Cl Cl Cl

Figure 1.6. The protonation mechanism for the ROP of [PCl2N]3.

Bonding.

The bonding of polyphosphazenes and cyclophosphazenes has many aspects. In the first section, bonding of polyphosphazenes will be described. Bonds in the backbone of polyphosphazenes, also known as skeletal bonds, are not like other bonds commonly found for organic polymers. Each phosphorus atom has five valence electrons, engaging in four-coordinate bonding, in each repeating unit. Each nitrogen atom has five valence electrons. Because only two electrons engage in sigma bonding, the nitrogen has a lone

9 pair of electrons. These can be thought to be limited to a single sp2 orbital and, therefore, residing in a sigma bond framework.3 There is one electron left on both the nitrogen and

phosphorus atoms. The illustration in Fig. 1.7 shows this arrangement of electrons.

These two remaining electrons have been the focus of bonding theories. Both dπ-pπ

bonding or a zwitterionic structure have been proposed for the two remaining electrons.

dπ-pπ zwitterionic

NP NP

Figure 1.7. The two major bonding descriptions in one repeat unit of the

polyphosphazene chain.

A popular bonding scheme involves dπ-pπ bonding. The lone electron on nitrogen is placed in a 2pz orbital and that on phosphorus is located in a 3d orbital as shown in Fig.

1.8. Even though these π-bonds are delocalized through all three atoms, it is not possible for the electrons to be delocalized throughout the entire ring. The phosphazene ring contains nodes, areas of no electron density, which arise from a mismatch in the orbitals of each phosphorus atom. The most useful variant of this theory is known as the “island” model because the electrons are confined to a particular area of the ring called “islands”.7 10 This π-bond structure can account for the fact that most polyphosphazenes lack color and

are excellent insulators. Exceptions to this rule are those polyphosphazenes having side

groups containing chromophores or those polymers containing side groups with extended

π-conjugation.

Orbital Mismatch

↓

P1 N1 P2 N2 P3 N3 P1

Figure 1.8. Mismatch of orbitals in the skeletal bonds of trimeric cyclic phosphazenes.7

Figure 1.9 illustrates the “island” bonds, also known as banana bonds. These

“islands” prevent complete electron delocalization around the ring and the electrons are located in these regions separated by nodes. In contrast to benzene, the electrons are not fully delocalized in the π-system of the ring. This full delocalization cannot be observed for [PCl2N]3 because there are nodes.

In recent years, the dπ-pπ bonding explanation has been called into question. As pointed out by a review by Gilheany,8 d-orbitals are too high in energy to significantly participate in main group bonding. Fig. 1.10 shows the alternative zwitterionic description of [PCl2N]3, which historically was the first bonding description applied to phosphazenes. In the modern zwitterionic descriptions, electron density from the nitrogen atom is involved in a backbond to a σ* orbital of phosphorus and chlorine and, therefore, forming a π-type bond. This is termed as negative hyperconjugation.9 These zwitterionic/negative hyperconjugation descriptions explain the observed flexibility of

Figure 1.9. The “island” model of π-bonding of [PCl2N]3. polyphosphazenes. The repulsion between the positive charges on the phosphorus atoms give rise to larger angles on nitrogen, measuring greater than 109o. In conclusion, these bonding theories, including σ, ionic, or π, support the multiple bond character observed for phosphazenes.

R R P N N R R P P N R R

3 Figure 1.10. Secondary ionic bonds of [PCl2N]3.

12 Structure.

Bond Lengths. The average P-N single bond length is 1.77-1.78 Å.3 The lengths of the P-N bonds of cyclo- and polyphosphazenes are 1.54-1.62 Å, which suggest some degree of multiple bonding.9 The range of P-N bond lengths in phosphazenes has been explained with electronegativity arguments. Shorter P-N bonds are observed with the more electronegative substituents. Also, as the size of the phosphazene ring increases, the skeletal P-N bonds become shorter. For example, the bond lengths of [PCl2N]4 are shorter than those of [PCl2N]3.

Another important structural aspect involves the symmetry with respect to the substituents. When the substituents bound to the phosphorus atom of [PCl2N]3 are arranged in a symmetrical fashion, the P-N bonds are all equal in length. The arrangement does not involve distinct long and short alternating bonds. In contrast, cyclooctatetraene and boron-nitrogen heterocylces, have distinct alternating long and short bonds. However, if the substituents are not arranged symmetrically, a variety of bond lengths is observed. For example, [PPh2N]3 was found to have equal P-N bonds lengths of 1.60 Å. If two of these substituents are replaced with chlorides, the bond

3 lengths are no longer equal (P1-N2, 1.556 Å; P3-N2, 1.609 Å; P3-N4, 1.578 Å). Figure

1.11 illustrates these substituted phosphazenes. If four substituents are replaced with chloro groups, the effect is even greater.

Bond Angles. The cyclic or polymeric phosphazenes all have N-P-N angles of about 120o.3 This angle is affected by ring strain in cyclophosphazenes. The N-P-N

o o angles of [PCl2N]4 are 120.9 (ave) and slightly smaller at 118.4 for [PCl2N]3. The nitrogen atoms of the rings are more flexible and permit P-N-P angles in the range of

13 119.4-148.6o.3 With an increase in ring size, a greater angle is observed. The twelve

membered rings have even larger angles. The angles on the outside of the ring at

phosphorus (Cl-P-Cl, RO-P-OR, RHN-P-NHR, etc.) are in the range of 95-104.4o. The

o R-P-R angle was measured to be 100 for the following rings: [PF2N]3, [PF2N]4, and

o [P(NCS)2N]3. The chloro-substituted ring has a slightly larger Cl-P-Cl angle of 101.3

o and [PF2N]4 has even larger angles of 103.0 . Depending on the substituents, this angle can increase to 103-104o. Much larger angles are not observed. The N-P-N angles have not been observed to be larger than ~120o.

Ph Ph P N N Ph Ph P P N Ph Ph

Cl Cl Cl Cl P P1 N N N6 N2 Cl Ph Ph Ph 5 3 P P P P N N4 Ph Cl Ph Ph

Figure 1.11. Chloro- and phenyl-substituted phosphazenes.3

14 Phosphazenes As Bases.

15 Reactions of Lewis and Brönsted acids with [PCl2 N]3 are described in this dissertation. The first section provides a review of the coordination chemistry of

[PCl2N]3 and other phosphazenes.

Coordination Chemistry of [PCl2N]3 and Other Halogen Containing Phosphazenes.

It is known that the nitrogen of the halide substituted phosphazenes is a poor

Brönsted-Lowry base. There have been reports of complexes of [PCl2N]3 with Lewis acids: [PCl2N]3•AlBr3, [PCl2N]3•(AlCl3)2, [PCl2N]3•(SO3)3, [PCl2N]3•SbCl5,

10,11 [PCl2N]3•WCl6, and [PCl2N]3•VOCl3. The complexes had varying stoichiometry and were all air sensitive. These compounds were poorly characterized by modern standards and lacked x-ray crystallographic structure determinations.

In 1942, Bode and coworkers reported an adduct having the formula,

[PCl2N]3●2AlCl3. The [PCl2N]3 was dissolved in CS2 and this solution was shaken for 3 h with AlCl3. The solution was filtered to give a pale yellow residue that could not be recrystallized. The ratio of phosphorus to chlorine was 1:4 and consistent with the

12 formula [PCl2N]3●2AlCl3. No other characterization was performed. The structure of the compounds has been subject to debate, the adduct structure being largely favored over a phosphonium ion [P3Cl5N3][Cl(Lewis acid)]. For example, there is some speculation that AlCl3 reacts with [PCl2N]3 to remove chloride and give ionic species such as

[P3Cl5N3]AlCl4 or [P3Cl5N3]2[AlCl4]2 (Fig. 1.12) in the Friedel-Crafts substitution of

11,13 [PCl2N]3.

15 Cl Cl - - [AlCl 4 ] [AlCl 4 ] P P 2 N N N N Cl Cl Cl P P P P Cl N Cl Cl N Cl

Figure 1.12. Proposed structure of the complex formed between AlCl3 and [PCl2N]3.

14 In 1969, Sowerby and coworkers reported an adduct of [PCl2N]3 with AlBr3.

Equimolar solutions of [PCl2N]3 and AlBr3 in CS2 were combined, allowed to stand, and colorless crystals formed. These crystals were isolated, but purification via sublimation was not successful. The melting point (174oC) and the elemental analysis provided

14 evidence to support the proposed formula, [PCl2N]3●AlBr3. The IR spectrum (Nujol mull, cm-1) showed strong bands: 1280, 1215, 950, 773, and 645. No other characterization was done for [PCl2N]3●AlBr3. This product must be handled cautiously because it hydrolyzes if exposed to atmospheric moisture. When [PCl2N]3●AlBr3 was placed into a glass tube, sealed under vacuum, and heated to 180oC, a thick liquid was produced having a broad band (1300 cm-1) in the IR spectrum. This supported the presence of a linear species, possibly a short polymer, with the formula,

Br(PCl2N)3AlBr3. No 2:1 adducts with AlBr3 could be produced, possibly because the

1:1 adduct precipitates immediately.

Equimolar solutions of [PBr2N]3 and AlBr3 in CS2 were mixed producing an exothermic reaction. White crystals precipitated from this solution and were washed with

o CS2. The crystals were purified via sublimation at 130 C to yield a solid having a melting point of 180-182oC. Elemental analysis and the IR spectrum of these crystals provided 16 14 evidence for the adduct having the formula [PBr2N]3●AlBr3 (Figure 1.13). For

[PBr2N]3, a 2:1 adduct with AlBr3 could be produced in 73% yield and had a similar

melting point (180oC) to the 1:1 adduct. This is also higher than that found for

o [PCl2N]3●AlBr3 (174 C). Elemental analysis provided evidence for [PBr2N]3●2AlBr3, a

1:2 adduct. Further studies showed that a 1:3 adduct could not be isolated, suggesting that the 1:2 adduct precipitates quickly before the 1:3 adduct could form, regardless of the amount of AlBr3 added in the reaction. This characteristic also inhibited a 2:1 adduct

for [PCl2N]3 with AlBr3.

Br Br Cl Cl AlBr3 P P AlBr3 N N Br N N Br Cl Cl P P P P Br N Br Cl N Cl

14 Figure 1.13. Phosphazene adducts with AlBr3.

These adducts of [PCl2N]3 with AlBr3 had a proposed dative bond, N→Al, as

shown in Fig. 1.13. It was concluded that if the substituents bound to the phosphorus are

electron-withdrawing groups and the phosphazene comes in contact with strong Lewis

acids, then this interaction will form. On the other hand, if the substituents are electron

donating groups, the complex can be made with the weaker Lewis acids.

Other adducts have been reported with these rings. In 1948, Bode synthesized a

15 protonated phosphazene having the formula [PCl2N]3●HClO4. In 1977, Kravchenko reported the synthesis of two complexes of the Lewis acids SbCl5 and TaCl5 with

17 16 [PCl2N]3. The first complex precipitated from CCl4 in a 1:1 stoichiometry, regardless of the reagent ratio. The tantalum complex was obtained from the melt of [PCl2N]3 with

TaCl5. The complexes were formulated as the phosphonium ion salts [P3N3Cl5][SbCl6] and [P3N3Cl5][TaCl6] based on NQR characterization of the anion. Characterization was limited to elemental analysis, IR, and NQR spectroscopies. This lack of characterization caused doubt of these syntheses. For example, Coxon reported that [PCl2N]3●SbCl5

14 could not be isolated from reactions of SbCl5 with [PCl2N]3 in CCl4. Some doubt could also be place for Kandemirli’s work involving the reaction of VOCl3 with [PCl2N]3 in

17 CH2Cl2 to yield [PCl2N]3●VOCl3. Characterization included IR and ESR spectroscopy and elemental analysis, but no NMR spectroscopy or x-ray crystallography was conducted on the product of this reaction. One interesting feature of this work was that

[PCl2N]3●VOCl3 was reported as a stable compound by molecular orbital theory and

17 calculating the binding energy. Another reported adduct, [PCl2N]3●(SO3)3, was not characterized by modern techniques. The reaction of [PCl2N]3 with SO3 yielded a thick liquid that was reported as a phosphazene adduct.18 In addition, no adducts formed for

[PCl2N]3 with SnCl4 in CS2. Also, solutions of SnCl4, BBr3, CH3I, or TiCl4 in CS2 did not yield adducts when combined with solutions of [PCl2N]3. In summary, complexes of the weak base, [PCl2N]3, have been reported with several strong Lewis acids and the

super Brönsted acid HClO4. Because X-ray crystallography, NMR spectroscopy, and other modern techniques were not used to characterize these complexes, there has been some doubt whether the interpretations are correct.

18 Coordination Chemistry of Other Phosphazenes.

A review of certain aspects of the coordination chemistry will be presented in this

subsection. The emphasis of the review will be on literature precedents for the chemical

reactions. NMR data and structural parameters will be presented in the results and

discussion section.

The roles that cyclophosphazenes play in coordination chemistry include: 1)

cyclophosphazenes can engage in reactions to produce ionic salts via protonation, 2) the

nitrogen atom on the ring can coordinate to a metal, and 3) a metal can coordinate to the phosphorus atom on the ring. In some cases, the first and second interaction can occur simultaneously. The latter interaction is described as a covalent bond of the phosphorus atom to the transition metal. This aspect does not apply to this work, so it will not be mentioned further.

In 1968, Wagner synthesized a protonated phosphazene as shown in Fig. 1.14.

The P-N single bonds were 1.67 Å. This is longer than the other P-N bonds of the ring.

The other P-N bonds in the ring were shorter at 1.57 Å, supporting the multiple bond trend found in the other examples described earlier.

Protonation of a cyclophosphazene often involves reactions of the cyclophosphazenes with transition metal reagents to produce a species that does not have a direct bond to the metal. The metal serves as a counter ion in theses cases and the source of the proton appears to be hydrolysis of the metal reagent. Figure 1.15 illustrates

+ 2- + - three examples: [HN3P3(NMe2)6] 2 [X] where X = Mo6O19 or CoCl4, H[PR2N]3 Cl

2+ 2- 19 where R = N(i-Pr)H, and [H2N5P5(Me)10] [CuCl4] . The three complexes involve amino and alkylphosphazenes that are far more basic than [PCl2N]3. With these

19 compounds, it is important to note that the anion interacts with the protonated ring by hydrogen bonding through the N-H bond of the cyclophosphazene. Therefore, the species have been considered ionic salts.

H R N R R PPR N N P R R R = N(iPr)H Figure 1.14. A protonated phosphazene reported by Wagner.

The nitrogen atom of the cyclophosphazene can interact with transition metals through its lone pair of electrons. If electron releasing substituents are bound to the phosphorus atom, then the basicity of the nitrogen atom of the ring increases. The basicity of the skeletal nitrogen atom can be compared in various compounds. For example, it was found that the nitrogen atoms of the ring of amino cyclophosphazenes, having the formula, [NP(NRR’)2]3, are more basic than the amino substituents. This trend is not the only factor to consider. As the size of the ring increases, the nitrogen atom is more readily available for contact in a reaction with transition metals. The ring is more flexible as the size increases and, therefore, more available to coordinate with transition metals. This phenomenon has been observed with larger rings, N4P4(NMe2)8,

N4P4(NHMe)8, N4P4Me8, N6P6Me12, N6P6(NMe2)12, and N8P8Me16. These large rings formed complexes with transition metals, but it was found that some ligands

(N3P3(NMe2)6 or N3P3(NHMe)6) did not bind to transition metals, presumably due to the

limited flexibility of the smaller six membered rings versus the larger eight membered

20 rings. In addition, the nitrogen atom of a ring showed sufficient basicity to bind to a copper species. In a reaction of an eight-membered phosphazene, N4P4Me8, with CuCl2, the complex [HN4P4Me8CuCl3] is formed (Fig. 1.16). The CuCl3 is bound to the nitrogen atom of the ring and the opposing nitrogen atom is protonated.

Even though the rings, N4P4Me8 and N4P4(NHMe)8, showed no reactivity to copper, it was found that complexes were successfully synthesized with PtCl2. The platinum atom coordinates to two nitrogen atoms of the ring and the structure is as shown in Figure

1.16. It was concluded that the incoming metal could fit in this way because of the flexibility of the ring, as shown in Figure 1.16. This phosphazene was compared to organic macrocycles because of their similar reactivity to PtCl2. Other complexes had been made with PdCl2 and PtCl2 with the hexamer, N6P6Me12, as shown in Figure 1.16.

The metal is coordinated to two nitrogen atoms of the phosphazene ring forming a

19 chelating ring system. Other rings such as N6P6(NMe2)12 have served as ligands to copper and cobalt. For either metal, it was found that four nitrogen atoms of the ring are coordinated to either metal. When a nitrato ligand was used, the cobalt was coordinated by four nitrogen atoms of the phosphazene ring as well as two oxygen atoms of the nitrato ligand. Not all phosphazene rings are useful ligands. For the very large ring systems, it was found that they serve as acceptable ligands to metals. Few examples of large ring complexes are available because isolation of the higher-membered rings has proved to be a challenge.

When a phosphazene is protonated or forms a complex with a metal, some changes occur in the ring’s structure, as evidenced by differences in the bond lengths and

+ Me N 2 NMe2 P N N [X]2- Me2N NMe2 P P Me N N X = Mo O or 2 NMe2 6 19 CoCl4 H 2

+ H R N R Cl - R PPR N N R = N(i-Pr)H P R R

Me Me 2+ H P Me N N Me P P Me 2- Me [CuCl4] N N Me P P Me N Me Me H

Figure 1.15. Protonated phosphazene rings.19

Me H Me P N P Me Me N N Me Me P N P

Me Me Cu

Cl Cl Cl

R R

R P N P R Cl Cl Pt R = Me or NHMe N N

R PN P R

R R

Me N Me P P Me Me Me N N Me P M P Me Cl Cl Me N N N P P M = Pt or Pd Me Me Me Me

Figure 1.16. Cyclophosphazenes coordinating to transition metals.1

23 angles. Bond lengths have been measured and compared to unprotonated rings (Fig.

1.17). The unprotonated ring, N3P3(NMe2)6, has a P-N bond length (1.579(21) Å, ave), which is shorter than the protonated ring (1.669(8) Å, ave).20 This suggests that the unprotonated rings have multiple bond character which is lost at the P-N bond that flanks the H+ once protonation occurs. The P-N bonds of the nitrogen atom that flanks the platinum of the metallated phosphazene, N4P4Me8●PtCl2, are 1.672(6) and 1.645(6) Å, indicating single bond character.21 In addition, a combination of effects can be the reason

for increasing bond lengths. In the ring, [HN4P4Me8CuCl3], both metallation and protonation of phosphazene nitrogen atoms have occurred. It was found to have longer

P-N bond lengths at both the protonated and metallated nitrogen atoms. The P-N bond lengths for N4P4Me8 were 1.600 Å (ave) shorter than those P-N bonds in the protonated system. The P-N bonds that flank the protonated nitrogen atom were in the range

1.665(20) and 1.670(20) Å. The P-N bonds of the nitrogen atom that flanks the copper were 1.631(20) and 1.638(20).22 In 1997, studies were conducted to measure the binding energy of the adduct, [PR2N]3●AlF3 (R = H, OH). They found that the strongest binding in this complex occurs through the Al-N bond. The energies for the Al-N couple and were found to be -67 and -47 kcal/mol.23 From this study, it was concluded that if the nitrogen of the phosphazene ring is not sterically hindered by the R groups on phosphorus, then this nitrogen would be the preferred binding site for Lewis acids.

In 2003, Manners described adduct formation with GaCl3 with a cyclic

24 carbophosphazene. GaCl3 was reacted with the eight membered ring [(Cl3P=N)ClPNC-

(Ph)NP(Cl2)NC(Ph)N], 4, in CHCl2 for 16 h. To this transparent solution, hexanes was

24 Me N NMe + 2 2 Me2N NMe2 P 1.588 P 1.675 H N N N N Me N Me2N NMe2 2 NMe2 P P P P Me2N N Me2N N NMe NMe2 2 2

2- [Mo6O19]

Me Me Me Me P N P P N P Me Me Me Cl Cl Me 1.591 1.672 Pt 1.645 N N N N Me Me Me Me P N P P N P Me Me Me Me

Me H Me 1.670 1.665 P N P Me Me N N Me Me P N P 1.631 1.638 Me Me Cu Cl Cl Cl Figure 1.17. Comparisons of P-N bond lengths of protonated and metallated

cyclophosphazenes.19

25 added and crystals were observed after 2 days. The crystals were washed with hexanes

and dried to yield the six membered ring, 5, as shown in Figure 1.18. This compound

was characterized by NMR spectroscopy, mass spectrometry, and x-ray crystallography,

and elemental analysis.

The 31P NMR spectroscopy of 5 showed three broad resonances having a

downfield chemical shift from those observed for 4, consistent with three different

phosphorus atoms. The x-ray crystal structure of 5 showed a dative Ga-N bond at

1.997(2) Å. The P-N distances that flank the Ga-N bond of 5 are lengthened from the P-

N distances of 4 and correspond to single bonds.

The ring contraction in Fig. 1.18 was unexpected. The P-Cl bond, at the

phosphorus atom bound to the N=PCl3 group of 4 was longer than the other P-Cl bonds

in 4.24 With this knowledge, Manners and coworkers predicted that this chlorine atom

- would be easily removed as Cl by GaCl3 to yield a phosphonium cation and a

tetrachlorogallate anion. This reaction was studied because it is believed that

phosphonium cations serve as intermediates in the ROP of these heterophosphazenes.

This product was one of only a few rare examples of adduct formation for

heterophosphazenes. The reason why 5 was produced involves the reactivity of the lone

pair of electrons at the ring nitrogen atom. The N=PCl3 group was known to donate

electrons into the ring and, therefore, it increased the basicity of the nearby ring nitrogen

atom.

This dissertation will describe the acid-base chemistry of [PCl2N]3 involving both

Lewis and Brönsted chemistry. The adducts were characterized with several techniques.

NMR spectroscopy, including multinuclear and multidimensional experiments, will be

26 presented. X-ray crystallography was critical in the determination of the structure of the

adducts. These results will be compared to previous descriptions found in literature.

Cl N PCl3 P Cl N PCl3 N N Cl3Ga P Ph C C Ph N N GaC l 3 Cl P C N N RT P N Ph Cl Cl Cl 4 5

Figure 1.18. Synthesis of a carbophosphazene adduct.24

27 References and Notes

1) Allcock, H. R. In Synthesis and Characterizations of Poly(organophosphazenes); Gleria, M.; DeJaeger, R., Eds.; Nova Science: New York, 2004; Chapter 1.

2) Allcock, H.; Mark, J.; West, R. “Polyphosphazenes” Inorganic Polymers, Prentice Hall: New York, 1992, Chapter 3.

3) Allcock, H. Chem. Rev. 1972, 72, 315-356.

4) Sennett, H.; Singler, R.; Willingham, R. In Organic and Organometallic Polymers; Allcock, H.; Wynne, K.; Zeldin, M. Eds.; American Chemical Society: Washington, D.C., 1988, Chapter 20.

5) Allcock, H. Chemistry and Applications of Polyphosphazenes; Wiley & Sons: New York, 2003; Chapter 5.

6) Emsley, J.; Udy, P. Polymer, 1972, 13, 593-594.

7) Allcock, H.; Mark, J.; West, R. “Polyphosphazenes” Inorganic Polymers, Prentice Hall: New York, 1992, Chapter 3.

8) Gilheany, D. Chem. Rev. 1994, 94, 1339-1374.

9) Allcock, H. Chemistry and Applications of Polyphosphazenes, Wiley & Sons: New York, 2003, Chapter 12.

10) Allcock, H. R. “Complex and adduct formation,” Phosphorus-Nitrogen Compounds, Academic: New York, 1972; Chapter 11.

11) (a) Coxon, G. E.; Sowerby, D. B. J. Chem. Soc. A 1969, 3012-3014. (b) Bode, H.; Bach, H. Chem. Ber. 1942, 75B, 215-226. (c) Goehring, M.; Hohenschutz, H.; Appel, R. Z. Naturforsch. 1954, 9b, 678-681.

12) Bode, H.; Bach, H. Chem. Ber. 1942, 75B, 215-226.

13) Allcock, H. R. “Friedel-Crafts substitutions” Phosphorus-Nitrogen Compounds, Academic: New York, 1972; Chapter 10.

14) Sowerby, D.; Coxon, G. J. Chem. Soc. A 1969, 3012-3014.

15) Bode, H.; Bütow, K.; Lienau, G. Chem. Ber. 1948, 81, 547-552.

16) Kravchenko, E.; Levin, B.; Bananyarly, S.; Toktomatov, T. Koordinatsionnaya Khimiya, 1977, 3, 374-379.

17) Kandemirli, F. Phos. Sulfur, Silicon and the Rel. Elem. 2003, 178, 2231-2342.

18) Goehring, M.; Appel, R.; Honenschutz, H. Z. Naturforscg, 1954, 9b, 678-681.

19) Chandrasekhar, V.; Krishnan, V. In Applicative Aspects of Cyclophosphazenes; Gleria, M., DeJaeger, R., Eds.; Nova Science: New York, 2004; Chapter 7.

20) Allcock, H.; Bissell, E.; Shawl, E. Inorg. Chem. 1973, 12, 2963-2968.

21) Allcock, H.; O’Brien, J.; Allen, R. Inorg. Chem. 1979, 18, 2230-2235.

22) Trotter, J.; Whilow, S. J. Chem. Soc. A 1970, 455-459.

23) Waltman, R.; Lengsfield, B.; Pacansky, J. Chem. Mater. 1997, 9, 2185-2196.

24) Manners, I.; Chivers, T.; Lough, A.; Rivard, E. Inorg. Chem. 2004, 43, 802-811.

29 CHAPTER II

EXPERIMENTAL SECTION

General Procedures. All manipulations were preformed under argon, nitrogen, or vacuum using standard anaerobic techniques unless otherwise stated.1,2 The vacuum line had an ultimate capability of 2x10-4 torr. Elemental analyses were conducted by

Microanalysis Laboratory (Urbana, IL). All glassware was dried in the oven overnight

(~120oC) unless specified otherwise. Unless otherwise stated, reaction apparati were

either assembled hot and immediately subjected to vacuum on the Schlenk line or the hot

glassware was placed in the port of the glove box and immediately evacuated before

assembly in the glove box. The glassware used for the experiments was made with

virtually greaseless Fisher-Porter Solv-seal glass joints. High vacuum valves on the

flasks were purchased from Kimble-Kontes. Lewis acids, [PCl2N]3, and their adducts were stored in separate desiccators in the glove box. For syntheses involving light sensitive compounds in solution, light was minimized by wrapping the flasks with foil.

The flasks were put into a cardboard box that was covered with black felt to further minimize exposure to light. For crystal growth, the solution was allowed to stand in this box, which was left undisturbed on the lab shelf, for several days. After purifying starting materials or isolating light sensitive products, the compounds were put into vials with snap caps to create a tighter seal than screw caps. These vials were wrapped in foil

30 and then stored in desiccators inside the glove box. By glassblowing, NMR tubes for polymerizations were made having a joint connected so they could be attached to the

Schlenk or vacuum lines. The tubes were sealed under vacuum for melt polymerization

reactions. For NMR spectroscopy, tubes were sealed under vacuum in order to preserve samples for an extended period of time.

Materials. Sym-tetrachloroethane (Aldrich) was stirred overnight in H2SO4, washed with NaHCO3, washed with distilled H2O, dried with CaCl2, and dried over P2O5 unless stated otherwise. C6D6 (Aldrich) was dried three times with freshly activated 4Å molecular sieves and stored under argon. Methylene chloride and hexane (both Fisher) were dried and deoxygenated by alumina and copper columns in the Pure Solv solvent system (Innovative Technologies, Inc), unless stated otherwise. CD2Cl2 (Cambridge

Isotopes) was stirred over P2O5 and dried three times with freshly activated 4Å molecular

+ - 15 sieves and stored under argon. NH4 Cl (Fisher), NH4Cl (Cambridge Isotopes), P1-t-

15 Bu-tris(tetramethylene) (Fluka), and PCl5 (Aldrich) were used as received. The % N in

15 the NH4Cl salt was determined using FAB spectrometry. This salt was found to be

15 14 97.02% N and 2.98% N. The Aldrich or products, BiCl3, BBr3, B(C6F5)3, BCl3, WCl6,

PCl5, CS2, AgSO3CF3, triflic acid and AgCB11H6Br6 (Strem) were used as received.

SbCl5 (Aldrich) was used as received due to its reaction with valves on the vacuum line during an attempt to purify it. Et3N (Fisher) was distilled from BaO. The Lewis acids,

AlCl3, AlBr3, InCl3 (Aldrich) and GaCl3 (Strem), were purified via sublimation prior to use.

Routine Spectroscopy. The infrared spectra were collected on a Nicolet Nexus

870 Fourier transform spectrometer. The instrument was equipped with a Thunderdom

31 ATR accessory. The NMR spectra were obtained using a Gemini 300 MHz, INOVA 400

MHz, or 750 MHz spectrometers. The 31P, 15N, and 27Al NMR spectra were referenced to 95% phosphoric acid (0 ppm), 100% ammonium nitrate (0 ppm), and 100% aluminum hexaqua ion (0 ppm). The 1H NMR spectra were referenced to the proton resonance in

the deuterated solvents. The 13C NMR spectra were referenced to the carbon resonance in the deuterated solvents.

The following four paragraphs that describe the 2D NMR spectroscopy were written by Debasish Banerjee. The 31P-31P homonuclear J-resolved spectroscopy

15 31 (Homo2DJ) experiment of [PCl2 N]3•AlBr3 was acquired at -60ºC using a 8.1 µs P π/2 pulse width and 0.365 s acquisition time, a relaxation delay of 1.5 s were used. A 2271

Hz spectral window was used for the direct (31P) dimension whereas a 150 Hz window was used for the indirect (J) dimension. For each of the 2×256 t1 increments in the indirect detection axis (f1) 32 transients were averaged. Data were zero filled to provide a 4096×512 data matrix and processed using sinebell and shifted sinebell weighting functions.

31 15 15 The P- N HMQC experiment of [PCl2 N]3 was acquired at 25ºC using the

Varian HPN triple resonance probe at 750 MHz instrument. A 13.2 µs 31P π/2 pulse, a

0.169 s acquisition time, and a relaxation delay of 1 s were used. A 12.1 KHz spectral window was used for the direct (31P) dimension whereas a 6 kHz window was used for

15 the indirect ( N) dimension. For each of the 2×64 t1 increments in the indirect detection axis (f1), 8 transients were averaged. Data were zero filled to provide a 8192×512 data matrix and processed using sinebell and shifted sinebell weighting functions.

32 31 15 15 The experimental parameters for the P- N HMQC spectrum of [PCl2 N]n were as following: pulse widths 13.2 µs and 78 µs were used for the 31P and the 15N channels, respectively, using the same probe at 750 MHz. The 16 transients were averaged for each of the 2×128 complex fid’s and a 1 s relaxation delay was used. A 12.1 KHz spectral window was used for the direct (31P) dimension whereas a 5.8 kHz window was used for the indirect (15N) dimension. The data were processed using sinebell and shifted sinebell weighting functions and zero filled to 4 times the original data size to improve the quality of the spectra. Linear prediction was used in the f1 dimension to improve resolution.

31 15 15 + - The P- N HMQC spectra of H[PCl2 N]3 AlBr4 were collected using the same pulse widths and spectral window in the two channels and the same probe at 750 MHz.

The 16 transients were averaged for each of the 2×64 complex fid’s and a 1 s relaxation delay was used. The data were processed using sinebell and shifted sinebell weighting functions and zero filled to 4 times the original data size.

X-ray crystallography. In the glove box, crystals were put into paratone oil on a

slide. The slide was placed into a desiccator and then wrapped in foil to minimize

exposure to light as it was carried downstairs to the instrument. The crystals were

immediately mounted in low light and the data collection took place with the laboratory

lights turned off, unless stated otherwise.

Crystal structure analyses were done by Matthew Panzner. Crystal structure data

sets were collected on a Bruker Apex CCD diffractometer with graphite-monochromated

Mo Kα radiation (λ = 0.71073 Å). Unit cell determination was achieved by using

reflections from three different orientations. An empirical absorption correction and

33 other corrections were done using multi-scan SADABS. Structure solution, refinement and modeling were accomplished using the Bruker SHELXTL package.3 The structures were obtained by full-matrix least-squares refinement of F2 and the selection of appropriate atoms from the generated difference map.

15 Preparation of [PCl2 N]3. The solvent sym-tetrachloroethane (70 mL) stirred

15 over P2O5 and was filtered in air to a graduated cylinder. In air, NH4Cl (10.001 g, 183.5 mmol) was added to a 500 mL size Schlenk flask. PCl5 (38.212 g, 183.5 mmol, caution, very water sensitive) was added to the flask and sym-tetrachloroethane (70 mL) was decanted from the graduated cylinder into this flask. A CaCl2-filled drying tube and a reflux condenser were attached to the flask. The entire apparatus was placed into a pre-

o heated sand bath at 120 C and set to stir. The argon flow was turned off to prevent PCl5 from subliming into the tubes of the Schlenk line. The heat was slowly increased and after 2 h and 20 min, the temperature was stable at 169oC. The solution was allowed to reflux for 17.5 h to yield a medium yellow transparent solution. A white powder was slowly filtered from the cooled solution to give a golden yellow filtrate. The flask containing the filtrate was filled with argon. Because the solvent is sensitive to light, this flask was covered with foil allowed to stand overnight. In air, the filtrate was placed into a 25 mm x 500 mm tube, which served as a sublimator. The solvent was removed in a fashion that minimized bumping on vacuum line in minimal light. This left a mixture of colorless crystals on top and a small amount of oily materials on the bottom. The sublimation took place at ~60oC over a period of 17 days. The transparent plate crystals

31 15 (5.035 g) were collected in the glove box and the P NMR showed ~98% [PCl2 N]3 and

15 ~2% [PCl2 N]4. A second tube sublimation was conducted using the same procedure as

34 before. Plate-shaped colorless crystals (4.567 g, yield = 46%) were collected after 8

31 15 days. The P NMR spectrum showed ~99% [PCl2 N]3, Mp = 113-114°C. IR (Nujol

-1 31 mull) cm : 1194 (s), 1173 (vs), 862 (w), 721(w), 609 (s), 525 (s). P NMR (C6D6): δ

3 1 15 20.6 ppm (apparent d of t, JP-N = 18 Hz, JP-N = 22 Hz), N NMR (C6D6): δ 102.3 ppm

(m). For X-ray crystallographic information, see the Appendix.

X-ray analysis of the unsublimed crystalline material found in the bottom of the

15 15 31 tube proved to be a mixture of [PCl2 N]3 and [PCl2 N]4. P NMR spectroscopy of the amorphous material in the bottom of the tube indicated that the majority (~89%) was

15 15 short-chain [PCl2 N]n (δ -17.4 ppm, MW = 2593) mixed with ~6% [PCl2 N]6 (δ -14.6

15 ppm), and ~1% [PCl2 N]4 (δ -5.6 ppm). Resonance at δ -16.6 ppm (~3%) is tentatively assigned as the end group of the polymer. 15N NMR indicated two resonances for

15 [PCl2 N]n, ~91% (δ 203.7 ppm) and ~9% (δ 203.8 ppm).

15 Syntheses of [PCl2 N]3●MX3 (M = Al, X = Cl or Br; M = Ga, X = Cl) adducts.

Purification of AlBr3. In the glove box, AlBr3 (5 g in a sealed glass ampule) was placed in a sublimator. The sublimation was conducted at 55-74oC with 72oC as the optimal temperature and using a dry ice/acetone cold finger. After 2 h and 20 min, about

4.5 g of purified AlBr3 was collected.

15 Preparation of [PCl2 N]3•AlBr3. Because AlBr3 solutions are somewhat light sensitive, exposure to light was minimized. High vacuum line techniques were used as much as possible instead of the Schlenk line because other undesired products can be

4 15 produced. In the glove box, [PCl2 N]3 (0.100 g, 0.285 mmol) was dissolved in 20 mL of hexane and AlBr3 (0.076 g, 0.285 mmol), purified as described above, was added to

give a clear solution that quickly turned cloudy. The solution was allowed to stand 35 undisturbed for 2 days and colorless crystals formed, some of which were suitable for x- ray diffraction. The volatiles were removed on the vacuum line at -15°C to give 0.083 g

15 -1 [PCl2 N]3•AlBr3 (~83%). Mp: 177-178°C. IR (Nujol mull cm ): 1301 (m), 1236 (m),

1194 (s), 1173 (vs), 1084 (w), 1020 (w), 942 (m), 851 (m), 757 (m), 722 (m), 688 (w),

15 667 (w), 640 (m), 626 (m), 609 (s), 525 (s). Anal. calcd. for [PCl2 N]3•AlBr3: P,

31 15.05%; Al, 4.37%. Found: P, 15.13%; Al, 4.55%. P NMR (C6D6, ppm): δ 27.1 pm

15 27 (b, s), 16.8 ppm (b, s), N NMR (C6D6): δ 93.3 ppm (m, unresolved), Al NMR (C6D6):

δ 94.0 ppm (b, s, FWHM = 423 Hz). For X-ray crystallography information, see the

Appendix.

15 Preparation of [PCl2 N]3•AlBr3 in CH2Cl2. In the glove box, a solution of

15 [PCl2 N]3 (0.400 g, 1.141 mmol) and 50 mL of CH2Cl2 was prepared. AlBr3 (0.304 g,

1.141 mmol), purified as described above, was added, the solution was swirled and the flask was wrapped in foil. After 45 min, the solution was light yellow. The flask was brought out of the glove box and allowed to stand for 5 days in the dark. The volatile components were removed at ~12oC (methanol/ice). Crystals were found to be twinned and this structure could not be solved. Further characterization showed that this was the

15 15 same adduct previously synthesize in hexane, [PCl2 N]3•AlBr3 with [PCl2 N]3 and

15 31 [PCl2 N]4 as minor impurities. Yield ~ 80%. P NMR (CD2Cl2, ppm): δ 27.2 (b, s), δ

15 21.5 (b, m), δ 17.6 (b, m), δ -5.4 (s), δ -13.0 (s). N NMR (CD2Cl2, ppm): δ 110.4 (b,

27 m), δ 105.5 (b, m), δ 97.1 (b, m), δ 96.5 (b, m). Al NMR (CD2Cl2, ppm): δ 106.0 (b, s,

FWHM = 427 Hz).

15 Further characterization of [PCl2 N]3•AlBr3. Low temperature NMR studies were conducted on this adduct in CD2Cl2. The coupling constants were determined using 36 a P-P/15N-P homonuclear coupling 2D experiment (Homo2DJ) at -60oC. 31P NMR (δ, ppm) 25oC: 27.2 (b, s), 21.5 (b, m), 17.6 (b, m), -5.4 (s), -13.0 (s); 0oC: 26.9 (b, s), 21.3

(b, m), 19.7 (b, m), 18.2 (sh), 17.2 (b, m), -5.0 (s), -13.4 (b, s); -20oC: 26.5 (b, m), 20.9

(b, m), 19.3 (b, m), 16.8 (b, m), -4.4 (s), -40oC: 26.4 (b, m), 20.9 (b, m), 19.3 (b, m), 16.8

o 2 1 (b, m), -4.3 (s); -60 C: 26.2 (o of d, JP-P = 44 Hz & 8.5 Hz, JP-N = 27.5 Hz & 20.5 Hz),

2 1 20.9 (b, m), 20.6 (b, m), 19.1 (b, m), 16.5 (t of t, JP-P = 44.5 Hz, JP-N = 19 Hz), -3.8 (s);

o 2 1 -80 C: 25.9 (o of d, JP-P = 44.9 Hz & 8.7 Hz, JP-N = 21.4 Hz & 16.8 Hz), 20.6 (b, m),

2 1 15 20.3 (b, m), 18.9 (b, s), 16.2 (t of t, JP-P = 44.9 Hz, JP-N = 18.8 Hz), -3.3 (b, s). N

o 1 3 NMR (ppm) -60 C: 94.7 (d of t, JP-N = 18.5 Hz, JP-N = 8.5 Hz).

Purification of GaCl3. In the nitrogen glove bag, GaCl3 (~5.5 g anhydrous granular solid) was placed in a sublimator. The sublimation was conducted at 45-47oC for 1 h using a dry ice/acetone cold finger. In the glove box, 5.00 g of purified GaCl3 was collected and stored.

15 15 Preparation of [PCl2 N]3•GaCl3. In the glove box, [PCl2 N]3 (0.200 g, 0.570 mmol) was dissolved in 30 mL of hexane at RT. GaCl3 (0.102 g, 0.579 mmol) was added to give a clear solution that turned cloudy after 10 min. The solution was stirred for 12 days and colorless crystals, which were suitable for x-ray diffraction, were deposited.

The mixture of crystalline and powdery solids was isolated by filtration under vacuum.

Both the crystals and precipitate were identical and were obtained in a total yield of

~80%. Mp = 130-133°C. IR (Nujol mull) cm-1 1194 (s), 1173 (vs), 722 (m), 680 (w),

15 666 (m), 609 (s), 525 (s). Anal. calcd. for [PCl2 N]3•GaCl3: P, 17.64%; Ga, 13.24%.

31 Found: P, 16.75%; Ga, 13.21%. P NMR (CD2Cl2): δ 23.4 ppm (b), δ 23.3 ppm (b, sh)

37 15 N NMR (CD2Cl2): δ 95.9 ppm (m, unresolved). For X-ray crystallographic

information, see the Appendix.

15 Further characterization of [PCl2 N]3•GaCl3. Low temperature NMR studies

31 o o were conducted on this adduct in toluene-d8. P NMR (ppm) 25 C: 22.6 (b, s); 0 C:

22.3 (b, s), -20oC: 22.4 (broader, s), -40oC: 32.2 (b, sh), 25.5 (b, m), 22.0 (b, overlapped), 18.3 (b, m), -60oC: 26.2 (b, s), 19.8 (b, s), 16.6 (b, s); -70oC: 26.1 (b, s),

19.9 (b, s), 16.4 (b, m). 15N NMR (ppm) -60oC: 96.4 (b, m), 84.2 (b, m).

Purification of AlCl3. In the glove box, AlCl3 (5 g in a sealed glass ampule) was placed in a sublimator. A small piece of glass wool (dried in the oven for 15 min.) was placed on top of the AlCl3 to serve as a barrier to prevent any Al2O3 on the surface from rising up with the sublimate. The sublimation was conducted at 65-95oC with 84oC as the optimal temperature. After 24 h, about 2.5 g of purified AlCl3 was collected.

15 Preparation of [PCl2 N]3•AlCl3. Because AlCl3 solutions are somewhat light sensitive, exposure to light was minimized. High vacuum line techniques were used

15 instead of the Schlenk line. In the glove box, a solution of [PCl2 N]3 (0.400 g, 1.141 mmol) and 40 mL of hexane was prepared. AlCl3 (0.153 g, 1.141 mmol) was added and the solution quickly turned cloudy. The solution was swirled for 1 min and allowed to stand. The flask was brought out of the glove box and allowed to stand for 5 d in the dark. Small crystals were observed on the sides and in the bottom of the solution. A few of these crystals were used for the crystal structure determination of the adduct,

15 [PCl2 N]3•AlCl3.

The solid was separated from the solution using a frit on the vacuum line. The next day, the filtered crystals (0.325 g) were collected in the glove box. Yield = 87%, 38 including a trace of hexane. Trace amounts of hexane were removed on the vacuum line at -14°C (ice/methanol) for 3.5 h. Mp = 133-135°C. IR (Nujol mull) cm-1: 1298 (m),

1253 (s), 1238 (s), 1196 (s), 1175 (s), 1099 (w), 1025 (w), 948 (m), 854 (m), 798 (w),

766 (m), 761 (m), 722 (m), 688 (w), 627 (s), 617 (s), 538 (vs), 527 (vs), 484 (m) cm-1.

15 Anal. calcd. for [PCl2 N]3•AlCl3: P, 19.32%; Al, 5.61%; N, 9.30% and found P,

16.71%; Al, 7.67%; N 4.89%. Another test found P, 42.6% and Al, 18.3%. 31P NMR

15 27 (C6D6): δ 24.6 ppm (b, s), N NMR (C6D6): δ 97.3 ppm (m, unresolved), Al NMR

(C6D6): δ 107.1 ppm (b, s, FWHM = 682 Hz). For X-ray crystallographic information, see the Appendix.

15 Further characterization of [PCl2 N]3•AlCl3. Low temperature NMR studies

31 o were conducted on this adduct in toluene-d8. P NMR (ppm) 25 C: 24.8 (b,s), 21.2

(b,m); 0oC: 26.2 (b,s), 21.2 (b, m), 18.5 (sh), 17.5 (b,s); -20oC: 27.6 (b,s), 21.1 (b,m),

18.4 (sh), 17.4 (b, m); -40oC: 27.6 (b,s), 21.1 (b,m), 17.3 (b,m); -60oC: 27.2 (b,s), 21.0

(b,m), 17.0 (b,m). 27Al NMR (ppm) 25oC: 103.1 (b, s, FWHM = 792 Hz), 0oC: 103.4 (b, s, FWHM = 1223 Hz), -20oC: 104.8 (b, s, FWHM = 1913 Hz), -40oC: 105.3 (b, s,

FWHM = 2803 Hz), -60oC: ~111 (very broad, FWHM = 5073 Hz). 15N NMR (ppm)

-60oC: 95.7 (t), 83.8 (b, m), 77.8 (s).

15 Preparation of [PCl2 N]3•AlCl3 in CH2Cl2. In the glove box, a solution of

15 [PCl2 N]3 (0.400 g, 1.141 mmol) and 50 mL of CH2Cl2 was prepared. Purified AlCl3

(0.152 g, 1.141 mmol) was added and it quickly turned cloudy. The solution was swirled for 1 min. and allowed to stand. The flask was brought out of the glove box, and the solution appeared more transparent as the contents appeared to be partly soluble in the

CH2Cl2. This system was allowed to stand for 7 d on the lab shelf to yield a transparent 39 yellow solution. The flask was attached to the vacuum line and the solution was slowly concentrated by ~80% while submerged in a methanol/ice bath ~-18°C. The remaining

solution was allowed to stand for crystal growth, but no crystals formed overnight. The

remaining volatiles were removed at 0°C for 1 h on the vacuum line. Characterization

15 showed that this was the same adduct previously synthesize in hexane, [PCl2 N]3•AlCl3

15 15 (Yield ~85%), [PCl2 N]3 as the minor product, and a trace of [PCl2 N]4 (<1%).

Attempted syntheses of other adducts.

Other 1:1 reactions were conducted using similar procedures to those above.

Adduct formation was not observed for the following Lewis acids: InCl3, BiCl3, BBr3,

B(C6F5)3, WCl6, TaCl5, PCl5, BCl3, BF3•OEt2, and AgSO3CF3. The product was found to be the starting material, [PCl2N]3. In addition, a 1:3 trimer to AlBr3 reaction was conducted following the same procedure in order to synthesize a product having more than one acid bound to the trimer. This synthesis yielded the same 1:1 adduct,

15 [PCl2 N]3•AlBr3.

+- Another 1:1 reaction with Ag CB11H6Br6 did not result in the formation of an

15 adduct to [PCl2 N]3. A partial X-ray analysis showed that the product was the silver salt crystallized with toluene (solvent) molecules instead of reaction with [PCl2N]3.

Purification of InCl3. In the glove box, anhydrous white InCl3 (5 g in a sealed ampule) was put into a sublimator. The sublimation was conducted at 150oC overnight

(14 h) on the vacuum line. In the glove box, about 4 g of purified white InCl3 was collected.

Attempted syntheses of other adducts. In the glove box, a solution of

15 [PCl2 N]3 (0.401 g, 1.144 mmol) and 40 mL of hexane was prepared. InCl3 (0.253 g, 40 1.144 mmol) was added, but did not dissolve. The flask was allowed to stand for several

days and the acid did not dissolve. X-ray crystallography eliminated the possibility of adduct formation because the crystal volume was indicative of a small molecule such as

InCl3. Another attempt at this reaction in CH2Cl2 did not yield an adduct. No further characterization was done.

15 In the glove box, a solution of [PCl2 N]3 (0. 200 g, 0.570 mmol) and 30 mL of hexane was prepared. BiCl3 (0.179 g, 0.570 mmol) was added to give a clear solution with BiCl3 in the bottom. The flask was allowed to stir for 11 days in light. After filtration, a white powder (0.159 g) was collected. Yield: ~89%. Due to solubility issues, the 15N and 31P NMR spectrometry was unsuccessful in the attempt to characterize

o o the powder that appeared to be recovered BiCl3. Mp = 209 C (sublimes), 231 C

(decomposes).

15 In the glove box, a solution of [PCl2 N]3 (0. 400 g, 1.141 mmol) and 30 mL of hexane was prepared. BBr3 (107 µL, 1.132 mmol) was added slowly via syringe to give a solution with a slight cloudiness. This system was allowed to stand for 4 days to yield a transparent solution. After the solution was concentrated to ~90%, a crystalline white solid remained with thin colorless crystals along the walls of the flask. X-ray analyses on

15 two different crystals showed the product to be the starting material, [PCl2 N]3.

15 In the argon glove bag, a solution of [PCl2 N]3 (0. 400 g, 1.141 mmol) and CS2 was prepared. The dark purple solid, WCl6 (0.45g, 1.141 mmol), was added to give a dark purple solution that stained the Teflon valves dark orange. This system was allowed to stand for 7 days, but not crystals formed. After removing volatile materials on the

15 vacuum line, the major product was crystalline [PCl2 N]3, as determined by X-ray

41 crystallography. The minor product could not be characterized by crystallography or other techniques, but the unit cell was not the same as WCl6.

Syntheses of Protonated Species.

15 + - 15 Preparation of H[PCl2 N]3 SbCl6 . In the glove box, a solution of [PCl2 N]3

(0.200 g, 0.570 mmol) and 30 mL of hexane was prepared. SbCl5 (36 µL, 0.29 mmol) was added dropwise to give a light yellow transparent solution. The solution was taken out of the glove box and stirred for 1 h. Light tan crystals were evident in the bottom of the flask. The flask sat on the lab bench overnight and the crystals turned black while in the light.

The reaction was repeated in minimal light. In the glove box, a solution of

15 [PCl2 N]3 (0.200 g, 0.570 mmol) and 30 mL of hexane was prepared. SbCl5 (36 µL,

0.29 mmol) was added dropwise to give a light yellow transparent solution. The solution was allowed to stand for 8 days. Cream colored crystals were evident and the flask was taken into the glove box. X-ray crystallography was conducted on these crystals and the

15 + - structure was found to be the protonated species, H[PCl2 N]3 SbCl6 . In the glove box, a frit and receiving flask were attached to the flask containing the crystals. The crystals were filtered under vacuum via the Schlenk line and collected (0.100 g) in the glove box.

Yield ~99%. IR (Nujol mull cm-1): 1254 (m), 1191 (s), 1177 (s), 921 (m), 724 (w), 674

31 15 (m), 647 (m), 609 (m), 542 (m), 526 (m). P NMR (CD2Cl2): δ 19.2 ppm (m), N NMR

1 (CD2Cl2): δ 93.6 ppm (b, m), H NMR (CD2Cl2): δ 7.99 ppm (b,s). For X-ray crystallographic information, see the Appendix.

+ - Preparation of H[PCl2N]3 AlBr4 . Hexane was obtained from a

o sodium/benzophenone still. AlBr3 (Strem) was sublimed at 60 C under vacuum. The

42 sublimate was collected in air and stored in the glove box. In the glove box, a solution of

[PCl2N]3 (Aldrich, 0.174 g, 0.500 mmol) and 20 mL of hexane was prepared. AlBr3

(0.133 g, 0.500 mmol) was added to give a clear solution. The flask was covered with foil and allowed to stand in a lab drawer for 9 days. A white crystalline precipitate was observed and filtered under vacuum using the Schlenk line. Yield ~90%. 31P NMR

1 (CDCl3): δ 27.1 ppm (b,s), δ 16.9 ppm (b,s) H NMR (CDCl3): δ 10.14 ppm (b, s). For

X-ray crystallographic information, see the Appendix.

15 + - Alternative Preparation of H[PCl2 N]3 AlBr4 . In the glove box, a solution of

15 [PCl2 N]3 (0.400 g, 1.141 mmol) with 30 mL of hexane was prepared. AlBr3 (Aldrich, used as received, 0.304 g, 1.141 mmol) was added and it quickly turned cloudy. A crystalline precipitate was evident after 1 min. The solution was allowed to stand overnight and more crystalline precipitate had formed. These crystals were suitable for

15 X-ray diffraction and found to be the adduct, [PCl2 N]3•AlBr3.

The solution was opened in air in the hood. The crystalline precipitate was scraped from the sides of the flask and pushed back into the solvent. A septum was added to the top of the flask and distilled H2O (21 µL, 1.141 mmol) was added dropwise via syringe while the solution stirred. An aliquot of crystals were selected in air and found to be the adduct again. The flask was closed with a cap, kept under air, and allowed to stand. The solution was stored in the dark for several months to see if the addition of H2O would produce the protonated species over time. After 156 d, crystals

15 + were selected for X-ray analysis and found to be the protonated species, H[PCl2 N]3

- o 15 + - AlBr4 . Yield ~93%. Mp = 116-118 C. Anal. calcd. for H[PCl2 N]3 AlBr4 : P 13.3%,

Al 6.4%, H 0.14%, and found P 12.75%, Al 6.22%, H 0.43%. IR (Nujol mull cm-1):

43 3239 (s), 3072 (vs), 2393 (m), 1629 (m), 1303 (w), 1248 (m), 1195 (s), 1174 (s), 929 (m),

31 822 (m), 790 (m), 724 (w), 651 (m), 609 (s), 525 (s). P NMR (CD2Cl2): δ 19.5 ppm

3 1 1 (apparent d of t, JP-N = 11 Hz, JP-N = 16 Hz), δ -5.2 ppm (s), δ -12.0 ppm (b, s). H NMR

27 (CD2Cl2): δ 8.2 ppm (very broad). Al NMR (CD2Cl2): δ 87.2 ppm (b, s), δ 80.4 ppm

15 (b, s, FWHM = 69.5 Hz). N NMR (CD2Cl2): δ 109.3 ppm (s), δ 104.9 ppm (b, m), δ

95.7 ppm (m). For X-ray crystallographic information, see the Appendix.

15 + - Further characterization of H[PCl2 N]3 AlBr4 . Low temperature NMR

31 o studies were conducted on this species in CD2Cl2. P NMR (ppm) 25 C: δ 19.5

3 1 o (apparent d of t, JP-N = 11 Hz, JP-N = 16 Hz ), δ -5.2 (s), δ -12.0 (b, s), 0 C: δ 19.3

3 1 o (apparent d of t, JP-N = 11 Hz, JP-N = 16 Hz ), δ -4.8 (s), δ -11.3 (b, s), -20 C: δ 19.1

3 1 o (apparent d of t, JP-N = 12 Hz, JP-N = 15 Hz ), δ -4.4 (s), δ -10.7 (b, s), -40 C: δ 18.8

1 o (m, overlapped, JP-N = 15 Hz), δ -4.0 (s), δ -10.0 (b, s), -60 C: δ 18.7 (m, overlapped,

1 o 1 JP-N = 14 Hz), δ -3.6 (s), δ -9.3 (b, s), -80 C: δ 18.5 (m, overlapped, JP-N = 13 Hz), δ

27 14.1 (d, JP-N = 137 Hz) δ -3.2 (s), δ -8.4 (b, s), δ -13.9 (very broad). Al NMR (ppm)

25oC: δ 87.2 (b, s), δ 80.4 (b, s, FWHM = 69.5 Hz), 0oC: δ 87.4 (b, s), δ 80.7 (b, s,

FWHM = 83.7 Hz), -20oC: δ 87.5 (b, s), δ 80.6 (b, s, FWHM = 95.0 Hz), -40oC: δ 87.7

(very broad), δ 81.0 (b, s, FWHM = 111.0 Hz), -60oC: δ 87.9 (very broad), δ 81.2 (b, s,

FWHM = 134.0 Hz), -80oC: δ 88.0 (very broad), δ 81.4 (b, s, FWHM = 201.0 Hz). 1H

o o NMR (ppm) 25 C: δ 8.2 (very broad), -60 C: δ 8.2 (b, d JP-N = 80 Hz), δ 7.1 (b, s),

o 15 o -80 C: δ 8.2 (b, d, JP-N = 80 Hz), δ 7.1 (b, s). N NMR (ppm) -60 C: δ 108.5 ppm (b,m),

δ 102.7 ppm (b, m), δ 92.8 ppm (m).

15 + - 15 Preparation of H[PCl2 N]3 F3CSO3 . In a nitrogen glove bag, [PCl2 N]3

(0.0532 g, 0.1311 mmol) was added to an NMR tube. C6D6 was added to give a clear

44 solution. Triflic acid (~14 µL, 0.1311 mmol) was added via syringe and two layers were present. The NMR spectra were collected immediately and after spinning, one

31 homogeneous solution was observed in the NMR tube. P NMR (C6D6): δ 19.9 ppm

15 1 (m), N NMR (C6D6): 89.8 ppm (b, d), H NMR (C6D6): δ 12.80 ppm (b, s).

Attempts to Isolate Protonated Impurities in [PCl2N]3.

Characterization of (t-Bu)N-P(N(CH2)4)3, the P1-Phosphazene Base. In the glove box, a solution of the base in C6D6 was prepared in an NMR tube. The NMR tube

31 was not flame sealed and the data collection was done immediately. P NMR (C6D6,

13 1 ppm): δ -9.7 (s), C NMR (C6D6, ppm): 47.5 (d), 37.0 (d), 27.1 (d). H NMR (C6D6, ppm): δ 3.1 (p), δ 1.5 (q).

+ - Preparation of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ]. In the glove box, a solution of [PCl2N]3 (Aldrich, 0.261 g, 0.750 mmol) with 15 mL of hexane (dried over sodium/benzophenone ketyl) was prepared. (t-Bu)N-P(N(CH2)4)3 was added (25

µL, 0.800 mmol) to a beaker and a few drops of hexane was added. This solution was transfer via pipette to the bottom of a storage tube having a constriction half way up the length of the tube. More hexane was added to this solution and final volume was 1.6 mL.

The other solution containing trimer and hexane (2.8 mL) was added dropwise on top of the solution containing base. The storage tube was taken out of the glove box and stored at RT. After 11 days, no crystals had formed, so the tube was placed in a dewar filled with acetone and chilled to -35oC. After several months (141 d), tan crystals, suitable for

X-ray diffraction, were found to be the oxygenated trimer and protonated phosphazene

+ - 31 base, [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ]. Yield: 5%. P NMR (C6D6): δ 22.7

1 ppm (s), δ 20.9 ppm (d), δ -4.4 ppm (t). H NMR (C6D6): δ 7.76 ppm (d), δ 2.94 (p), δ

45 13 1.53 (t), δ 1.32 (s). C NMR (C6D6): δ 48.0 ppm (d), δ 32.0 (d), δ 26.6 (d). For X-ray crystallographic information, see the Appendix.

+ - Preparation of [(t-Bu)NH-P(N(CH2)4)3 ]Cl . In the nitrogen glove bag, a few drops of (t-Bu)N-P(N(CH2)4)3 was added to an NMR tube. Dry C6D6 (~1.5 mL) was added and HCl (g) was bubbled through the solution for 1 min. NMR spectra were collected immediately and no resonances for unreacted base (δ -9.8 ppm) were found.

The product was found to be the protonated phosphazene base, [(t-Bu)NH-

+ - 31 1 P(N(CH2)4)3 ]Cl . P NMR (C6D6): δ 22.7 ppm (s). H NMR (C6D6): δ 7.96 ppm (b, s).

+ - Another preparation of [(t-Bu)NH-P(N(CH2)4)3 ]Cl . In the glove box, a solution of [PCl2N]3 (Aldrich, 0.174 g, 0.500 mmol) and 20 mL of sym-tetrachloroethane was prepared and (t-Bu)N-P(N(CH2)4)3 (153 µL, 0.500 mmol) was added. A clear solution resulted. The flask was attached to a condenser with a bubbler and heated to

240-270oC for 1.5 h with 240oC being the optimal temperature. The solvent and other volatiles were removed under vacuum on the Schlenk line to give a mixture of crystals and a tan powder. The crystals were found to be [PCl2N]3 and the NMR spectra showed

+ - 31 the powder was [(t-Bu)NH-P(N(CH2)4)3 ]Cl . P NMR (C6D6): δ 22.8 ppm (s), δ 20.7 ppm (s). Other byproducts appear to be present because the 1H and 13C NMR spectra had

1 very complex patterns. H NMR (C6D6, ppm): δ 8.30 (b, m), δ 7.62 (m), δ 6.99 (m), δ

13 5.70 (s), δ 4.29 (m), δ 3.02 (m), δ 1.56 (m), δ 1.22 (m), δ 0.844 (m). C NMR (C6D6, ppm): δ 168.0 (s), δ 134.0 (s), δ 131.2 (s), δ 129.4 (s), δ 75.9 (s), δ 68.4 (s), δ 48.1 (d), δ

39.5 (s), δ 31.1 (s), δ 29.6 (s), δ 26.7 (s), δ 26.7 (s), δ 24.5 (s), δ 23.7 (s), δ 14.6 (s), δ 11.5

(s).

46 + - Isolation of (CH3CH2)3NH Cl During the Late Stages of the Synthesis of

[PCl2N]3. In the glove box, 25 mL of sym-tetrachloroethane was decanted into a Schlenk

flask. In air, NH4Cl (2.00 g, 36.7 mmol) and PCl5 (7.64 g, 36.7 mmol) were added to the

o solvent. The solution was heated to 210 C for 13 h and unreacted NH4Cl was filtered under vacuum through a frit on the Schlenk line. A 4 mL aliquot of the solution was decanted to another flask. Et3N (4 mL) was distilled from BaO into the flask on the vacuum line. After sitting overnight, a slushy crystalline solid remained. This material was allowed to stand. A thick crystalline material was filtered under vacuum through a frit. Crystals formed on the bottom of the flask were found to be the salt,

+ - 31 (CH3CH2)3NH Cl . Yield ~10%. P NMR spectroscopy showed that this mixture also contained ~22% [PCl2N]3 (s, δ 20.5 ppm), ~8% [PCl2N]4 (s, δ -6.0 ppm), ~6% [PCl2N]6

1 (s, δ -14.9 ppm), and ~64% [PCl2N]n (δ -17.6 ppm). H NMR spectra indicated a N-H bond at δ 11.9 ppm (b). Hexane (25 mL) was added to this solid and the solution was stirred for 2 days. A brown insoluble material, having similar appearance to the crosslinked polymer, was filtered from the solution and subject to vacuum for 3.5 h. 31P NMR spectra indicated that this material also contained polymer, but no cyclic species. The filtrate, a transparent yellow solution, was concentrated via the Schlenk line, and allowed to stand in the nitrogen bag. Crystals formed and x-ray analysis showed the crystals were

31 [PCl2N]3. P NMR spectra indicated that this material was a mixture of ~31% [PCl2N]3

(δ 20.5 ppm), ~11% [PCl2N]4 (δ -5.9 ppm), ~7% [PCl2N]6 (δ -14.9 ppm), and ~51%

[PCl2N]n (δ -17.6 ppm).

47 Synthesis of Poly(dichlorophosphazene), [PCl2N]n.

Melt Polymerization of [PCl2N]3. In the glove box, an NMR tube was filled with a mixture of dichlorophosphazenes ([PCl2N]3 = 95%, [PCl2N]4 = 5%; 0.050 g, 0.144 mmol of the mixture) and a selected catalyst (10% by mol). The tube was evacuated and flame sealed. The melt polymerizations were done by placing the NMR tube into a tube furnace heated to various temperatures. The tubes were taken into the nitrogen glove bag, opened, and deuterated solvent was added and they were capped. The amount of polymer synthesized was evaluated by NMR spectroscopy. The following chemical

31 shifts for the products are: P NMR (C6D6, ppm): [PCl2N]3 δ ~ 20.5 (s), [PCl2N]4 δ

~ -5.5 (s), [PCl2N]6 ~ -14.4 (b, s in some samples), [PCl2N]n δ ~ -17.0 ppm (b, s). There was a variety of catalysts used in these polymerizations. Following the procedure above,

o these other catalysts produced the polymer in low yield or not at all at 175 C: ZnCl2,

K2PtCl4, CH3SnCl3, (Ph)3CSnCl5, (Ph)3CBF4, Cp2TiCl2, and H2O.

48 References and Notes

1) Shriver, D. F.; Drexdon, M. A. The Manipulation of Air-Sensitive Compounds, 2nd ed.; Wiley: New York, 1986.

2) Plesch, P. H. High Vacuum Techniques for Chemical Syntheses and Measurements, Cambridge University Press: New York, 1989.

3) Sheldrick, G. M. SHELX97: Programs for Crystal Structural Analysis; University of Göttingen, Göttingen, Germany 1997.

4) Heston, A. J.; Tessier, C. A.; Panzner, M. J.; Youngs W. J. Phosphorus, Sulfur Silicon Relat. Elem., 2004, 179, 831-837.

49 CHAPTER III

RESULTS AND DISCUSSION

15 Synthesis and Characterization of Lewis and Brönsted Acid Adducts of [PCl2 N]3.

As described in the introduction, the nitrogen atoms of halide substituted phosphazenes are poor Brönsted-Lowery bases. There have been five complexes of

[PCl2N]3 with Lewis acids described: [PCl2N]3•AlBr3, [PCl2N]3•(AlCl3)2,

1,2 [PCl2N]3•(SO3)3, [PCl2N]3•SbCl5, and [PCl2N]3•WCl6. Only one complex of [PCl2N]3

3 with a Brönsted acid had been reported, that with HClO4. In all cases, these compounds were poorly characterized by modern standards and lacked x-ray crystallographic structure determinations. The synthesis and characterization of Lewis acid and Brönsted acid complexes of [PCl2N]3 are the subjects of this chapter. In order to obtain the most

15 complete NMR characterization, the N labeled [PCl2N]3 was used to prepare the complexes in most cases.

15 N Labeled [PCl2N]3

15 The synthesis of [PCl2 N]3 was conducted as described in literature with minor

15 15 modifications including the use of the labeled salt NH4Cl. [PCl2 N]3 purified via slow

15 sublimation in a long tube. The front and side views of the crystal structure of [PCl2 N]3

are shown in Fig. 3.1. The ring is often described as planar, but it was found to be a

50 slight chair structure. The deviation of P(1) and N(2) to a plane that includes the other four ring atoms, (N(1), N(1A), P(2), P(2A)), is described as the dihedral angles. The

15 Figure 3.1. Thermal ellipsoid plots for [PCl2 N]3. Front view(left), side view(right). 51 15 o o dihedral angles measured for [PCl2 N]3 were 9.7 (for N(2)) and 3.1 for (P(1)). The P-

N bonds in the ring range from 1.5795(16)-1.5822(17) Å for an average of 1.581 Å.

31 15 15 The P and N NMR spectra were obtained for [PCl2 N]3 (Fig. 3.2 and 3.3).

The 31P NMR spectrum provided a doublet of triplets at 20.6 ppm due to 15N-P coupling

3 1 15 with JP-N = 18 Hz and JP-N = 23 Hz. The N NMR spectrum showed an unresolved multiplet at 102.3 ppm. This pattern is due to an NMR phenomenon known as scalar relaxation of the second kind.4 Because nitrogen and chlorine have similar resonance frequencies, broadening of the central lines of the multiplet is observed.

21.2 20.8 20.4 20.0 ppm

31 15 Figure 3.2. P NMR spectrum of [PCl2 N]3 in C6D6.

108 106 104 102 100 98 ppm 15 15 Figure 3.3. N NMR spectrum of [PCl2 N]3 in C6D6.

52 Synthesis and characterization of Lewis Acid adducts of [PCl2N]3.

15 Equation 3.1 describes the reaction of [PCl2 N]3 with the Lewis acids AlBr3,

GaCl3, and AlCl3 to form the 1:1 adducts as colorless crystals having a melting point of

177-178°C, 130-133°C, and 133-135°C, respectively. Previously, CS2 had been used to prepare [PCl2N]3•AlBr3. The melting points of the [PCl2N]3•AlBr3 prepared by the two

5 methods are similar (174°C from CS2). All adducts have melting points that are different from that of their respective reagents. All adducts were highly air sensitive, so

rigorous anaerobic techniques were followed to prevent exposure to moisture.

X Cl Cl Cl Cl X P 15 M 15 15 15 P N N + MX3 NN X Cl Cl hexane P 15 Cl Cl P P 15 P Cl N Cl Cl N Cl

MX3=AlBr3, GaCl3, or AlCl3 (Eq. 3.1)

15 Crystals of [PCl2 N]3•AlBr3 suitable for single crystal x-ray diffraction studies were grown from a concentrated solution of dry hexane. The asymmetric unit contains

15 half of two [PCl2 N]3•AlBr3 adducts. There is an aluminum atom bound to one nitrogen

15 atom of [PCl2 N]3 as shown in Fig. 3.4. There are two Al-N bonds in the asymmetric unit at 1.994(4) Å (Al1-N1) and 1.987(4) Å (Al2-N3). The P-N bonds that flank the nitrogen atom bound to the aluminum (P1-N1 and P3-N3) show single bond character at

1.6580(19) and 1.6581(19) Å. The remaining P-N bonds range 1.578(3)-1.563(3) Å with

15 an average of 1.569 Å. The planarity of the [PCl2 N]3 ring has also been disturbed with

53 dihedral angles of 21.4°(P1-N1-P1A) and 13.6° (N2-P2-N2A) for one molecule and 19.5°

(P3-N3-P3A) and 11.5° (N4-P4-N4A) for the second.

15 Crystals of [PCl2 N]3•GaCl3 suitable for single crystal x-ray diffraction studies were also grown from a concentrated solution of dry hexane. The asymmetric unit

15 contains two [PCl2 N]3•GaCl3 molecules. A gallium atom is bound to one nitrogen atom

15 of each [PCl2 N]3 as shown in Fig. 3.4. There are Ga-N bonds in the asymmetric unit at

2.049(3) (Ga1-N1) and 2.048(3) Å (Ga2-N4). The P-N bonds that flank the nitrogen

bound to the gallium show single bond character at 1.644(3) (P1-N1), 1.640(3) (P2-N1),

1.641(3) (P4-N4), and 1.648(3) Å (P5-N4) with an average of 1.643 Å. The remaining P-

N-P bonds range from 1.578(3)-1.558(3) Å with an average of 1.569 Å. The planarity of

15 the [PCl2 N]3 ring has also been disturbed with dihedral angles of 20.6° (P1-N1-P2) and

7.8° (N2-P3-N3) for one molecule and 20.5° (P4-N4-P5) and 7.3° (N5-P5-N6) for the

second.

15 Crystals of [PCl2 N]3•AlCl3 suitable for single crystal x-ray diffraction studies were grown from a concentrated solution of dry hexane. The asymmetric unit contains

15 half of two [PCl2 N]3•AlCl3 molecules. There is an aluminum bound to one nitrogen

15 atom of each [PCl2 N]3 as shown in Fig. 3.4. There are two Al-N bonds in the asymmetric unit 1.977(5) (Al1-N1) Å and 1.978(5) Å (Al2-N3). The P-N bonds that flank the nitrogen bound to the aluminum show single bond character at 1.652(3) Å (P1-

N1) and 1.657(3) Å (P3-N3). The remaining P-N bonds range from 1.565(4)-1.572(4) Å

15 with an average of 1.569 Å. The planarity of the [PCl2 N]3 ring has also been disturbed with dihedral angles of 19.7° (P1-N1-P1A) and 11.7° (N2-P2-N2A) for one molecule and 17.7° (P3-N3-P3A) and 3.8° (N4-P4-N4A) for the second. 54 When comparing all three adducts, it is important to note that the two P-N bonds of the nitrogen atom bound to aluminum are weakened and longer than those P-N bonds

15 found in [PCl2 N]3, (Table 1). This feature may be significant to the first step in the

15 mechanism of ROP of [PCl2N]3. This ring distortion is more intense in [PCl2 N]3•AlBr3

15 15 15 than both [PCl2 N]3•GaCl3 and [PCl2 N]3•AlCl3, illustrating that [PCl2 N]3•AlBr3 is

15 the strongest adduct. The N→Al bond (1.99 Å, ave) of [PCl2 N]3•AlBr3 and (2.11 Å,

15 ave) of [PCl2 N]3•AlCl3 are comparable to that in a tetramethylpiperidine adduct,

15 (tmpH•AlBr3), (2.01 Å, ave). Both the N→Ga bond (2.05 Å, ave) of [PCl2 N]3•GaCl3

15 and the N→Al bond (2.11 Å, ave) of [PCl2 N]3•AlCl3 and is comparable to that in the carbophosphazene, [(PCl2N)(CPhN)-(PCl(NPCl3)N)], (2.00 Å , ave). As expected from the difference in covalent radii of the group 13 atoms, the Al-N bonds (1.977(5) and

1.978(5) Å) are shorter than the Ga-N bonds (2.049(3) and 2.048(3) Å). The distances between the group 13 and the nitrogen atoms are in the range of dative bonds (M = Al,

6 7,8 1.94-2.10 Å ; M = Ga, 1.95-2.20 Å ). When compared to distances in other MCl3

15 adducts of nitrogen-containing bases, the M-N bonds of both [PCl2 N]3●MCl3 (M = Al,

Ga) are relatively long. From this data, the N→M bond length increases as the interaction between the nitrogen and metal weakens, illustrating the weakest adduct of

15 the group is [PCl2 N]3•GaCl3.

31 15 15 The P NMR spectra (Fig. 3.5) for [PCl2 N]3•AlBr3, [PCl2 N]3•AlCl3, and

15 o [PCl2 N]3•GaCl3 were collected in C6D6 at 25 C for all three adducts and compared to

15 31 15 [PCl2 N]3. The P NMR spectrum for [PCl2 N]3•AlBr3 showed two broad singlets 27.1

31 15 ppm and 16.8 ppm. P NMR spectrum for [PCl2 N]3•GaCl3 showed a broad signal at

55 23.4 ppm, having a broad shoulder at 23.3 ppm. The spectra from the adducts differ from

15 31 the starting material [PCl2 N]3 because the P NMR spectrum showed a doublet of triplets 20.6 ppm. Because the 31P NMR spectrum shows a broad signal compared to two

15 distinct peaks found for [PCl2 N]3•AlBr3, an exchange must be occurring between

15 gallium and the nitrogen atom of [PCl2 N]3. This supports the x-ray crystallography in that there is a tighter interaction between for Al to N than Ga to N.

31 15 The P NMR spectrum (Fig. 3.5) for [PCl2 N]3•AlCl3 showed a broad singlet

31 15 24.6 ppm. The P NMR spectrum for [PCl2 N]3•GaCl3 showed a broad signal at 23.4 ppm, having a broad shoulder at 23.3 ppm. The spectra from the adducts differ from the

15 31 starting material [PCl2 N]3 because the P NMR spectrum showed a doublet of triplets at 20.6 ppm. Because the 31P NMR spectra show broad singlets, an exchange must be

15 15 occurring between both metals and the N of [PCl2 N]3 in the solution phase.

15 15 15 The N NMR spectra of [PCl2 N]3•AlBr3, [PCl2 N]3•GaCl3, and

15 o 15 [PCl2 N]3•AlCl3 (Fig. 3.6) were collected in C6D6 at 25 C. The N NMR spectrum for

15 the adducts showed complex multiplets: [PCl2 N]3•AlBr3 at 93.3 ppm,

15 15 [PCl2 N]3•AlCl3 at 97.3 ppm, and [PCl2 N]3•GaCl3 at 95.9 ppm. All multiplets are due to P-15N couplings. The 15N NMR spectra for all adducts were similar, showing upfield

15 shifts 5-7 ppm from the [PCl2 N]3.

27 15 15 The Al NMR spectra for [PCl2 N]3•AlBr3 and [PCl2 N]3•AlCl3 (Fig. 3.7) in

o 27 C6D6 were collected 25 C and compared to AlBr3 and AlCl3 starting materials. The Al

NMR spectrum showed a broad singlet 94.0 ppm with a ∆1/2 = 423 Hz which was

27 different from AlBr3 (80.2 ppm). The Al NMR spectrum showed a broad singlet 107.1

15 15 Figure 3.4. Thermal ellipsoid plots of [PCl2 N]3•AlBr3 (left), [PCl2 N]3•AlCl3 (bottom), and

15 [PCl2 N]3•GaCl3 (right). 57

15 15 Table 3.1. Bond lengths and bond angles for [PCl2 N]3•AlCl3, [PCl2 N]3•AlBr3, 15 15 [PCl2 N]3•GaCl3, and [PCl2 N]3.

AlCl3 adduct AlBr3 adduct GaCl3 adduct Ring Al-N (Å) ESD Al-N (Å) ESD Ga-N (Å) ESD 1.977 5 1.994 4 2.049 3 1.978 5 1.987 4 2.048 3 Ave 1.978 Ave 1.991 Ave 2.049 P---N (Å) P---N (Å) P---N (Å) 1.652 3 1.6580 19 1.640 3 1.657 3 1.6581 19 1.644 3 1.652 3 1.6580 19 1.648 3 1.657 3 1.6581 19 1.641 3 Ave 1.655 Ave 1.6581 Ave 1.643 P-N (Å) P-N (Å) ESD P-N (Å) ESD P-N (Å) ESD 1.567 4 1.574 3 1.577 3 1.5821 17 1.569 4 1.574 3 1.574 3 1.5822 17 1.569 4 1.563 3 1.566 3 1.5795 16 1.565 4 1.578 3 1.558 3 1.5810 13 1.572 4 1.564 3 1.565 3 1.5810 13 1.572 4 1.578 3 1.576 3 1.578 3 1.563 3 Ave 1.569 Ave 1.572 Ave 1.570 Ave 1.581 Dihedral at N (o) Dihedral at N (o) Dihedral at N (o) Dihedral at N (o) 19.7 21.4 20.6 17.7 19.5 20.5 9.7 Dihedral at P (o) Dihedral at P (o) Dihedral at P (o) Dihedral at P (o) 11.7 13.6 7.8 3.8 11.5 7.3 3.1

35 25 15 5 ppm c a d b

31 15 15 Figure 3.5. P NMR spectra of [PCl2 N]3 (a), [PCl2 N]3•GaCl3 (b),

15 15 o [PCl2 N]3•AlCl3 (c), and [PCl2 N]3•AlBr3 (d) in C6D6 at 25 C.

ppm 85 90 95 100 105 110 115 120 d c b a

15 15 15 Figure 3.6. N NMR spectra of [PCl2 N]3 (a), [PCl2 N]3•GaCl3 (b),

15 15 o [PCl2 N]3•AlCl3 (c), and [PCl2 N]3•AlBr3 (d) in C6D6 at 25 C.

60 ppm 50 60 70 80 90 100 110 120 130 140 150 b a 160

27 15 15 Figure 3.7. Al NMR spectra of [PCl2 N]3•AlCl3 (a)and [PCl2 N]3•AlBr3 (b)

o in C6D6 at 25 C. 61 ppm with ∆1/2 = 681.7 Hz which is different from AlCl3 (100.0 ppm). The room

15 temperature NMR spectra in C6D6 for the three [PCl2 N]3•MX3 (M = AlBr3, AlCl3,

GaCl3) were consistent with fluxional behavior. Presumably, the adducts dissociate in

solution. The room temperature spectra suggested that the AlBr3 adduct was the least dissociated. In order to fully understand the fluxionality, the variable temperature NMR

31 spectra of the adducts were obtained in toluene-d8. The P NMR spectra were collected

15 o o o for [PCl2 N]3•AlBr3 in CD2Cl2 from 25 C to -60 C as shown in Fig. 3.8. At 25 C, there were two broad resonances 27.2 ppm and 17.6 ppm. These resonances sharpened when the temperature was decreased to 0oC. A new broad resonance at 19.7 ppm was also observed at this temperature. As the temperature was decreased, complex coupling patterns were observed. At temperatures below -60oC, the couplings were not observed

15 due to an increase in the viscosity of the toluene-d8 solution. The N NMR spectrum in

o o CD2Cl2 at 25 C provided a broad multiplet at 93.3 ppm. At -60 C in CD2Cl2, the

1 2 spectrum showed a doublet of triplets ( JP-N = 18.6 Hz, JP-P = 10.4 Hz) at 94.7 ppm as shown in the stack plot of Fig. 3.9.

31 15 The P NMR spectra were collected for [PCl2 N]3•AlCl3 in toluene-d8 from

25oC to -60oC as shown in Fig. 3.10. At 25oC, there was a single broad resonance at 24.8

15 ppm with a small broad resonance at ~21 ppm. Like [PCl2 N]3•AlBr3, these resonances were found to sharpen when the temperature was lowered to 0oC. A new broad resonance at 17.5 ppm was also observed along with a multiplet at 21.2 ppm at this temperature. As the temperature was decreased, complex coupling patterns began to

15 appear. Unlike [PCl2 N]3•AlBr3, the coupling patterns were only observed for one of

62 the resonances (17.0 ppm at -60oC), not both. The other resonance remained broad. The

15 o N NMR spectrum in toluene-d8 at 25 C provided an unresolved multiplet at 97.3 ppm.

At -60oC, three resonances were observed including a triplet 95.7 ppm, a broad

multiplet at 83.8 ppm, and a broad singlet at 77.8 ppm as shown in Fig. 3.9. The 27Al

NMR spectrum in C6D6 provided a single broad resonance at 103.1 ppm with ∆1/2 = 682

27 Hz. By conducting a variable temperature Al NMR experiment in toluene-d8, it was found that this resonance became broader as the temperature was decreased. A very

o broad resonance was observed at -60 C and the ∆υ1/2 increased to 5073 Hz. This observation follows the prediction that as the temperature decreases, the Al signal becomes broader due to that fact that the Al is more strongly bound to the N atom of

15 [PCl2 N]3 and, thereby the symmetry at the aluminum atom is lowered.

31 15 o The P NMR spectra was collected for [PCl2 N]3•GaCl3 in toluene-d8 from 25 C to -60oC as shown in Fig. 3.11. The spectrum collected at 25oC was similar to that for

15 [PCl2 N]3•AlCl3 because it showed a single broad resonance at 22.6 ppm. This

resonance became broader at 0oC and -20oC. At -40oC, this resonance split into two overlapping resonances at 25.5 ppm and 18.4 ppm. In addition, there was a new resonance at 22.0 ppm. As the temperature was decreased to -60oC, the resonances became more pronounced (26.2 ppm, 19.8 ppm, 16.6 ppm). The resonance at 19.8 ppm is proposed as free trimer as the GaCl3 migrates between the rings in solution as shown in the equation in Fig. 3.11. The experiment was also conducted at -70oC to see if coupling patterns could be observed. At this temperature, each resonance sharpened, but no

15 o coupling patterns were evident. The N NMR spectrum in toluene-d8 at 25 C provided

ppm

0ºC 34 25ºC -60ºC -40ºC -20ºC

31 15 Figure 3.8. Variable temperature P NMR spectra of [PCl2 N]3•AlBr3 in CD2Cl2.

ppm

100

105

110

c b 115

15 15 15 Figure 3.9. N NMR spectra of [PCl2 N]3•GaCl3 (a), [PCl2 N]3•AlCl3 (b) in

15 o toluene-d8, and [PCl2 N]3•AlBr3 (c) in CD2Cl2 at -60 C. 65

ppm

40 C C C C

o o o o C o 0 25 -20 -60 -40

31 15 Figure 3.10. Variable temperature P NMR spectra of [PCl2 N]3•AlCl3 in toluene-d8.

Cl Cl Cl Cl Ga Cl Cl 15 15 15 P 15 P NN Cl NN+ GaCl3 Cl Cl Cl Cl P 15 P P 15 P Cl N Cl Cl N Cl

-60oC

-40oC

-20oC

o 0 C

25oC

34 32 30 28 26 24 22 20 18 16 14 12 10 8 ppm

31 15 Figure 3.11. Variable temperature P NMR spectra of [PCl2 N]3•GaCl3 in toluene-d8.

67 an unresolved multiplet at 95.9 ppm. At -60oC, three resonances were observed including two broad multiplets at 96.4 ppm and 84.2 ppm.

15 The variable temperature NMR studies suggest that [PCl2 N]3GaCl3 is not as

15 15 tightly bound as [PCl2 N]3•AlBr3 or [PCl2 N]3•AlCl3. From the NMR spectroscopy, it

15 appears that [PCl2 N]3•AlBr3 is the most tightly bound adduct due to the coupling that was observed in the 31P NMR spectra compared to the other adducts which observed

partial or no coupling at low temperatures (Fig. 3.12). The unresolved multiplets for each

adduct become more pronounced when the 15N nuclei is observed at lower temperatures

(Fig. 3.9).

Multidimensional NMR studies were conducted to resolve the complex coupling

15 o pattern observed for [PCl2 N]3•AlBr3 at -60 C. A Homo2DJ experiment was conducted at -60oC to resolve these coupling patterns and the coupling constants were found. This temperature was chosen based on the spectra in Fig. 3.8. For the resonance at 16.5 ppm,

1 2 there was one JP-N coupling (19.5 Hz) and one J P-P coupling (44.5 Hz) as shown in Fig.

1 3.13. For the resonance at 26.2 ppm, there were two JP-N couplings (22.5 Hz, 25.7 Hz)

2 and two JP-P couplings (8.5 Hz, 44.5 Hz) as shown in Fig. 3.14. The coupling constants

3 are assigned to the resonances as shown in Figure 3.15. No JP-N couplings were observed in the Homo2DJ experiment. A proposed explanation is that the coupling is not observed due to the distortion of the ring and, therefore, these atoms do not couple to each other in this orientation.

From the VT NMR spectroscopy, 15N-31P couplings could only be observed for

15 o [PCl2 N]3•AlBr3 at -60 C. By incorporating the Homo2DJ experiment, the coupling constants could be measured, resolving the complex multiplets. The NMR spectral data 68

ppm 14 18 22 26 c a b

31 15 15 Figure 3.12. P NMR spectra of [PCl2 N]3•GaCl3 (a), [PCl2 N]3•AlCl3 (b) in toluene-

15 o d8, and [PCl2 N]3•AlBr3 (c) in CD2Cl2 at -60 C.

17.0 16.9 16.8 16.7 16.6 16.5 16.4 16.3 16.2 ppm

F2 (ppm)

16.35 2 44.5Hz( JP-P )

16.40

16.45

16.50

1 16.55 19.5Hz( JP-N )

16.60

16.65

16.70

100 90 80 70 60 50 40 30 20 10 0

F1 (Hz)

Figure 3.13. The expanded triplet of triplets at 16.5 ppm in the 31P NMR

15 spectrum (top). The Homo2DJ NMR spectrum of [PCl2 N]3•AlBr3 (bottom) in CD2Cl2.

(F1 axis: 31P-31P homonuclear coupling, F2 axis: 31P-15N heteronuclear coupling)

70 26.6 26.5 26.4 26.3 26.2 26.1 26.0 25.9 25.8 ppm

8.5Hz

44.5 Hz (2J ) P-P

F2 (ppm) 25.7

25.8

25.9

26.0

22.5Hz 26.1 25.7Hz

26.2

26.3

26.4

26.5

90 80 70 60 50 40 30 20 10 F1 (Hz)

Figure 3.14. The expanded octet of doublets at 26.2 ppm of the 31P NMR spectrum

15 (top). The Homo2DJ NMR spectrum of [PCl2 N]3•AlBr3 (bottom) in CD2Cl2. (F1 axis:

31P-31P homonuclear coupling, F2 axis: 31P-15N heteronuclear coupling)

71 2’

44.5Hz 3’ 2’’ 1’ 3 3’’ 1 1’’

19Hz

17.0 16.9 16.8 16.7 16.6 16.5 16.4 16.3 16.2 ppm

44.5 Hz

21.5 Hz

17.5 Hz

8.5 Hz

26.5 26.4 26.3 26.2 26.1 26.0 ppm

Figure 3.15. Detailed assignment of the 31P-15N couplings from the Homo2DJ

15 NMR spectra of [PCl2 N]3•AlBr3 in CD2Cl2.

72 15 are in agreement with the x-ray analysis that [PCl2 N]3•AlBr3 has the most tightly bound

15 metal to [PCl2 N]3.

15 15 The IR spectra (Nujol mull) were collected for [PCl2 N]3, [PCl2 N]3•AlBr3,

15 15 [PCl2 N]3•AlCl3 and [PCl2 N]3•GaCl3. In comparison, the spectra for all three adducts

15 showed similarities to [PCl2 N]3 by the presence of P=N bonds. These bands were in the range 1300-1200 cm-1 representing the P=N bonds of dichlorophosphazenes.9 The bands in the range 587-420 cm-1, found for all three adducts, indicates the presence of P-Cl

15 bonds. These bands are similar to those found in the spectrum for [PCl2 N]3. In

15 15 contrast, only [PCl2 N]3•AlBr3 and [PCl2 N]3•AlCl3 had bands in the range 1055-870 cm-1, indicating the presence of P-N bonds.

Other 1:1 reactions between [PCl2N]3 and various Lewis acids were conducted using similar procedures to those described above. Adduct formation was not observed for the following Lewis acids: InCl3, BiCl3, BBr3, B(C6F5)3, WCl6, TaCl5, PCl5, BCl3,

BF3•OEt2, and AgSO3CF3. The product was found to be the starting material, [PCl2N]3.

15 In addition, a 1:3 [PCl2 N]3 to AlBr3 reaction was conducted following the same procedure in order to synthesize a product having more than one AlBr3 bound to the

15 trimer. This synthesis yielded the same 1:1 adduct, [PCl2 N]3•AlBr3. A 1:1 reaction

+- with Ag CB11H6Br6 in toluene did not result in the formation of an adduct to [PCl2N]3.

A partial x-ray analysis showed that the product was the silver salt crystallized with toluene (solvent) molecules. This suggests that toluene is a better base to the silver cation than [PCl2N]3.

73 Synthesis and Characterization of Brönsted Acid Adducts of [PCl2N]3.

15 + - + - The syntheses of the protonated species, H[PCl2 N]3 SbCl6 , H[PCl2N]3 AlBr4 ,

15 + - and H[PCl2 N]3 AlBr4 were conducted under less rigorous anaerobic conditions, which allowed Brönsted acid reactions to occur. Equation 3.2 describes the reaction of

15 [PCl2 N]3 with the Lewis acids SbCl5 and AlBr3 in the presence of protonic impurities.

For these reactions, SbCl5 and AlBr3 were purified under less rigorous anaerobic techniques and may have contained hydrogen-bonded HCl and HBr impurities. The

Cl Cl Cl Cl P + 15 15 15 H 15 P H MXm N N + MXn NN Cl Cl hexane P 15 P Cl Cl Cl N P 15 P Cl Cl N Cl (Eq. 3.2) - - - MXn = AlBr3 or SbCl5 MXm = AlBr4 or SbCl6

10,11 formation of these impurities is shown in Eq. 3.3. SbCl5 was difficult to handle due to its corrosive nature, limiting purification to a certain degree. It was proposed that the purification via vacuum apparently did not remove all protonated impurities in SbCl5. In addition, its sensitivity to light also created challenges in this synthesis.

MXn + H2O HX + X2MOH (Eq. 3.3)

MXn + HX H MX4

MXn = AlBr3 or SbCl5 H MX4 = HAlBr4 or HSbCl6

74 15 + - Colorless crystals of H[PCl2 N]3 SbCl6 Fig. 3.16 suitable for single crystal x-ray

diffraction studies were grown from a concentrated solution of dry hexane. The

15 + - asymmetric unit contains one H[PCl2 N]3 SbCl6 as shown in Fig. 3.16. The hydrogen atom could not be isolated. However, one N---Cl distance of 3.27Å is consistent with a

N-H---Cl hydrogen bond. The P-N bonds associated with nitrogen bound to the H+ show single bond character 1.656(5) (P1-N1) and 1.664(5) Å (P2-N1) with an average of

1.660 Å. The remaining P-N bonds range from 1.592(5)-1.540(5) Å with an average of

1.567 Å.

+ - 15 + - Colorless crystals of H[PCl2N]3 AlBr4 or H[PCl2 N]3 AlBr4 suitable for single crystal x-ray diffraction studies were grown from a concentrated solution of dry hexane.

+ - The asymmetric unit contains one H[PCl2N]3 AlBr4 as shown in Fig. 3.16. The hydrogen atom could not be isolated. However, one N---Br distance of 3.36 Å is consistent with a N-H---Br hydrogen bond. The P-N bonds associated with the nitrogen bound to the H+ show single bond character 1.663(5) (P1-N2) and 1.664(5) Å (P2-N2) with an average of 1.664 Å. The remaining P-N bonds range from 1.553(5)-1.590(5) Å with an average of 1.571 Å. The structure of the labeled compound is identical, within experimental error, with that described for the unlabeled compound above. The hydrogen atom also could not be located. However, one N---Br distance of 3.36 Å is consistent with a N-H---Br hydrogen bond. The P-N bonds associated with the nitrogen bound to the H+ show single bond character 1.665(3) (P1-N1), 1.661(4) Å (P2-N1) with an average

of 1.663 Å. The remaining P-N bonds range from 1.554(3)-1.583(3) Å with an average

of 1.568 Å.

75 15 + - 15 + - Figure 3.16. Thermal ellipsoid plots of H[PCl2 N]3 SbCl6 and H[PCl2 N]3 AlBr4 .

76 31 15 + - The P NMR spectrum (Fig. 3.17) for H[PCl2 N]3 SbCl6 in CD2Cl2 showed a

15 multiplet at 19.2 ppm and the N NMR spectrum (Fig 3.18) in CD2Cl2 showed a broad

15 1 multiplet at 93.6 ppm, due to P- N couplings. The H NMR spectrum in CD2Cl2 provided evidence for the N-H bond by a broad singlet at 7.99 ppm.

31 + - The P NMR spectrum for H[PCl2N]3 AlBr4 in CDCl3 showed two broad resonances at 27.1 ppm and 16.9 ppm at almost identical chemical shifts to those of

15 1 [PCl2 N]3•AlBr3. The H NMR spectrum in CDCl3 showed the N-H bond of this species by a broad resonance at 10.14 ppm.

31 15 + - The P NMR spectrum of H[PCl2 N]3 AlBr4 in CD2Cl2 showed an apparent

3 1 doublet of triplets at 19.5 ppm with JP-N = 11 Hz and JP-N = 16 Hz as shown in Fig. 3.17.

Trace amounts of larger rings were evident by a singlet at -5.2 ppm and a broad singlet at

-12.0 ppm. The 1H NMR spectrum showed a broad resonance at 8.2 ppm. The 27Al

NMR spectrum showed two broad singlets at 87.2 ppm and 80.4 ppm. The 15N NMR showed a singlet at 109.3 ppm and two multiplets 104.9 ppm and 95.7 ppm as shown in

Fig. 3.18.

The variable temperature NMR spectroscopy was conducted on

15 + - 31 o o H[PCl2 N]3 AlBr4 in CD2Cl2. The P NMR spectra were collected from 25 C to -60 C as shown in Figure 3.19 and Fig. 3.20. At 25oC, there was an apparent doublet of triplets

15 at 19.5 ppm and trace impurities showed singlets for [PCl2 N]4 at -5.2 ppm and

15 [PCl2 N]5 at -12.0 ppm. These resonances were found to sharpen when the temperature was decreased to 0oC and they progressively sharpened at -20oC, -40oC, and -60oC. At

-40oC, the apparent doublet of triplets coupling pattern could no longer be observed, so

3 o JP-N couplings could not be calculated below -20 C. The other resonances remained as

ppm

c b a

31 15 15 + - Figure 3.17. P NMR spectra of [PCl2 N]3 (a) in C6D6, H[PCl2 N]3 SbCl6 (b),

15 + - o and H[PCl2 N]3 AlBr4 (c) in CD2Cl2 at 25 C.

ppm

100

102

104

106

108

110

112

114

116 118 c b a

15 15 15 + - Figure 3.18. N NMR spectra of [PCl2 N]3 (a) in C6D6, H[PCl2 N]3 SbCl6 (b),

15 + - o and H[PCl2 N]3 AlBr4 (c) in CD2Cl2 at 25 C.

ppm

-10

-5

0ºC 25ºC - 20ºC -60ºC -40ºC

31 15 + - Figure 3.19. Variable temperature P NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2.

ppm

0ºC 25ºC - 60ºC - 40ºC - 20ºC

Figure 3.20. Expanded view of the variable temperature 31P NMR spectra of

15 + - H[PCl2 N]3 AlBr4 in CD2Cl2.

81 singlets at these lower temperatures, but the resonance at -9.3 ppm became broad at

-60oC. Measuring coupling constants at lower temperature such as -80oC was not possible due to the line broadening at temperatures below -60oC as observed for the adducts. This can be due to an increase in the viscosity of the CD2Cl2 solution.

However, the spectrum was collected at -80oC and showed a new resonance, a doublet at

15 14.1 ppm (JP-N = 137 Hz) and a very broad signal begins to show at -13.9 ppm. The N

NMR spectrum at 25oC provided a broad singlet at 109.3 ppm and two broad multiplets, at 104.9 ppm (minor) and at 95.7 ppm (major) as shown in Fig. 3.21. At -60oC, the spectrum showed two minor broad multiplets at 108.5 ppm and 102.7 ppm and the major broad multiplet at 92.8 ppm. The 27Al NMR spectrum at 25oC gave a broad singlet with and the major was a broad singlet at 80.4 ppm with ∆1/2 = 69.5 Hz. The minor broad singlet at 87.2 ppm was proposed as an effect from the solvent.12 A variable temperature

27Al NMR experiment showed that this resonance became broader as the temperature was

o decreased as shown in Fig. 3.22. A very broad resonance was observed at -80 C and ∆1/2

increased from 69.5 Hz at room temperature to 201.0 Hz. This observation follows the

prediction that as the temperature decreases, the 27Al signal becomes broader due to its interaction with the ring though the N-H---Br bond. At very low temperatures, exchange would be slower or nonexistent. In addition, the minor singlet was barely evident at

-80oC due to the solvent’s increased viscosity. The 1H NMR spectrum at 25oC did not show a clear N-H bond, but a broad signal under the solvent peak at ~5.2 ppm. At -60oC, a broad doublet was observed at 8.3 ppm. This showed that at 25oC, the exchange between N and H was very fast, but slowed enough to be observed at -60oC. At -80oC, the doublet was broader, but still evident.

ppm 92

100

102

104

106

108

110

112

25ºC 114

- 60ºC

15 15 + - Figure 3.21. Variable temperature N NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2.

ppm

92 C C C o o o 25 -20 -60 94

27 15 + - Figure 3.22. Variable temperature Al NMR spectra of H[PCl2 N]3 AlBr4 in CD2Cl2.

84 From the variable temperature 31P NMR studies, it was concluded that the proton

15 + - 31 in H[PCl2 N]3 AlBr4 was exchanging very fast. The P NMR spectrum of

15 + - 15 H[PCl2 N]3 AlBr4 is very similar to that for [PCl2 N]3. From all the NMR studies,

15 interaction of [PCl2 N]3 can be put into the following order of decreasing strength:

+ 31 o AlBr3 > AlCl3 > GaCl3 > H . When comparing the P NMR spectra at 25 C, the

15 + - multiplet found for H[PCl2 N]3 AlBr4 versus the two broad singlets found for

15 [PCl2 N]3•AlBr3 clearly shows that the proton is exchanging much faster in the

15 protonated species than the adduct as shown in Fig. 3.23. Therefore, [PCl2 N]3 must be

15 + - 15 bound more tightly in the adduct than in H[PCl2 N]3 AlBr4 . The N NMR spectra for

15 + - 15 H[PCl2 N]3 AlBr4 and [PCl2 N]3•AlBr3 have resonances at similar chemical shifts, but the coupling patterns are different (Fig. 3.24). In contrast, the 31P NMR spectra shows a

15 + - 15 doublet of triplets for H[PCl2 N]3 AlBr4 , but the resonance for [PCl2 N]3•AlBr3 is broad. This supports the observation that AlBr3 undergoes some exchange around the

ring, but not nearly as fast as H+. When comparing the 27Al NMR spectra as shown in

Fig. 3.25, both have broad signals. The line width at half height is much smaller for

15 + - 15 H[PCl2 N]3 AlBr4 at 69.5 Hz than [PCl2 N]3•AlBr3 at 423 Hz. The narrow peak width is consistent with the expectation that the aluminum is in a more symmetrical orientation

15 + - 15 in H[PCl2 N]3 AlBr4 than in [PCl2 N]3•AlBr3.

From the low temperature 15N NMR spectra, the H+ appears to be bound more

15 + - 15 + - tightly to H[PCl2 N]3 AlBr4 than H[PCl2 N]3 SbCl6 . The spectra show that the exchange is very fast because the 15N spectrum provided a multiplet for

15 + - 15 H[PCl2 N]3 AlBr4 which is highly similar to that for [PCl2 N]3. Both species in solution appear to behave as the unreacted starting material, but both have a chemical 85

34 32 30 28 26 24 22 20 18 16 14 12 ppm

31 15 + - 15 Figure 3.23. P NMR spectra of H[PCl2 N]3 AlBr4 (top) in and [PCl2 N]3•AlBr3

o (bottom) in CD2Cl2 at 25 C.

ppm

100

105

110

115

120

31 15 + - 15 Figure 3.24. P NMR spectra of H[PCl2 N]3 AlBr4 (top) and [PCl2 N]3•AlBr3

o (bottom) in CD2Cl2 at 25 C.

105 100 95 90 85 80 75 ppm

27 15 + - 15 Figure 3.25. Al spectra of of H[PCl2 N]3 AlBr4 (top) and [PCl2 N]3•AlBr3 (bottom)

o in CD2Cl2 at 25 C.

88 shift downfield of ~1 ppm from the ring in the 31P NMR spectra. Both species have

broad resonances in the 1H NMR spectra near 8 ppm at 25oC. As the temperature was

o 15 + - lowered to -60 C, the broad resonance at 8.3 ppm for H[PCl2 N]3 AlBr4 was more pronounced, again indicating this N-H interaction is exchanging faster than in

15 + - H[PCl2 N]3 SbCl6 .

15 + - Multidimensional NMR spectroscopy was conducted on H[PCl2 N]3 AlBr4 . A

31P/15N Heteronuclear Multiple Quantum Correlation (HMQC) experiment was

15 + - o completed for H[PCl2 N]3 AlBr4 in CD2Cl2 at 25 C as shown in Fig. 3.26. The 2D spectra correlate the phosphorus and nitrogen chemical shifts so that assignments can be made. The correlation of chemical shift to the compounds present in solution were

15 + - 31 15 15 31 assigned H[PCl2 N]3 AlBr4 P at 19.6 ppm and N 95.7 ppm (a), [PCl2 N]4 P at -5.4

15 15 31 15 ppm and N 109.5 ppm (b), [PCl2 N]5 P at -12.5 ppm and N 104.7 ppm (c). Now the chemical shifts for both nuclei can be used to identify all three compounds.

15 Because the nitrogen atom of [PCl2 N]3 is weakly basic, an NMR tube reaction was done to observe its reactivity with a commercial super acid. A 1:1 reaction with triflic acid in C6D6 was examined as shown in Eq. 3.4. The acid protonated the nitrogen

15 atom of [PCl2 N]3 to give a new N-H bond. A new resonance was observed as a broad

singlet at 12.80 ppm in the 1H NMR spectrum, which was different than that for triflic

acid at 11.14 ppm. The 31P NMR spectrum showed a multiplet at 19.9 ppm and the 15N

NMR spectrum provided a broad overlapping doublet at 89.8 ppm (Fig. 3.27). Both of these patterns are due to P-15N coupling. Cl Cl Cl Cl 15 P 15 15 P H + F CSO H N N 3 3 N N15 + F3CSO3 Cl Cl C6D6 Cl Cl P 15 P P 15 P (Eq. 3.4) Cl N Cl Cl N Cl 89

F2 (ppm) a 19.45

19.50

19.55

19.60

19.65

19.70

19.75 98.0 97.5 97.0 96.5 96.0 95.5 95.0 94.5 94.0 93.5 93.0 F1 (ppm)

F2 F2 (ppm) (ppm) -5.47 bc -5.46 -12.54

-5.45 -12.53 -5.44 -5.43 -12.52

-5.42 -12.51 -5.41 -5.40 -12.50

-5.39 -12.49 -5.38

-5.37 -12.48

-5.36 -12.47 -5.35

105.2 105.0 104.8 104.6 104.4 104.2 104.0 103.8 109.9 109.8 109.7 109.6 109.5 109.4 109.3 109.2 109.1 109.0 108.9 F1 (ppm) F1 (ppm)

31 15 15 + - 15 Figure 3.26. P/ N HMQC spectra for H[PCl2 N]3 AlBr4 (a), [PCl2 N]4 (b), and

15 o 15 31 [PCl2 N]5 (c) in CD2Cl2 at 25 C. (F1 x axis: N NMR scale, F2 y axis: P NMR scale)

Figure 3.27. 15N NMR spectrum (left) and 31P NMR spectrum (right) for

15 + - o H[PCl2 N]3 CF3CO3 in C6D6 at 25 C. 91 Attempts to Isolate Protonated Impurities in [PCl2N]3.

Our work had suggested that impure [PCl2N]3 may contain acidic impurities.

Treatment of [PCl2N]3 with strong base (t-Bu)N=P(N(CH2)4)3 in hexane gives ~5% yield

+ - [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ], which slowly form a tan precipitate. This product can be rationalized as forming the deprotonation of [(PCl2N)2(P(OH)ClN)] by (t-

Bu)-N=P(N(CH2)4)3 as shown in Eq. 3.5. The latter compound would be expected to be formed from the reaction of [PCl2N]3 and adventitious water.

HO Cl O Cl P N H N P N N NN Cl Cl N P N N PN Cl Cl P P P P N hexane Cl N Cl N Cl N Cl

(Eq. 3.5)

+ - Crystals of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ] suitable for single

crystal x-ray diffraction studies were grown from a concentrated solution of dry hexane.

+ - The asymmetric unit contains one [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ] (Fig.

3.28). There is an oxygen atom bound to one of the phosphorus atoms of each trimer.

The P-N bonds associated with the phosphorus bound to the oxygen show single bond character at 1.625(3) Ǻ (P1-N1) and 1.626(3) Ǻ (P1-N3) with an average of 1.626 Ǻ.

The remaining P-N bonds range 1.552(3)-1.593(3) Ǻ with an average of 1.570 Ǻ. The P-

N bonds associated with nitrogen bound to the hydrogen in the protonated base show

92 single bond character at 1.618(3) Å (P4-N4), 1.622(2) Å (P4-N6), 1.628(2) Å (P4-N7),

1.631(3) Å (P4-N5), with an average of 1.625 Å.

31 + - The P NMR spectrum for [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ] (Fig.

3.29) showed a singlet at 22.7 ppm for the phosphorus cation. The triplet at -4.4 ppm (J

= 38 Hz) represents the phosphorus bound to oxygen and is split by the two other phosphorus atoms in the ring. These two phosphorus atoms are chemically equivalent and are split by the phosphorus bound to oxygen to yield a doublet at 20.9 ppm (J = 38

Hz). The 1H NMR spectrum provided evidence for the N-H bond with a doublet at 7.76

ppm (J = 8 Hz), illustrating that the H signal is split by phosphorus.

+ - Figure 3.28. Thermal ellipsoid plot of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ]. 93

20 15 10 5 0 -5 ppm

31 + - Figure 3.29. P NMR spectrum of [(t-Bu)NH-P(N(CH2)4)3 ][(PCl2N)2(POClN) ] in

o C6D6 at 25 C.

94 Synthesis and Characterization of Poly(dichlorophosphazene), [PCl2N]n.

As described in the introduction, the most successful polymerizations have

o involved catalysts based on BCl3 that gave high yields of linear polymer at 210 C in trichlorobenzene.5 Due to the various applications of phosphazenes, a successful industrial synthesis is of interest. In this work, attempts were made to improve the polymerization of [PCl2N]3 by the use of alternative catalysts. NaB(Ph)4, B(C6F5)3, and

SnCl2●2H2O were chosen to serve as catalysts. It was predicted that NaB(Ph)4 would serve as a noncoordinating anion to stabilize the cationic ends of the polymer chain. This in turn would provide a means for the ring-opening polymerization, ROP, to occur below

o - 210 C. B(C6F5)3 was chosen because it might abstract a Cl from the ring to initiate ROP or serve as an end group to the polymer, as has been proposed for BCl3. SnCl2●2H2O was chosen because it is known that traces of water can assist in the polymerization.13 As stated by Allcock, the ROP is difficult to reproduce due to traces of HCl impurities in

13 [PCl2N]3 or trace H2O on the walls of predried glassware. In fact, it is a challenge because some H2O can assist in the ROP whereas too much inhibits the process

13 completely. These irreproducibility issues led to the study of the reactivity of [PCl2N]3, described earlier, in order that the mechanism of the ROP can be understood in greater detail.

Melt polymerizations were conducted on small scale in sealed NMR tubes.

Polymerizations took place at 175oC, a significant improvement over the 250oC required

o for the uncatalyzed melt ROP and 210 C for the BCl3 catalyzed ROP in trichlorobenzene.

From the NMR spectroscopy, it was concluded that using NaB(Ph)4 allowed for short

31 chain polymers having a narrow resonance in the P NMR spectrum. For B(C6F5)3 and

95 31 SnCl2●2H2O, the resulting polymers showed broad resonances in the P NMR spectra.

In all cases, no insoluble crosslinked polymer was observed as described in Table 3.2.

Table 3.2. The results of various catalysts in the ROP of [PCl2N]3.

Linear Polymer & Catalyst Conditions Crosslinked 31P chemical shifts

o NaB(Ph)4 175 C for 24 h 90% at -17.6 ppm 0%

o B(C6F5)3 175 C for 24 h 69% at -17.7 ppm 0%

o SnCl2●2H2O 175 C for 24 h 97% at -17.4 ppm 0%

15 15 After the sublimation of [PCl2 N]3 in the initial synthesis, oligomeric [PCl2 N]n remained in the bottom of the tube as a thick liquid. Multinuclear NMR spectroscopy was conducted to obtain more information about the structure of this polymer. The 31P

NMR spectrum of the liquid showed three broad singlets for each of the following:

15 15 15 [PCl2 N]4 at -5.5 ppm, [PCl2 N]6 at -14.6 ppm, and [PCl2 N]n at -17.4 ppm (Fig. 3.30).

An additional resonance at -16.6 ppm is tentatively assigned as the end group of the

15 15 polymer. The N NMR showed two broad unresolved multiplets: ~90.7 % [PCl2 N]n at

202.7 ppm and ~9.3 % for a resonance tentatively assigned to the end groups at 203.8 ppm (Fig. 3.31).

A quantitative 31P NMR experiment as shown in Fig. 3.30 was conducted on the

INOVA 400 MHz in order to obtain an accurate molecular weight of the polymer in the thick liquid. It was found that the relaxation time of the end groups (T1 = 13s) was longer than that of the repeat units (T1 = 4.5s) and, therefore, d1 should be five times the value

of the T1, 65 s. The original setting for the experiment was d1 = 40, so this short 96 relaxation delay must be increased to d1 = 65 in order to allow time for the end groups to

15 relax. Then, the resonances were integrated to give 5.7% [PCl2 N]4 at -5.6 ppm, 14.5%

15 [PCl2 N]6 at -14.6 ppm, 7.1 % proposed PCl3 end groups at -16.7 ppm, and 72.7%

15 15 [PCl2 N]n at -17.4 ppm. After integration, it was found that n = 10.2 for [PCl2 N]n, and therefore, the molecular weight of the polymer is 2593, assuming PCl3 is the end group.

15 This shows that this polymer formed during the synthesis of [PCl2 N]3 is a short chain species.

31 15 15 A HMQC experiment provided a 2D P/ N spectrum for [PCl2 N]n (Fig. 3.32).

15 31 15 The correlation were tentatively assigned as [PCl2 N]4, P at -5.5 ppm and N at 208.4

15 31 15 31 ppm, [PCl2 N]6, P at -14.5 ppm and N at 203.1 ppm, PCl3 end groups, P at -16.6

15 15 31 15 ppm and N at 202.4 ppm, and [PCl2 N]n, P at -17.5 ppm and N at 201.9 ppm. This

15 data can be compared to the HMQC experiment for the starting material [PCl2 N]3, having the correlation, 31P at 20.6 ppm and 15N at 105.0 ppm as shown in Fig. 3.33. The other correlation, 31P at 20.6 ppm and 15N at 98.0 ppm could not be assigned to a particular compound.

In conclusion, the multinuclear NMR spectra, 31P/15N HMQC using one bond

correlations, was used to identify the products of superacid chemistry,

15 + - 15 + - 15 + - H[PCl2 N]3 SbCl6 , H[PCl2 N]3 AlBr4 , H[PCl2 N]3 CF3CO3 and as well as protonic

15 31 15 impurities in [PCl2 N]3. The 2D P/ N NMR experiments illustrated the correlations of both 31P and 15N nuclei with their corresponding compounds. From this information, the

15 assignments were given and end group were proposed for [PCl2 N]n. All techniques proved to be valuable tools for the characterization of these compounds.

ppm-20

-4 -8 -12 -16

Figure 3.30. Quantitative 31P NMR spectrum of the residue from the synthesis of

15 o [PCl2 N]3 in C6D6 at 25 C.

214 212 210 208 206 204 202 200 198 196 194 192 ppm

15 15 Figure 3.31. N NMR spectrum of the residue from the synthesis of [PCl2 N]3 in C6D6 at 25oC.

F1 (ppm) 200

201

202 A B

203 C

204

205

206

207

208 D 209

-5 -6 -7 -8 -10 -12 -14 -16 -18 F2 (ppm)

31 15 15 Figure 3.32. P/ N HMQC spectrum of residue from the synthesis of [PCl2 N]3 in

o 15 31 C6D6 at 25 C. (F1 y axis: N NMR scale, F2 x axis: P NMR scale)

100

F2 (ppm) 20.54

20.56 20.58 20.60

20.62 20.64 20.66

20.68 20.70 20.72

20.74

20.76 20.78

125 120 115 110 105 100 95 90 85 80 F1 (ppm)

31 15 15 o Figure 3.33. P/ N HMQC spectrum of [PCl2 N]3 in C6D6 at 25 C.

(F1 x axis: 15N NMR scale, F2 y axis: 31P NMR scale)

101 References and Notes

1) Allcock, H. R. “Complex and adduct formation,” Phosphorus-Nitrogen Compounds, Academic: New York, 1972; Chapter 11.

2) (a) Coxon, G. E.; Sowerby, D. B. J. Chem. Soc. A 1969, 3012-3014. (b) Bode, H., Bach, H. Chem. Ber. 1942, 75B, 215-226. (c) Goehring, M.; Hohenschutz, H.; Appel, R. Z. Naturforsch. 1954, 9b, 678-681.

3) Bode, H.; Bütow, K.; Lienau, G. Chem. Ber. 1948, 81, 547-552.

4) Gryff-Keller, A.; Molchanov, S. Mol. Phys. 2002, 100, 3349-3355.

5) Coxon, G. E.; Sowerby, D. B J. Chem. Soc. A 1969, 3012-3014.

6) (a) Schulz, S. Adv. Organomet. Chem. 2003, 49, 225-317. (b) Haaland, A. In Coordination Chemistry of Aluminum, Robinson, G. H., ed.; VCH: New York, 1993, 1- 56. (b) Krossing, I.; Nöth, H.; Schwenk-Kircher, H.; Seifert, T.; Tacke, C. Eur. J. Inorg. Chem. 1998, 1925-1930.

7) Rivard, E.; Lough, A.; Chivers, T.; Manners, I. Inorg. Chem. 2004, 43, 802-811.

8) (a) Nogai, S.; Schwriewer, A.; Schmidbaur, H. J. Chem. Soc., Dalton Trans. 2003, 3165-3171. (b) Ogawa, A.; Fujimoto, H. Inorg. Chem. 2002, 41, 4888-4894. (c) Cheng, Q. M.; Stark, O.; Merz, M.; Fischer, R. A. J. Chem. Soc., Dalton Trans. 2002, 2933- 2936.

9) Bellamy, L. The Infared Spectra of Complex Molecules, Wiley & Sons, New York, 1975; Chapter 18.

10) Farcasiu, D.; Fisk, S.; Melchior, M.; Rose, K. J. Org. Chem. 1982, 47, 453-457.

11) Kramer, G. J. Org. Chem. 1975, 40, 298-302.

12) Fujiwara, S.; Haraguchi, H. Nuclear Mag. Res. 1969, 73, 3467-3473.

13) Allcock, H. Chem. Rev. 1972, 72, 315-356.

102 CHAPTER IV

CARBOXYLATE DERIVATIVES OF DISILANES

Introduction

The motivation behind this area of research lies in the fact that the Si-Si short

contact in [Pt(PR3)2(µSiHR)]2 (Fig. 4.1) is not well understood. Our research group has studied these rings for many years. The Si--Si distance is on the long end of the range of

Si-Si single bonds, suggesting a bonding interaction. However, because each silicon atom is already engaged in four coordinate bonding interactions without the Si--Si interaction, it is unclear whether the short contact represents a bond. In order to gain a better understanding of these Pt-Si rings, systems that contain two five-coordinate silicon atoms that are engaged in Si-Si bonding are of interest. Panattoni and Dräger isolated 5-

R H Si

(PR3)2Pt Pt(PR3)2

Si HR

Figure 4.1. The structure of [Pt(PR3)2(µSiHR)]2 where R = alkyl or arly.

103 coordinate tin complexes having the general structure as shown in Eq. 4.1. The reaction

involved a diphenyl stannane and a carboxylic acid and was driven by the loss of

2 hydrogen. The crystal structure of Ph4Sn2(µ OOCCH3)2 had a Sn-Sn bond 2.69(1) Å and each Sn-O bond was 2.25(2) Å.1,2 Carboxylate derivatives of a digermane have been synthesized by Trimaille, having the structure shown in Eq. 4.2.3 The reaction involved hexaphenyl digermane and a carboxylic acid and loss of benzene was the driving force of

2Ph2SnH2 + 2RCOOH Ph4Sn2(OOCR)2 Ether R = Et, Me, n-Pr, i-Pr CH3 -2H2(g) t-Bu, Ph, Ph-CH3, C Ph C, CCl , or CF 3 3 3 O O

Sn Sn

O O C CH 3 (Eq. 4.1)

2 Ge2Ph6 + 2CX3COOH Ph4Ge2(µ OOCX3)2 Toluene X C -2PhH 3 X = F or Cl C O O

Ge Ge

O O C X C 3

(Eq. 4.2) 104 2 the reaction. The crystal structure of Ph4Ge2(µ OOCCl3)2 had a Ge-Ge bond of 239.3(2)

Å, and the Ge-O bond 207.3(3) Å and 231.4(3) Å.3 Because of the existence of these carboxylate derivatives of distannanes and digermanes, it seemed reasonable to attempt the synthesis of similar silicon compounds.

In 2003, Kawashima and coworkers synthesized the first structurally characterized heptacoordinate disilane as shown in Eq. 4.3.9 The reaction involved one equivalent of Si2Me2Cl4 and four equivalents of MesCS2K and was driven by the loss of

6 KCl. The crystal structure of Si2Me2(µ (SSCMes))4 had a Si-Si bond of 2.351(3) Å and the Si-S bonds were 2.165(3) Å, 2.183(3) Å, 3.315(3) Å, and 3.341(3) Å.9

Mes Mes S S Me S Si2Me2Cl4 + 4 MesCS K S Si Si S 2 Me THF S S -4KCl S Mes Mes (Eq. 4.3)

Experimental Section

General Procedures. All manipulations were preformed under argon, nitrogen, or vacuum using standard anaerobic techniques unless otherwise stated.4,5 The vacuum line had an ultimate capability of 2x10-4 torr. Elemental analyses were conducted by

Microanalysis Laboratory (Urbana, IL). All glassware was dried in the oven overnight

(~120oC) unless specified otherwise. Unless otherwise stated, reaction apparati were

either assembled hot and immediately subjected to vacuum on the Schlenk line or the hot

glassware was placed in the port of the glove box and immediately evacuated before

assembly in the glove box. The glassware used for the experiments was made with 105 virtually greaseless Fisher-Porter Solv-seal glass joints. High vacuum valves on the

flasks were purchased from Kimble-Kontes.

Materials. Toluene and tetrahydrofuran (Fisher) were predried over molecular

sieves and distilled from a sodium/benzophenone still. The N(CH3CH2)3 was dried over

+- BaO. The C30H18O4H, C14H8COOH, Si2(CH3)4Cl2, and Na C6H5CO2 (Aldrich) were used as received. C6D6 (Aldrich) and CDCl3 (Cambridge Isotopes) were dried several times with freshly activated 4 Å molecular sieves and stored under argon.

Routine Spectroscopy. The infrared spectra were collected on a Nicolet Nexus

870 Fourier transform spectrometer. The instrument was equipped with a Thunderdom

ATR accessory. The NMR spectra were obtained using a Gemini 300 MHZ or iNova

400 MHz spectrometers. The 29Si NMR (DEPT) spectra were referenced to trimethylsilane (0 ppm). The 1H and 13C NMR spectra were referenced to the proton and carbon resonance in the deuterated solvents.

X-ray crystallography. In the glove box, crystals were put into paratone oil on a slide. The slide was placed into a desiccator and was carried downstairs to the instrument. The crystals were immediately mounted and the data was collected.

Crystal structure analyses were done by Matthew Panzner. Crystal structure data sets were collected on a Bruker Apex CCD diffractometer with graphite-monochromated

Mo Kα radiation (λ = 0.71073 Å). Unit cell determination was achieved by using reflections from three different orientations. An empirical absorption correction and other corrections were applied using multi-scan SADABS. Structure solution, refinement and modeling were accomplished using the Bruker SHELXTL package.6 The structures

106 were obtained by full-matrix least-squares refinement of F2 and the selection of appropriate atoms from the generated difference map.

Preparation of Si2(CH3)4(C15H9O2)2. In a nitrogen glove bag, C30H18O4H (0.45 g, 2 mmol), Si2(CH3)4Cl2 (187 µL, 1 mmol), and N (CH3CH2)3 (279 µL, 2 mmol) were added to 25 mL of toluene at RT to give a cloudy yellow solution. The flask was brought out of the glove bag and a condenser was attached. The apparatus was placed into a preheated sand bath at 138oC. When reflux began, the solution became transparent and

turned deep yellow. The solution refluxed overnight (20 h), and cooled to yield a cloudy yellow solution. A light yellow precipitate was filtered through a frit and x-ray analysis

+ - found it to be triethylamine hydrochloride, N(CH3CH2)3H Cl . The filtrate was subject to vacuum to remove toluene and volatile materials. When almost all the solvent was removed, a yellow powder formed along the sides of the flask. A heat gun was used to warm the solution and swirling allowed all the powder to dissolve back into the solution.

This solution cooled and was allowed to stand to give yellow crystals within 15 min. The flask sat in the hood overnight. The next day, the yellow crystals were put into paratone oil for x-ray crystallography. The structure was found to be the disilane,

Si2(CH3)4(C15H9O2)2. The crystals were dried via the vacuum line for 4 h and the disilane

(0.181 g) was collected in the glove box for further characterization. Yield ~96%. Mp =

201-203°C. IR (Nujol mull) cm-1: 3068 (w), 1678 (vs), 1478 (m), 1327 (m), 1291 (m),

1249 (s), 1044 (m), 998 (m), 835 (m), 799 (s), 780 (s), 761 (m), 720 (m), 707 (m), 627

(m), 606 (w), 479 (w). Anal. calcd. for Si2(CH3)4(C15H9O2)2: C 73.07%; H 5.42%; and

1 1 found C 70.66%; H 5.41%. H NMR (C6D6, ppm): δ 9.10 (b, s), δ 8.51 (d, J Si-H = 8.7

Hz), δ 8.38 (b, m), δ 8.08 (m), δ 7.68 (m), δ 7.34 (overlapping, m), δ 7.07 (b, m), 6.76 (b,

107 m), 6.50 (b, s), 6.07 (b, s), 4.66 (b, s), δ 0.92 (s), δ 0.81 (s), δ 0.61 (b, m), 0.33 (b, m).

29 13 Si NMR (C6D6, ppm): δ 14.82 (s), C NMR (C6D6, ppm): δ 138.2 (s), δ 132.0 (s), δ

1 130.4 (s), δ 129.7 (s), δ 129.5 (s), δ 129.3 (s), δ 128.9 (s), δ 127.5 (s), 126.0 (d, JC-Si = 2

29 o Hz), δ 125.9 (s), δ 22.0 (s). Low temperature Si NMR (CDCl3, ppm) 30 C: δ 15.00 (s);

-20oC: δ 15.42 (s); -40oC: δ 15.66 (s). X-ray crystal structure analysis for

Si2(CH3)4(C15H9O2)2. Mw = 600.79, colorless crystal 0.48 x 0.26 x 0.15 mm, a =

11.9919(16) Å, b = 14.1914(19) Å, c = 19.818(3) Å, α = 90°, β = 109.449(2)°, γ = 90°, V

= 3180.2(8) Å3, Dcalc = 1.255 Mg m-3, µ = 0.151 mm-1, Z = 4, monoclinic, space group

P2(1)/c , λ = 0.71073 Å, T = 100 K, ω and φ scans, 28025 reflections collected, 7666

[R(int) = 0.0302], 410 refined parameters, R1/wR2 (I ≥ 2σ(I)) = 0.0604 / 0.1521 and

R1/wR2 (all data) = 0.0703 / 0.1578, maximum (minimum) residual electron density

- 0.521 (-0.354) e.Å-3. Mass spectra (negative mode): C15H9O2 m/z=220.9, C30H18O4H

/Na cluster m/z = 442.9, (positive mode), C30H18O4H /Na cluster m/z = 245.0. For

+ - 1 N(CH3CH2)3H Cl : H NMR (CDCl3, ppm): δ 11.90 (b, s), 3.13 (b, m), 1.43 (b, m).

Other Attempts to Prepare Carboxylate Derivatives of Disilanes.

In the nitrogen glove bag, sodium benzoate (0.43 g, 3 mmol) was added to a

Schlenk flask with 25 mL of toluene to yield a suspension. The Si2(CH3)4Cl2 (186 µL, 1 mmol) was added dropwise via syringe and the solution immediately became less cloudy.

The flask was attached to the Schlenk line and a condenser and bubbler were attached.

The apparatus was put into a sand bath at 140oC and refluxed for 18 h. The toluene and other volatile materials were removed under vacuum on the Schlenk line to yield crystals in transparent oil. The contents in the flask were evacuated for 4 h. The crystals were

108 found to be benzoic acid. The oil contained a mixture of proposed products: the mono-

29 and bis-substituted disilanes. Si NMR (C6D6, ppm): δ 14.8 (s), δ 2.6 (s).

In the nitrogen glove bag, sodium benzoate (0.32 g, 2.2 mmol) was added to a

Schlenk flask containing 30 mL of dry THF to yield a suspension. The Si2(CH3)4Cl2 (186

µL, 1 mmol) was added dropwise via syringe and the solution immediately became less cloudy. The flask was attached to the Schlenk line and a condenser and bubbler were attached. The apparatus was put into a preheated sand bath at 120oC and the heat was increased to 125oC and refluxed for 3 d. The flask was allowed to cool and the THF and other volatile materials were removed via the Schlenk line to yield colorless crystals in transparent oil. The contents were evacuated overnight with no change in appearance.

The mass spectrum provides evidence for the mono-substituted disilane. Mass spectra

29 (negative mode): Si2Cl(CH3)3(C15H9O2) m/z = 328.0. Si NMR (C6D6, ppm): δ 11.95

2 1 (s), δ 11.68 (s), δ 2.06 (d, JSi-H = 1.2 Hz), δ -16.88 (s). H NMR (C6D6, ppm): δ 8.18

1 13 (m), δ 8.08 (m), δ 7.04 (m), δ 0.66 (s), δ 0.44 (d, JC-H 10.5 Hz), C NMR (C6D6, ppm):

δ 168.97 (s), δ 167.86 (s), δ 134.01 (s), δ 133.55 (s), δ 133.38 (s), δ 131.97 (s), δ 131.68

(s), δ 130.85 (m), δ 128.81 (overlapping, m), δ 2.80 (s), δ -0.62 (s), δ -1.12 (s).

Results and Discussion

Synthesis.

The strategies used to synthesize the carboxylate derivatives of distannes and digermanes would not be expected to be successful. Silicon makes stronger bonds to carbon and hydrogen than germanium or tin. Also, carboxylate derivatives of monosilanes have been synthesized using precipitation of NaCl or NEt3HCl as the driving force. Therefore, similar routes were attempted for the synthesis of carboxylate

109 derivatives of disilanes. The initial reactions to synthesize new carboxylate derivatives

+- were unsuccessful. First, a 1:1 molar ratio of Si2(CH3)4Cl2 and Na CH3CO2 in THF was stirred at room temperature, but no reaction was observed (Eq. 4.4). A 1:1 molar reaction

+- was attempted involving Na C6H5CO2 with Si2Me4Cl2. In addition to the reagents, a small amount of C6H5CO2H was isolated. This could be due to the presence of

+- C6H5CO2H impurity in Na C6H5CO2.

CH3 CH3 O Cl Si Si Cl + RCONa No Reaction THF CH3 CH3 RT R = Me or Ph

(Eq. 4.4)

The next reaction involved more forcing conditions, Si2Me4Cl2 with three

+- equivalents of Na C6H5CO2 in refluxing toluene, a higher boiling solvent than THF. The product was a mixture of both mono- and bis- substituted disilanes, 1 and 2, (Eq. 4.5).

These products were difficult to separate, so further characterization was not conducted beyond this point. The next reactions were conducted to synthesize only one product.

The products 1 and 2 are drawn with bridging carboxylates, but this structural feature was never proven.

A synthesis involving a 1:2.2 molar ratio of Si2Me4Cl2 to C6H5CO2H yielded the same mono-substituted product 1, (Eq. 4.6). For this reaction, the starting materials were refluxed in THF for a 3 d period. The mono-substituted product was identified by its mass spectrum, but crystal growth was unsuccessful.

110 O O O O CH ClMe Si SiMe Cl CH3 3 2 2 CH3 Toluene Si Si + CH3 Si Si + CH reflux 18h CH CH3 3 O 3 O O CH3 Cl 3 Na OC Ph

1 2

(Eq. 4.5)

O CH3 CH3 O O Cl Si Si Cl O 2.2 Na THF CH3 CH3 CH3 reflux 3d CH3 Si Si CH3 CH3 Cl

(Eq. 4.6)

A different carboxylic acid, C14H8COOH, and a different synthetic strategy gave

the desired compound. This reaction involved a 1:2:2 molar ratio of Si2Me4Cl2,

C14H8COOH, and triethylamine. The amine served as a trap for the HCl byproduct. The

111 NEt3HCl precipitated from toluene and could be easily removed via filtration. This

reaction produced crystals which were found to be the bis-substituted disilane,

Si2(CH3)4(C15H9O2)2 (3), (Eq. 4.7).

CH CH O O 3 3 2 CH CH3 + + 2 Et N 3 Cl Si Si Cl 3 Si Si Toluene CH3 CH3 CH3 CH OOH Reflux 20 h 3 O O

(Eq. 4.7)

Some challenges were found in the synthesis of all three compounds above.

Compounds 1 and 2 proved to be difficult to separate effectively, hence the reason for

changing the starting materials. There was a need to find a way to control impurities that

interfered in these reactions. First, HCl protonated the sodium benzoate and, therefore,

producing benzoic acid in the reaction. After this acid was determined by X-ray analysis,

it was clear that HCl was an inhibitor in the synthesis of new carboxylic acid derivatives

of Si2Me4Cl2. Once the sensitivity issues were identified and controlled, it was possible

to adjust the experiments in order to isolate just one species. The Et3N was found to be

112 necessary here to trap HCl, forming NEt3HCl. The precipitate from the toluene solution and filtered from the reaction. Finally, compound 3 was successfully isolated.

NMR Spectroscopy.

NMR spectroscopy was used to determine the substituents of the products.

Multiple resonances observed in the 29Si NMR spectra indicated that a mixture of compounds 1 and 2 as synthesized in the earlier reactions. A broad resonance (δ 11.90

1 ppm) in the H NMR spectra showed the presence of the N-H bond of the salt, NEt3HCl.

After this salt was removed, compound 3 was isolated. 29Si NMR spectroscopy for compound 3 provided a single resonance, at 14.82 ppm in C6D6, indicating the product was the bis-substituted product and not a mixture of products.

In addition, low temperature NMR spectroscopy was conducted on 3 in CDCl3.

The following resonances were observed in the 29Si NMR spectrum: 30oC: δ 15.00 (s);

-20oC: δ 15.42 (s); -40oC: δ 15.66 (s). The chemical shift at 30oC is consistent with a four coordinate silicon compound. As the temperature was decreased to -20oC then to

-60oC, it was clear that the silicon remains four coordinate for compound 3. If a large upfield shift was observed, the conclusion would be that the carboxylate group had a strong interaction at low temperature. However, because there was no significant shift in the resonance, it was concluded that the carboxylate group has a very weak interaction to silicon and the group moves freely in solution.

X-ray Crystallography.

X-ray analysis verified the identification of this salt impurity, NEt3HCl by unit cell comparison. The thermal ellipsoid plot for compound 3 is shown in Figure 4.2. The structure shows a distorted trigonal bipyramidal at silicon. The Si-Si bond is 2.326 Å

113 which is comparable to the germanium complex (Eq. 4.2) having a Ge-Ge bond of

2.393(2) Å. Both are longer than that found the distannane (Eq. 4.1) having a Sn-Sn

bond 2.711(1) Å and the Sn-O bonds were equal in length (2.25(2) Å).1 In contrast, the four coordinate silicon in 3 has two distinct Si-O bond distances: 1.732 Å (ave) and

3.092 Å (ave).1 This supports the fact that silicon remains four coordinate in the crystalline form. The first Si-O bond found for compound 3 was at the top of the range of a typical Si-O bond (1.55-1.78 Å) for tetracoordinate silicon.7 The second distance is much longer indicating this is more likely a weak O→Si dative bond which are generally

2.0 Å or longer.7

Figure 4.2. Thermal ellipsoid plot of Si2(CH3)4(C15H9O2)2.

Table 4.1 illustrates the bond angles for compound 3. The O-Ge-O and O-Sn-O

o bond angles for compounds, Ge2Ph4(OOCCCl3)2 (175.4(1) ) and Sn2Ph4(OOCCCl3)2

114 (168.2(1) o) were larger than the O-Si-O angle for compound 3 (167.58(7)o).3,8 The O-Si-

O was in the range for a typical O-Si-X bond angle, where X ≠ Si (90-180o), for tetracoordinate silicon.7 In contrast, the O-M-M angles for compound 3 were very different than those for Ge2Ph4(OOCCCl3)2 and Sn2Ph4(OOCCCl3)2. The O-Ge-Ge bond angles were 91.9(1) o and 83.8(1) o for an average of 87.9o.3 The O-Sn-Sn bond angles were 168.3(4) o. The O-Si-Si bond angles were very different, 107.26(6) o and 60.79(3) o, illustrating the asymmetry of 3. The larger angle represents the angle at the silicon which has the dative bond to the oxygen atom whereas the smaller angle is that involving the silicon covalently bound to the oxygen atom.

Table 4.1. Bond angles for compound 3.

Compound 3 Bond Angles Average

112.21(12)° CH3-Si-CH3 112.06° (ave) 111.91(12)°

167.58(7)° O-Si---O 169.04° (ave) 170.50(6)°

102.88(10)°

105.63(9)° O-Si-CH3 103.76° (ave) 102.10(9)° 104.41(9)°

84.24(8)°

79.26(8)° O---Si-CH3 82.00° (ave) 78.60(8)° 85.88(8)°

Table 4.2 illustrates the bond lengths for distannane and digermane compounds

synthesized by Dräger and Trimaille.3,8 This work shows that the Si-Si distance for 3 is

115 the shortest M-M bond and the bond length increases in order of increasing atomic radii,

giving the distannane the longest Sn-Sn bond of 2.711(1) Å. This is in agreement for the trend going down a group in the periodic table. The Si-Si bond for compound 3 is also similar to the Si-Si bond (2.351(3) Å) for Kawashima’s disilane that is bound to phenyl groups and sulfur ligands.9 The M-O bonds also follow this trend with the average of the

Si-O bond is the shortest and the Sn-O bond is the longest.

Table 4.2. Comparison of bond angles.

Compound M-M (Å) M-O (Å) M---O (Å) Reference

Si2(CH3)4(C15H9O2)2 2.326(8) 1.732 (ave) 3.092 (ave) This Work

Ge2Ph4(OOCCCl3)2 2.393(2) 2.073(3) 2.314(3) Trimaille, 1984

Sn2Ph4(OOCCCl3)2 2.711(1) 2.295(3) 2.322(3) Dräger, 1987

116 References and Notes

1) Panattoni, C.; Bandoli, G.; Clemente, D. Chem. Comm. 1971, 311-312.

2) Tagliavini, G.; Peruzzo, V.; Plazzogna, G. J Organomet. Chem. 1974, 66, 57-61.

3) Trimaille, B.; Theobald, F. J Organomet. Chem. 1984, 267, 143-149.

4) Shriver, D. F.; Drexdon, M. A. The Manipulation of Air-Sensitive Compounds, 2nd ed.; Wiley: New York, 1986.

5) Plesch, P. H. High Vacuum Techniques for Chemical Syntheses and Measurements, Cambridge University Press: New York, 1989.

6) Sheldrick, G. M. SHELX97: Programs for Crystal Structural Analysis; University of Göttingen, Göttingen, Germany 1997.

7) Botoshansky, M.; Kaftory, M.; Kapon, M. In The Chemistry of Organic Silicon Compounds; Apeloig, Y.; Pappoport, Z. Eds.; The Structural Chemistry of Orgaonsilicon Compounds, Vol. II, Part I, Wiley: New York, 1998, Ch. 5.

8) Dräger, M.; Adams, S.; Mathiasch, B. J Organomet. Chem. 1987, 326, 173-186.

9) Kawashima, T.; Kano, N.; Nakagawa, N. Angew. Chem. Int. Ed. 2001, 40, 3450-3452.

117 APPENDIX

SUPPLEMENTARY MATERIALS FOR ALL X-RAY CRYSTAL STRUCTURES

15 Asymmetric Unit: [PCl2 N]3

118 15 Molecule: [PCl2 N]3

119 15 Table 1. Crystal data and structure refinement for [PCl2 N]3. 15 Identification code Cl6 N3P3 Empirical formula Cl6 15N3 P3 Formula weight 350.64 Temperature 373(2) K Wavelength 0.71073 Å Crystal system Orthorhombic Space group Pnma Unit cell dimensions a = 13.878(4) Å α= 90°. b = 12.830(4) Å β= 90°. c = 6.0881(18) Å γ = 90°. Volume 1084.0(5) Å3 Z 4 Density (calculated) 2.130 Mg/m3 Absorption coefficient 1.977 mm-1 F(000) 672 Crystal size 0.46 x 0.45 x 0.21 mm3 Theta range for data collection 2.94 to 28.25°. Index ranges -18 ≤ h ≤ 18, -16 ≤ k ≤ 17, -7 ≤ l ≤ 8 Reflections collected 8755 Independent reflections 1370 [R(int) = 0.0280] Completeness to theta = 28.25° 98.0 % Absorption correction Semi-empirical from equivalents Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 1370 / 0 / 61 Goodness-of-fit on F2 1.227 Final R indices [I>2sigma(I)] R1 = 0.0271, wR2 = 0.0648 R indices (all data) R1 = 0.0285, wR2 = 0.0654 Largest diff. peak and hole 0.682 and -0.480 e.Å-3

120 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 ij for [PCl2 N]3. U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Cl(1) -1020(1) 7500 794(1) 22(1) Cl(2) -1876(1) 7500 5470(1) 20(1) Cl(3) 853(1) 5703(1) 8474(1) 22(1) Cl(4) 1825(1) 5488(1) 3918(1) 21(1) P(1) -608(1) 7500 3924(1) 14(1) P(2) 952(1) 6428(1) 5583(1) 14(1) N(1) -70(1) 6441(1) 4444(3) 19(1) N(2) 1491(2) 7500 5944(4) 20(1) ______

121 15 Table 3. Bond lengths [Å] and angles [°] for [PCl2 N]3. ______Cl(1)-P(1) 1.9897(11) Cl(2)-P(1) 1.9959(10) Cl(3)-P(2) 1.9950(8) Cl(4)-P(2) 1.9876(7) P(1)-N(1)#1 1.5821(17) P(1)-N(1) 1.5822(17) P(2)-N(1) 1.5795(16) P(2)-N(2) 1.5810(13) N(2)-P(2)#1 1.5810(13)

N(1)#1-P(1)-N(1) 118.37(12) N(1)#1-P(1)-Cl(1) 109.11(7) N(1)-P(1)-Cl(1) 109.11(7) N(1)#1-P(1)-Cl(2) 108.76(7) N(1)-P(1)-Cl(2) 108.76(7) Cl(1)-P(1)-Cl(2) 101.41(4) N(1)-P(2)-N(2) 118.44(10) N(1)-P(2)-Cl(4) 109.27(7) N(2)-P(2)-Cl(4) 108.11(9) N(1)-P(2)-Cl(3) 109.28(7) N(2)-P(2)-Cl(3) 108.40(10) Cl(4)-P(2)-Cl(3) 102.09(3) P(2)-N(1)-P(1) 121.38(10) P(2)-N(2)-P(2)#1 120.97(15) ______Symmetry transformations used to generate equivalent atoms: #1 x,-y+3/2,z

122 2 3 15 Table 4. Anisotropic displacement parameters (Å x 10 ) for [PCl2 N]3. The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Cl(1) 20(1) 30(1) 15(1) 0 -4(1) 0 Cl(2) 13(1) 26(1) 22(1) 0 3(1) 0 Cl(3) 24(1) 24(1) 18(1) 4(1) 1(1) 1(1) Cl(4) 19(1) 22(1) 23(1) -3(1) 3(1) 5(1) P(1) 10(1) 16(1) 15(1) 0 -2(1) 0 P(2) 11(1) 14(1) 17(1) 0(1) -2(1) 1(1) N(1) 14(1) 15(1) 27(1) -1(1) -6(1) -1(1) N(2) 13(1) 16(1) 30(1) 0 -7(1) 0 ______

123 15 Asymmetric Unit: [PCl2 N]3•AlBr3

124 15 Two Molecules: [PCl2 N]3•AlBr3

125 15 Adduct: [PCl2 N]3•AlBr3

126 15 Table 1. Crystal data and structure refinement for [PCl2 N]3•AlBr3. 15 Identification code AlBr3Cl6 N3P3 Empirical formula Al Br3 Cl6 15N3 P3 Formula weight 617.35 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/m Unit cell dimensions a = 10.9235(9) Å α= 90°. b = 12.1204(10) Å β= 91.8480(10)°. c = 12.1583(10) Å γ = 90°. Volume 1608.9(2) Å3 Z 4 Density (calculated) 2.536 Mg/m3 Absorption coefficient 8.847 mm-1 F(000) 1144 Crystal size 0.31 x 0.26 x 0.23 mm3 Theta range for data collection 1.68 to 28.27°. Index ranges -14 ≤ h ≤ 14, -16 ≤ k ≤ 16, -15 ≤ l ≤ 16 Reflections collected 14427 Independent reflections 4038 [R(int) = 0.0388] Completeness to theta = 28.27° 96.7 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.2354 and 0.1701 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 4038 / 0 / 163 Goodness-of-fit on F2 1.044 Final R indices [I>2sigma(I)] R1 = 0.0293, wR2 = 0.0574 R indices (all data) R1 = 0.0371, wR2 = 0.0595 Largest diff. peak and hole 0.568 and -0.619 e.Å-3

127 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 ij for [PCl2 N]3•AlBr3. U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Br(1) 9942(1) 9006(1) 6168(1) 18(1) Br(2) 8172(1) 7500 8367(1) 16(1) Br(3) 4387(1) 2500 9490(1) 19(1) Br(4) 5860(1) 982(1) 11935(1) 19(1) Cl(1) 7453(1) 9244(1) 4017(1) 20(1) Cl(2) 6892(1) 9752(1) 6474(1) 16(1) Cl(3) 4063(1) 7500 3115(1) 18(1) Cl(4) 2869(1) 7500 5414(1) 18(1) Cl(5) 6776(1) 272(1) 9263(1) 19(1) Cl(6) 8946(1) 712(1) 10955(1) 21(1) Cl(7) 9485(1) 2500 6598(1) 28(1) Cl(8) 11350(1) 2500 8562(1) 29(1) P(1) 6583(1) 8664(1) 5303(1) 10(1) P(2) 4475(1) 7500 4732(1) 11(1) P(3) 8087(1) 1331(1) 9639(1) 12(1) P(4) 9561(1) 2500 8222(1) 15(1) Al(1) 8811(1) 7500 6612(1) 11(1) Al(2) 5887(1) 2500 10835(1) 12(1) N(1) 7262(3) 7500 5699(3) 11(1) N(2) 5176(2) 8599(2) 5031(2) 15(1) N(3) 7420(3) 2500 9999(3) 9(1) N(4) 8970(3) 1401(2) 8655(2) 20(1) ______

128 15 Table 3. Bond lengths [Å] and angles [°] for [PCl2 N]3•AlBr3. ______Br(1)-Al(1) 2.2787(8) Br(2)-Al(1) 2.2666(14) Br(3)-Al(2) 2.2771(14) Br(4)-Al(2) 2.2753(9) Cl(1)-P(1) 1.9834(11) Cl(2)-P(1) 1.9622(11) Cl(3)-P(2) 2.0028(16) Cl(4)-P(2) 1.9643(15) Cl(5)-P(3) 1.9658(11) Cl(6)-P(3) 1.9768(12) Cl(7)-P(4) 1.9729(17) Cl(8)-P(4) 1.9844(16) P(1)-N(2) 1.564(3) P(1)-N(1) 1.6580(19) P(2)-N(2) 1.574(3) P(2)-N(2)#1 1.574(3) P(3)-N(4) 1.563(3) P(3)-N(3) 1.6581(19) P(4)-N(4) 1.578(3) P(4)-N(4)#2 1.578(3) Al(1)-N(1) 1.994(4) Al(1)-Br(1)#1 2.2787(8) Al(2)-N(3) 1.987(4) Al(2)-Br(4)#2 2.2753(9) N(1)-P(1)#1 1.6580(19) N(3)-P(3)#2 1.6581(19)

N(2)-P(1)-N(1) 116.48(15) N(2)-P(1)-Cl(2) 109.35(11) N(1)-P(1)-Cl(2) 107.24(12) N(2)-P(1)-Cl(1) 110.13(11) N(1)-P(1)-Cl(1) 108.01(13) Cl(2)-P(1)-Cl(1) 104.99(5) 129 N(2)-P(2)-N(2)#1 115.7(2) N(2)-P(2)-Cl(4) 109.69(10) N(2)#1-P(2)-Cl(4) 109.69(10) N(2)-P(2)-Cl(3) 108.64(11) N(2)#1-P(2)-Cl(3) 108.64(11) Cl(4)-P(2)-Cl(3) 103.80(7) N(4)-P(3)-N(3) 116.24(15) N(4)-P(3)-Cl(5) 108.68(12) N(3)-P(3)-Cl(5) 107.28(11) N(4)-P(3)-Cl(6) 110.58(12) N(3)-P(3)-Cl(6) 108.16(13) Cl(5)-P(3)-Cl(6) 105.30(5) N(4)-P(4)-N(4)#2 115.1(2) N(4)-P(4)-Cl(7) 109.26(12) N(4)#2-P(4)-Cl(7) 109.26(12) N(4)-P(4)-Cl(8) 109.95(11) N(4)#2-P(4)-Cl(8) 109.95(11) Cl(7)-P(4)-Cl(8) 102.60(7) N(1)-Al(1)-Br(2) 104.03(12) N(1)-Al(1)-Br(1) 108.96(7) Br(2)-Al(1)-Br(1) 114.14(4) N(1)-Al(1)-Br(1)#1 108.96(7) Br(2)-Al(1)-Br(1)#1 114.14(4) Br(1)-Al(1)-Br(1)#1 106.46(5) N(3)-Al(2)-Br(4)#2 109.12(7) N(3)-Al(2)-Br(4) 109.12(7) Br(4)#2-Al(2)-Br(4) 107.91(6) N(3)-Al(2)-Br(3) 103.39(12) Br(4)#2-Al(2)-Br(3) 113.56(4) Br(4)-Al(2)-Br(3) 113.56(4) P(1)#1-N(1)-P(1) 116.6(2) P(1)#1-N(1)-Al(1) 121.68(10) P(1)-N(1)-Al(1) 121.68(10) P(1)-N(2)-P(2) 123.99(17) P(3)-N(3)-P(3)#2 117.4(2) 130 P(3)-N(3)-Al(2) 121.29(10) P(3)#2-N(3)-Al(2) 121.29(10) P(3)-N(4)-P(4) 124.83(18) ______Symmetry transformations used to generate equivalent atoms: #1 x,-y+3/2,z #2 x,-y+1/2,z

131 2 3 15 Table 4. Anisotropic displacement parameters (Å x 10 ) for [PCl2 N]3•AlBr3. The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Br(1) 14(1) 21(1) 20(1) 5(1) -1(1) -7(1) Br(2) 19(1) 18(1) 11(1) 0 2(1) 0 Br(3) 10(1) 32(1) 14(1) 0 -2(1) 0 Br(4) 20(1) 20(1) 16(1) 5(1) 1(1) -4(1) Cl(1) 22(1) 22(1) 16(1) 8(1) 1(1) -3(1) Cl(2) 19(1) 11(1) 19(1) -5(1) -4(1) 1(1) Cl(3) 24(1) 17(1) 12(1) 0 -3(1) 0 Cl(4) 10(1) 28(1) 17(1) 0 0(1) 0 Cl(5) 21(1) 16(1) 21(1) -6(1) 1(1) -5(1) Cl(6) 19(1) 21(1) 23(1) 5(1) -5(1) 6(1) Cl(7) 20(1) 51(1) 12(1) 0 -1(1) 0 Cl(8) 9(1) 57(1) 22(1) 0 -2(1) 0 P(1) 11(1) 8(1) 12(1) 0(1) -1(1) -1(1) P(2) 9(1) 11(1) 13(1) 0 -2(1) 0 P(3) 12(1) 10(1) 15(1) -1(1) 1(1) 1(1) P(4) 10(1) 22(1) 13(1) 0 1(1) 0 Al(1) 9(1) 12(1) 12(1) 0 0(1) 0 Al(2) 10(1) 16(1) 11(1) 0 1(1) 0 N(1) 9(2) 10(2) 14(2) 0 -2(1) 0 N(2) 13(1) 10(1) 22(2) -1(1) -4(1) 3(1) N(3) 8(2) 11(2) 9(2) 0 -1(1) 0 N(4) 21(2) 17(2) 22(2) -1(1) 8(1) 4(1) ______

132 15 Asymmetric Unit: [PCl2 N]3•GaCl3

133 15 Adduct: [PCl2 N]3•GaCl3

134 15 Table 1. Crystal data and structure refinement for [PCl2 N]3•GaCl3. 15 Identification code Cl9Ga N3P3 Empirical formula Cl9 Ga 15N3 P3 Formula weight 526.71 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/c Unit cell dimensions a = 11.7624(11) Å α= 90°. b = 10.7999(10) Å β= 91.989(2)°. c = 23.873(2) Å γ = 90°. Volume 3030.8(5) Å3 Z 8 Density (calculated) 2.295 Mg/m3 Absorption coefficient 3.693 mm-1 F(000) 2000 Crystal size 0.28 x 0.15 x 0.04 mm3 Theta range for data collection 1.71 to 28.32°. Index ranges -15 ≤ h ≤ 15, -13 ≤ k ≤ 14, -31 ≤ l ≤ 30 Reflections collected 26454 Independent reflections 7291 [R(int) = 0.0525] Completeness to theta = 28.32° 96.5 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.8663 and 0.4245 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 7291 / 0 / 289 Goodness-of-fit on F2 1.085 Final R indices [I>2sigma(I)] R1 = 0.0405, wR2 = 0.0847 R indices (all data) R1 = 0.0503, wR2 = 0.0882 Largest diff. peak and hole 1.056 and -0.541 e.Å-3

135 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 ij for [PCl2 N]3•GaCl3. U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Ga(1) 3404(1) 6116(1) 1184(1) 12(1) Ga(2) 10958(1) 738(1) 1310(1) 15(1) Cl(1) 9360(1) 1882(1) 2415(1) 22(1) Cl(2) 11182(1) 3884(1) 2160(1) 26(1) Cl(3) 9344(1) 1683(1) 142(1) 21(1) Cl(4) 11120(1) 3790(1) 371(1) 24(1) Cl(5) 6635(1) 4555(1) 1204(1) 29(1) Cl(6) 8623(1) 6429(1) 1194(1) 26(1) Cl(7) 12009(1) 775(1) 2061(1) 24(1) Cl(8) 9624(1) -616(1) 1308(1) 26(1) Cl(9) 12002(1) 667(1) 589(1) 22(1) Cl(10) 3486(1) 8017(1) 2357(1) 19(1) Cl(11) 6024(1) 7392(1) 2151(1) 21(1) Cl(12) 3533(1) 8149(1) 80(1) 16(1) Cl(13) 6068(1) 7524(1) 366(1) 19(1) Cl(14) 4567(1) 12132(1) 1289(1) 20(1) Cl(15) 6950(1) 10890(1) 1345(1) 23(1) Cl(16) 3898(1) 5034(1) 1907(1) 21(1) Cl(17) 1675(1) 6746(1) 1178(1) 20(1) Cl(18) 3868(1) 5118(1) 448(1) 20(1) P(1) 9771(1) 3116(1) 1851(1) 15(1) P(2) 9743(1) 3021(1) 669(1) 14(1) P(3) 8312(1) 4629(1) 1218(1) 16(1) P(4) 4706(1) 8334(1) 1835(1) 13(1) P(5) 4740(1) 8418(1) 654(1) 12(1) P(6) 5292(1) 10492(1) 1289(1) 13(1) N(1) 10084(2) 2379(3) 1274(1) 14(1) N(2) 8751(3) 3986(3) 673(1) 21(1) N(3) 8793(3) 4084(3) 1792(1) 27(1) N(4) 4340(2) 7715(2) 1228(1) 13(1) 136 N(5) 5017(2) 9831(3) 711(1) 15(1) N(6) 4970(3) 9752(3) 1829(1) 18(1) ______

137 15 Table 3. Bond lengths [Å] and angles [°] for [PCl2 N]3•GaCl3. ______Ga(1)-N(1) 2.049(3) Ga(1)-Cl(17) 2.1444(9) Ga(1)-Cl(18) 2.1473(9) Ga(1)-Cl(16) 2.1492(9) Ga(2)-N(4) 2.048(3) Ga(2)-Cl(7) 2.1425(10) Ga(2)-Cl(8) 2.1451(10) Ga(2)-Cl(9) 2.1505(10) Cl(1)-P(1) 1.9658(13) Cl(2)-P(1) 1.9744(13) Cl(3)-P(2) 1.9618(12) Cl(4)-P(2) 1.9741(13) Cl(5)-P(3) 1.9733(13) Cl(6)-P(3) 1.9795(13) Cl(10)-P(4) 1.9631(13) Cl(11)-P(4) 1.9811(12) Cl(12)-P(5) 1.9601(12) Cl(13)-P(5) 1.9803(12) Cl(14)-P(6) 1.9660(12) Cl(15)-P(6) 1.9963(13) P(1)-N(3) 1.558(3) P(1)-N(1) 1.644(3) P(2)-N(2) 1.565(3) P(2)-N(1) 1.640(3) P(3)-N(2) 1.576(3) P(3)-N(3) 1.578(3) P(4)-N(6) 1.563(3) P(4)-N(4) 1.641(3) P(5)-N(5) 1.566(3) P(5)-N(4) 1.648(3) P(6)-N(6) 1.574(3) P(6)-N(5) 1.577(3)

138 N(4)-Ga(1)-Cl(17) 103.93(8) N(4)-Ga(1)-Cl(18) 108.28(8) Cl(17)-Ga(1)-Cl(18) 114.94(4) N(4)-Ga(1)-Cl(16) 106.73(8) Cl(17)-Ga(1)-Cl(16) 114.06(4) Cl(18)-Ga(1)-Cl(16) 108.36(4) N(1)-Ga(2)-Cl(7) 107.04(8) N(1)-Ga(2)-Cl(8) 102.95(9) Cl(7)-Ga(2)-Cl(8) 114.52(4) N(1)-Ga(2)-Cl(9) 107.27(8) Cl(7)-Ga(2)-Cl(9) 109.98(4) Cl(8)-Ga(2)-Cl(9) 114.33(4) N(3)-P(1)-N(1) 115.81(16) N(3)-P(1)-Cl(1) 108.60(14) N(1)-P(1)-Cl(1) 108.23(11) N(3)-P(1)-Cl(2) 111.11(15) N(1)-P(1)-Cl(2) 107.82(12) Cl(1)-P(1)-Cl(2) 104.65(6) N(2)-P(2)-N(1) 115.81(16) N(2)-P(2)-Cl(3) 109.44(13) N(1)-P(2)-Cl(3) 107.42(11) N(2)-P(2)-Cl(4) 110.07(13) N(1)-P(2)-Cl(4) 108.44(11) Cl(3)-P(2)-Cl(4) 105.09(6) N(2)-P(3)-N(3) 115.75(16) N(2)-P(3)-Cl(5) 108.93(13) N(3)-P(3)-Cl(5) 109.10(14) N(2)-P(3)-Cl(6) 110.03(13) N(3)-P(3)-Cl(6) 109.28(14) Cl(5)-P(3)-Cl(6) 102.98(6) N(6)-P(4)-N(4) 115.86(15) N(6)-P(4)-Cl(10) 109.10(12) N(4)-P(4)-Cl(10) 108.33(11) N(6)-P(4)-Cl(11) 110.77(13) N(4)-P(4)-Cl(11) 107.76(11) 139 Cl(10)-P(4)-Cl(11) 104.38(6) N(5)-P(5)-N(4) 116.24(15) N(5)-P(5)-Cl(12) 110.36(12) N(4)-P(5)-Cl(12) 106.95(11) N(5)-P(5)-Cl(13) 109.94(12) N(4)-P(5)-Cl(13) 108.39(11) Cl(12)-P(5)-Cl(13) 104.23(5) N(6)-P(6)-N(5) 116.03(15) N(6)-P(6)-Cl(14) 109.87(12) N(5)-P(6)-Cl(14) 109.40(12) N(6)-P(6)-Cl(15) 108.45(13) N(5)-P(6)-Cl(15) 109.09(12) Cl(14)-P(6)-Cl(15) 103.22(5) P(2)-N(1)-P(1) 118.60(17) P(2)-N(1)-Ga(2) 120.62(16) P(1)-N(1)-Ga(2) 120.70(16) P(2)-N(2)-P(3) 124.3(2) P(1)-N(3)-P(3) 124.8(2) P(4)-N(4)-P(5) 118.20(17) P(4)-N(4)-Ga(1) 120.84(16) P(5)-N(4)-Ga(1) 120.96(15) P(5)-N(5)-P(6) 123.52(18) P(4)-N(6)-P(6) 124.01(19) ______Symmetry transformations used to generate equivalent atoms:

140 2 3 15 Table 4. Anisotropic displacement parameters (Å x 10 ) for [PCl2 N]3•GaCl3. The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Ga(1) 13(1) 9(1) 15(1) 1(1) 1(1) 0(1) Ga(2) 13(1) 9(1) 21(1) -1(1) 0(1) 2(1) Cl(1) 25(1) 22(1) 19(1) 6(1) 6(1) 2(1) Cl(2) 33(1) 18(1) 26(1) -6(1) -3(1) -7(1) Cl(3) 22(1) 20(1) 20(1) -7(1) -5(1) 3(1) Cl(4) 26(1) 22(1) 25(1) 2(1) 8(1) -7(1) Cl(5) 17(1) 18(1) 54(1) 5(1) 6(1) 0(1) Cl(6) 21(1) 12(1) 46(1) -1(1) 1(1) 0(1) Cl(7) 24(1) 24(1) 25(1) 4(1) -6(1) 6(1) Cl(8) 21(1) 11(1) 46(1) -3(1) 5(1) -3(1) Cl(9) 17(1) 23(1) 27(1) -8(1) 4(1) 2(1) Cl(10) 23(1) 17(1) 17(1) 2(1) 6(1) 1(1) Cl(11) 21(1) 20(1) 22(1) -1(1) -7(1) 5(1) Cl(12) 18(1) 16(1) 15(1) 0(1) -4(1) -2(1) Cl(13) 17(1) 18(1) 24(1) -2(1) 6(1) 3(1) Cl(14) 22(1) 10(1) 27(1) -1(1) 1(1) 0(1) Cl(15) 15(1) 26(1) 29(1) -1(1) -3(1) -4(1) Cl(16) 26(1) 15(1) 23(1) 7(1) -4(1) 0(1) Cl(17) 14(1) 23(1) 23(1) 1(1) 1(1) 3(1) Cl(18) 23(1) 15(1) 23(1) -6(1) 5(1) -2(1) P(1) 21(1) 11(1) 13(1) -1(1) 2(1) 4(1) P(2) 17(1) 11(1) 14(1) 0(1) 1(1) 2(1) P(3) 17(1) 11(1) 21(1) 2(1) 2(1) 5(1) P(4) 16(1) 11(1) 12(1) 1(1) 0(1) 1(1) P(5) 13(1) 9(1) 13(1) 0(1) 0(1) -1(1) P(6) 15(1) 10(1) 16(1) -1(1) 0(1) -1(1) N(1) 14(1) 11(1) 15(2) 0(1) 2(1) 4(1) N(2) 29(2) 18(2) 16(2) 5(1) -1(1) 12(1) N(3) 38(2) 26(2) 17(2) -3(1) 3(2) 19(2) N(4) 16(1) 9(1) 14(1) 0(1) 0(1) -2(1) 141 N(5) 20(2) 9(1) 15(2) 4(1) 1(1) -4(1) N(6) 26(2) 12(1) 15(2) -1(1) 0(1) -4(1) ______

142 15 Asymmetric Unit: [PCl2 N]3•AlCl3

143 15 Adduct: [PCl2 N]3•AlCl3

144 15 Side View: [PCl2 N]3•AlCl3

145 15 Table 1. Crystal data and structure refinement for [PCl2 N]3•AlCl3. 15 Identification code AlCl9 N3P3 Empirical formula Al Cl9 15N3 P3 Formula weight 483.97 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Orthorhombic Space group Pmn2(1) Unit cell dimensions a = 11.9974(11) Å α= 90°. b = 11.7111(11) Å β= 90°. c = 10.7768(10) Å γ = 90°. Volume 1514.2(2) Å3 Z 4 Density (calculated) 2.110 Mg/m3 Absorption coefficient 2.013 mm-1 F(000) 928 Crystal size 0.11 x 0.09 x 0.05 mm3 Theta range for data collection 1.74 to 28.26°. Index ranges -15 ≤ h ≤ 15, -14 ≤ k ≤ 15, -14 ≤ l ≤ 14 Reflections collected 13259 Independent reflections 3798 [R(int) = 0.0368] Completeness to theta = 28.26° 98.8 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.9061 and 0.8138 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 3798 / 1 / 163 Goodness-of-fit on F2 1.275 Final R indices [I>2sigma(I)] R1 = 0.0428, wR2 = 0.0874 R indices (all data) R1 = 0.0446, wR2 = 0.0881 Absolute structure parameter 0.04(12) Largest diff. peak and hole 0.737 and -0.445 e.Å-3

146 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 ij for [PCl2 N]3•AlCl3. U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Cl(1) 1423(1) 1085(1) 10020(1) 23(1) Cl(2) 0 3278(1) 8437(1) 18(1) Cl(3) 1791(1) -1046(1) 7716(1) 20(1) Cl(4) 2270(1) 1491(1) 7015(1) 20(1) Cl(5) 0 -1980(1) 4223(2) 37(1) Cl(6) 0 415(1) 3007(1) 21(1) Cl(7) 1442(1) 3007(1) 4368(1) 25(1) Cl(8) 0 5354(1) 5650(2) 31(1) Cl(9) 1830(1) 3773(1) 1301(1) 24(1) Cl(10) 2241(1) 5671(1) 3277(1) 24(1) Cl(11) 0 6326(1) -1419(1) 32(1) Cl(12) 0 8282(1) 503(1) 24(1) P(1) 1177(1) 262(1) 6767(1) 13(1) P(2) 0 -327(1) 4647(1) 15(1) P(3) 1180(1) 5181(1) 1994(1) 14(1) P(4) 0 6600(1) 387(1) 15(1) Al(1) 0 1552(2) 8991(2) 13(1) Al(2) 0 4036(2) 4315(2) 16(1) N(1) 0 654(4) 7438(4) 11(1) N(2) 1108(3) -33(3) 5350(3) 21(1) N(3) 0 4843(4) 2703(4) 13(1) N(4) 1108(3) 6127(4) 971(4) 26(1) ______

147 15 Table 3. Bond lengths [Å] and angles [°] for [PCl2 N]3•AlCl3. ______Cl(1)-Al(1) 2.1084(15) Cl(2)-Al(1) 2.107(2) Cl(3)-P(1) 1.9834(14) Cl(4)-P(1) 1.9654(15) Cl(5)-P(2) 1.989(2) Cl(6)-P(2) 1.970(2) Cl(7)-Al(2) 2.1088(15) Cl(8)-Al(2) 2.110(2) Cl(9)-P(3) 1.9713(15) Cl(10)-P(3) 1.9642(15) Cl(11)-P(4) 1.972(2) Cl(12)-P(4) 1.974(2) P(1)-N(2) 1.567(4) P(1)-N(1) 1.652(3) P(2)-N(2)#1 1.569(4) P(2)-N(2) 1.569(4) P(3)-N(4) 1.565(4) P(3)-N(3) 1.657(3) P(4)-N(4) 1.572(4) P(4)-N(4)#1 1.572(4) Al(1)-N(1) 1.977(5) Al(1)-Cl(1)#1 2.1084(15) Al(2)-N(3) 1.978(5) Al(2)-Cl(7)#1 2.1088(15) N(1)-P(1)#1 1.652(3) N(3)-P(3)#1 1.657(3)

N(2)-P(1)-N(1) 116.3(2) N(2)-P(1)-Cl(4) 109.19(15) N(1)-P(1)-Cl(4) 107.86(15) N(2)-P(1)-Cl(3) 110.62(15) N(1)-P(1)-Cl(3) 107.87(17) Cl(4)-P(1)-Cl(3) 104.35(7) 148 N(2)#1-P(2)-N(2) 115.9(3) N(2)#1-P(2)-Cl(6) 109.67(15) N(2)-P(2)-Cl(6) 109.67(15) N(2)#1-P(2)-Cl(5) 108.95(15) N(2)-P(2)-Cl(5) 108.95(15) Cl(6)-P(2)-Cl(5) 102.88(10) N(4)-P(3)-N(3) 116.5(2) N(4)-P(3)-Cl(10) 108.97(17) N(3)-P(3)-Cl(10) 107.41(17) N(4)-P(3)-Cl(9) 110.29(17) N(3)-P(3)-Cl(9) 108.19(18) Cl(10)-P(3)-Cl(9) 104.76(7) N(4)-P(4)-N(4)#1 115.6(3) N(4)-P(4)-Cl(11) 109.75(17) N(4)#1-P(4)-Cl(11) 109.75(17) N(4)-P(4)-Cl(12) 109.02(17) N(4)#1-P(4)-Cl(12) 109.02(17) Cl(11)-P(4)-Cl(12) 103.01(9) N(1)-Al(1)-Cl(2) 105.69(16) N(1)-Al(1)-Cl(1) 107.90(9) Cl(2)-Al(1)-Cl(1) 113.46(6) N(1)-Al(1)-Cl(1)#1 107.90(9) Cl(2)-Al(1)-Cl(1)#1 113.46(6) Cl(1)-Al(1)-Cl(1)#1 108.15(10) N(3)-Al(2)-Cl(7)#1 107.24(10) N(3)-Al(2)-Cl(7) 107.24(10) Cl(7)#1-Al(2)-Cl(7) 110.26(10) N(3)-Al(2)-Cl(8) 104.42(17) Cl(7)#1-Al(2)-Cl(8) 113.55(7) Cl(7)-Al(2)-Cl(8) 113.55(7) P(1)#1-N(1)-P(1) 117.5(3) P(1)#1-N(1)-Al(1) 121.24(14) P(1)-N(1)-Al(1) 121.24(14) P(1)-N(2)-P(2) 124.3(2) P(3)-N(3)-P(3)#1 117.4(3) 149 P(3)-N(3)-Al(2) 121.27(14) P(3)#1-N(3)-Al(2) 121.27(14) P(3)-N(4)-P(4) 125.3(2) ______Symmetry transformations used to generate equivalent atoms: #1 -x,y,z

150 2 3 15 Table 4. Anisotropic displacement parameters (Å x 10 ) for [PCl2 N]3•AlCl3. The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Cl(1) 25(1) 24(1) 19(1) -3(1) -9(1) 8(1) Cl(2) 17(1) 11(1) 26(1) 1(1) 0 0 Cl(3) 22(1) 17(1) 21(1) 5(1) 3(1) 7(1) Cl(4) 14(1) 22(1) 24(1) 5(1) -1(1) -5(1) Cl(5) 66(1) 15(1) 31(1) -6(1) 0 0 Cl(6) 29(1) 22(1) 14(1) 2(1) 0 0 Cl(7) 27(1) 23(1) 26(1) 8(1) -6(1) 4(1) Cl(8) 59(1) 22(1) 12(1) -3(1) 0 0 Cl(9) 25(1) 26(1) 22(1) -2(1) 5(1) 7(1) Cl(10) 21(1) 24(1) 28(1) 0(1) -9(1) -7(1) Cl(11) 68(1) 18(1) 11(1) 1(1) 0 0 Cl(12) 38(1) 15(1) 18(1) -1(1) 0 0 P(1) 11(1) 15(1) 13(1) 1(1) 0(1) 1(1) P(2) 20(1) 13(1) 13(1) -2(1) 0 0 P(3) 12(1) 17(1) 14(1) 4(1) 0(1) 0(1) P(4) 18(1) 16(1) 11(1) 5(1) 0 0 Al(1) 15(1) 12(1) 12(1) 0(1) 0 0 Al(2) 25(1) 13(1) 10(1) 3(1) 0 0 N(1) 8(2) 10(2) 14(2) -3(2) 0 0 N(2) 17(2) 28(2) 18(2) -3(2) 4(2) 4(2) N(3) 16(2) 14(2) 10(2) 6(2) 0 0 N(4) 16(2) 32(2) 30(2) 19(2) 5(2) 2(2) ______

151 15 + - Asymmetric Unit: H[PCl2 N]3 SbCl6

152 15 + Cation: H[PCl2 N]3

153 - Anion: SbCl6

154 15 + - Table 1. Crystal data and structure refinement for H[PCl2 N]3 SbCl6 . 15 Identification code Cl12 N3P3Sb Empirical formula Cl12 15N3 P3 Sb Formula weight 685.09 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Orthorhombic Space group Pna2(1) Unit cell dimensions a = 16.0656(17) Å α= 90°. b = 10.0854(11) Å β= 90°. c = 11.7766(12) Å γ = 90°. Volume 1908.1(3) Å3 Z 4 Density (calculated) 2.374 Mg/m3 Absorption coefficient 3.363 mm-1 F(000) 1284 Crystal size 0.14 x 0.10 x 0.08 mm3 Theta range for data collection 2.38 to 28.27°. Index ranges -21 ≤ h ≤ 21, -12 ≤ k ≤ 13, -15 ≤ l ≤ 15 Reflections collected 16343 Independent reflections 4572 [R(int) = 0.0623] Completeness to theta = 28.27° 98.6 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.7747 and 0.6503 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 4572 / 1 / 172 Goodness-of-fit on F2 1.039 Final R indices [I>2sigma(I)] R1 = 0.0412, wR2 = 0.0802 R indices (all data) R1 = 0.0491, wR2 = 0.0824 Absolute structure parameter 0.51(2) Largest diff. peak and hole 0.644 and -0.708 e.Å-3

155 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 + - ij for H[PCl2 N]3 SbCl6 . U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Sb(1) 632(1) 3053(1) 3772(1) 14(1) Cl(1) 7405(1) -183(2) 10976(1) 23(1) Cl(2) 8798(1) 1914(2) 11174(1) 26(1) Cl(3) 7335(1) 190(2) 6895(2) 27(1) Cl(4) 8800(1) 2195(2) 6908(2) 23(1) Cl(5) 5593(1) 2324(2) 9021(1) 26(1) Cl(6) 6537(1) 5001(1) 9247(1) 22(1) Cl(7) 479(1) 3993(2) 1963(1) 22(1) Cl(8) 363(1) 901(2) 2977(2) 26(1) Cl(9) -809(1) 3365(2) 4082(1) 22(1) Cl(10) 959(1) 5147(2) 4549(2) 28(1) Cl(11) 2063(1) 2626(2) 3477(1) 22(1) Cl(12) 736(1) 2052(2) 5583(2) 37(1) P(1) 7823(1) 1431(2) 10267(1) 12(1) P(2) 7822(1) 1638(2) 7780(1) 14(1) P(3) 6724(1) 3087(1) 9115(1) 13(1) N(1) 8167(3) 998(5) 8994(4) 15(1) N(2) 7208(3) 2791(5) 7963(4) 17(1) N(3) 7177(3) 2572(5) 10226(4) 16(1) ______

156 15 + - Table 3. Bond lengths [Å] and angles [°] for H[PCl2 N]3 SbCl6 . ______Sb(1)-Cl(7) 2.3445(17) Sb(1)-Cl(10) 2.3609(17) Sb(1)-Cl(11) 2.3645(14) Sb(1)-Cl(9) 2.3646(15) Sb(1)-Cl(12) 2.3652(18) Sb(1)-Cl(8) 2.4030(17) Cl(1)-P(1) 1.949(2) Cl(2)-P(1) 1.958(2) Cl(3)-P(2) 1.956(2) Cl(4)-P(2) 1.960(2) Cl(5)-P(3) 1.976(2) Cl(6)-P(3) 1.959(2) P(1)-N(3) 1.549(5) P(1)-N(1) 1.656(5) P(2)-N(2) 1.540(5) P(2)-N(1) 1.664(5) P(3)-N(3) 1.585(5) P(3)-N(2) 1.592(5)

Cl(7)-Sb(1)-Cl(10) 90.79(6) Cl(7)-Sb(1)-Cl(11) 92.39(6) Cl(10)-Sb(1)-Cl(11) 90.17(6) Cl(7)-Sb(1)-Cl(9) 89.11(5) Cl(10)-Sb(1)-Cl(9) 92.25(6) Cl(11)-Sb(1)-Cl(9) 177.14(6) Cl(7)-Sb(1)-Cl(12) 177.66(7) Cl(10)-Sb(1)-Cl(12) 90.94(7) Cl(11)-Sb(1)-Cl(12) 89.18(6) Cl(9)-Sb(1)-Cl(12) 89.25(6) Cl(7)-Sb(1)-Cl(8) 89.57(6) Cl(10)-Sb(1)-Cl(8) 177.46(6) Cl(11)-Sb(1)-Cl(8) 87.30(6) Cl(9)-Sb(1)-Cl(8) 90.27(6) 157 Cl(12)-Sb(1)-Cl(8) 88.76(7) N(3)-P(1)-N(1) 113.0(3) N(3)-P(1)-Cl(1) 113.8(2) N(1)-P(1)-Cl(1) 106.43(19) N(3)-P(1)-Cl(2) 111.6(2) N(1)-P(1)-Cl(2) 106.98(19) Cl(1)-P(1)-Cl(2) 104.43(10) N(2)-P(2)-N(1) 112.7(3) N(2)-P(2)-Cl(3) 112.5(2) N(1)-P(2)-Cl(3) 107.56(19) N(2)-P(2)-Cl(4) 111.7(2) N(1)-P(2)-Cl(4) 107.11(19) Cl(3)-P(2)-Cl(4) 104.80(11) N(3)-P(3)-N(2) 114.7(3) N(3)-P(3)-Cl(6) 109.1(2) N(2)-P(3)-Cl(6) 109.1(2) N(3)-P(3)-Cl(5) 109.9(2) N(2)-P(3)-Cl(5) 109.1(2) Cl(6)-P(3)-Cl(5) 104.32(10) P(1)-N(1)-P(2) 124.3(3) P(2)-N(2)-P(3) 125.0(3) P(1)-N(3)-P(3) 125.2(3) ______Symmetry transformations used to generate equivalent atoms:

158 2 3 15 + - Table 4. Anisotropic displacement parameters (Å x 10 ) for H[PCl2 N]3 SbCl6 . The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Sb(1) 10(1) 16(1) 16(1) 1(1) 0(1) 2(1) Cl(1) 24(1) 15(1) 29(1) 8(1) 10(1) 4(1) Cl(2) 18(1) 36(1) 24(1) -5(1) -8(1) -1(1) Cl(3) 36(1) 24(1) 21(1) -5(1) -5(1) -2(1) Cl(4) 21(1) 26(1) 22(1) 7(1) 10(1) 4(1) Cl(5) 17(1) 31(1) 30(1) 3(1) -2(1) -7(1) Cl(6) 28(1) 10(1) 28(1) 1(1) -3(1) 5(1) Cl(7) 19(1) 31(1) 17(1) 5(1) 0(1) -4(1) Cl(8) 15(1) 16(1) 48(1) -5(1) -9(1) 1(1) Cl(9) 14(1) 29(1) 23(1) 7(1) 2(1) 5(1) Cl(10) 24(1) 26(1) 34(1) -13(1) -10(1) 8(1) Cl(11) 9(1) 23(1) 32(1) -6(1) 1(1) 1(1) Cl(12) 26(1) 59(1) 27(1) 21(1) 0(1) 11(1) P(1) 13(1) 13(1) 12(1) 2(1) -1(1) 1(1) P(2) 15(1) 14(1) 12(1) 2(1) 2(1) 2(1) P(3) 12(1) 12(1) 15(1) 3(1) -1(1) 2(1) N(1) 19(2) 20(2) 8(3) 4(2) -3(2) 7(2) N(2) 19(3) 19(3) 11(3) 7(2) 0(2) 3(2) N(3) 16(3) 14(3) 16(3) 3(2) 4(2) 2(2) ______

159 + - Asymmetric Unit: H[PCl2N]3 AlBr4

160 + - Table 1. Crystal data and structure refinement for H[PCl2N]3 AlBr4 .

Identification code AlBr4Cl6N3P3 Empirical formula Al Br4 Cl6 N3 P3 Formula weight 694.26 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P-1 Unit cell dimensions a = 7.6634(9) Å α= 84.630(2)°. b = 9.9155(12) Å β= 85.081(2)°. c = 12.3237(15) Å γ = 73.214(2)°. Volume 890.90(19) Å3 Z 2 Density (calculated) 2.588 Mg/m3 Absorption coefficient 10.234 mm-1 F(000) 642 Crystal size 0.07 x 0.06 x 0.03 mm3 Theta range for data collection 2.15 to 27.49°. Index ranges -9 ≤ h ≤ 9, -12 ≤ k ≤ 12, -15 ≤ l ≤ 15 Reflections collected 7467 Independent reflections 3902 [R(int) = 0.0302] Completeness to theta = 27.49° 95.5 % Max. and min. transmission 0.7488 and 0.5344 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 3902 / 0 / 154 Goodness-of-fit on F2 1.091 Final R indices [I>2sigma(I)] R1 = 0.0421, wR2 = 0.1168 R indices (all data) R1 = 0.0534, wR2 = 0.1339 Largest diff. peak and hole 1.746 and -1.249 e.Å-3

161 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103)

+ - ij for H[PCl2N]3 AlBr4 . U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Br(1) 4733(1) 7443(1) 1621(1) 22(1) Br(2) 3142(1) 5232(1) 3949(1) 18(1) Br(3) 52(1) 8751(1) 3043(1) 24(1) Br(4) 4264(1) 8497(1) 4510(1) 27(1) Cl(1) 10386(2) 2339(2) 4076(1) 23(1) Cl(2) 8571(2) 5438(2) 3220(1) 20(1) Cl(3) 4366(2) 3821(2) 1196(1) 22(1) Cl(4) 5438(2) 933(2) 2540(1) 23(1) Cl(5) 9764(2) 3510(2) -598(1) 25(1) Cl(6) 11947(2) 710(2) 570(1) 26(1) P(1) 9080(2) 3487(2) 2845(1) 16(1) P(2) 6457(2) 2415(2) 1856(1) 16(1) P(3) 9838(2) 2355(2) 807(1) 15(1) Al 3040(2) 7508(2) 3261(2) 17(1) N(1) 10201(7) 3235(6) 1734(4) 20(1) N(2) 7062(7) 3172(6) 2856(4) 22(1) N(3) 8056(7) 1837(5) 1004(4) 17(1) ______

162 + - Table 3. Bond lengths [Å] and angles [°] for H[PCl2N]3 AlBr4 . ______Br(1)-Al 2.302(2) Br(2)-Al 2.317(2) Br(3)-Al 2.2909(19) Br(4)-Al 2.2959(19) Cl(1)-P(1) 1.969(2) Cl(2)-P(1) 1.952(2) Cl(3)-P(2) 1.973(2) Cl(4)-P(2) 1.949(2) Cl(5)-P(3) 1.979(2) Cl(6)-P(3) 1.961(2) P(1)-N(1) 1.553(5) P(1)-N(2) 1.663(5) P(2)-N(3) 1.555(5) P(2)-N(2) 1.664(5) P(3)-N(3) 1.585(5) P(3)-N(1) 1.590(5)

N(1)-P(1)-N(2) 113.1(3) N(1)-P(1)-Cl(2) 111.7(2) N(2)-P(1)-Cl(2) 106.0(2) N(1)-P(1)-Cl(1) 112.7(2) N(2)-P(1)-Cl(1) 107.7(2) Cl(2)-P(1)-Cl(1) 104.92(9) N(3)-P(2)-N(2) 113.2(3) N(3)-P(2)-Cl(4) 111.9(2) N(2)-P(2)-Cl(4) 107.0(2) N(3)-P(2)-Cl(3) 112.7(2) N(2)-P(2)-Cl(3) 107.0(2) Cl(4)-P(2)-Cl(3) 104.41(10) N(3)-P(3)-N(1) 115.9(3) N(3)-P(3)-Cl(6) 108.6(2) N(1)-P(3)-Cl(6) 110.2(2) N(3)-P(3)-Cl(5) 109.8(2) 163 N(1)-P(3)-Cl(5) 108.2(2) Cl(6)-P(3)-Cl(5) 103.40(10) Br(3)-Al-Br(4) 110.47(8) Br(3)-Al-Br(1) 110.71(8) Br(4)-Al-Br(1) 109.84(8) Br(3)-Al-Br(2) 108.46(8) Br(4)-Al-Br(2) 107.43(8) Br(1)-Al-Br(2) 109.85(8) P(1)-N(1)-P(3) 125.5(3) P(1)-N(2)-P(2) 123.0(3) P(2)-N(3)-P(3) 124.7(3) ______Symmetry transformations used to generate equivalent atoms:

164 2 3 + - Table 4. Anisotropic displacement parameters (Å x 10 ) for H[PCl2N]3 AlBr4 . The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Br(1) 21(1) 24(1) 16(1) 4(1) -1(1) -2(1) Br(2) 17(1) 17(1) 20(1) 3(1) -2(1) -3(1) Br(3) 20(1) 24(1) 22(1) 4(1) -4(1) 1(1) Br(4) 39(1) 29(1) 18(1) 2(1) -8(1) -19(1) Cl(1) 24(1) 24(1) 20(1) 5(1) -8(1) -5(1) Cl(2) 20(1) 20(1) 20(1) 1(1) -5(1) -5(1) Cl(3) 17(1) 26(1) 21(1) 3(1) -6(1) -2(1) Cl(4) 22(1) 26(1) 24(1) 7(1) -3(1) -14(1) Cl(5) 34(1) 28(1) 14(1) 6(1) -4(1) -11(1) Cl(6) 21(1) 22(1) 33(1) -2(1) 0(1) -1(1) P(1) 13(1) 22(1) 14(1) 0(1) -3(1) -7(1) P(2) 16(1) 21(1) 13(1) 2(1) -3(1) -7(1) P(3) 14(1) 18(1) 13(1) 1(1) -2(1) -5(1) Al 17(1) 17(1) 17(1) 1(1) -5(1) -6(1) N(1) 15(3) 30(3) 13(2) 0(2) 2(2) -6(2) N(2) 19(3) 37(3) 16(3) -7(2) 0(2) -18(2) N(3) 12(2) 13(2) 27(3) -1(2) -7(2) -5(2) ______

165 15 + - Asymmetric Unit: H[PCl2 N]3 AlBr4

166 15 + Cation: H[PCl2 N]3

167 - Anion: AlBr4

168 15 + Cation (alternate view): H[PCl2 N]3

169 15 + Twisted Molecule: H[PCl2 N]3

170 Twisted Molecule (alternate view): 15 + H[PCl2 N]3

171 15 + - Table 1. Crystal data and structure refinement for H[PCl2 N]3 AlBr4 . 15 Identification code AlBr4Cl6 N3P3 Empirical formula Al Br4 Cl6 N3 P3 Formula weight 697.26 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P-1 Unit cell dimensions a = 7.6721(9) Å α= 84.643(2)°. b = 9.9263(12) Å β= 85.055(2)°. c = 12.3245(14) Å γ = 73.178(2)°. Volume 892.77(18) Å3 Z 2 Density (calculated) 2.583 Mg/m3 Absorption coefficient 10.212 mm-1 F(000) 642 Crystal size 0.10 x 0.06 x 0.03 mm3 Theta range for data collection 1.66 to 28.31°. Index ranges -10 ≤ h ≤ 10, -13 ≤ k ≤ 13, -15 ≤ l ≤ 15 Reflections collected 7915 Independent reflections 4117 [R(int) = 0.0248] Completeness to theta = 28.31° 92.6 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.7493 and 0.5444 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 4117 / 0 / 154 Goodness-of-fit on F2 1.035 Final R indices [I>2sigma(I)] R1 = 0.0342, wR2 = 0.0702 R indices (all data) R1 = 0.0461, wR2 = 0.0736 Largest diff. peak and hole 0.870 and -0.679 e.Å-3

172 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) 15 + - ij for H[PCl2 N]3 AlBr4 . U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Br(1) 4731(1) 7444(1) 1621(1) 20(1) Br(2) 3145(1) 5232(1) 3948(1) 17(1) Br(3) 54(1) 8753(1) 3041(1) 23(1) Br(4) 4267(1) 8495(1) 4509(1) 25(1) Cl(1) 10382(2) 2342(1) 4072(1) 21(1) Cl(2) 8570(1) 5441(1) 3219(1) 18(1) Cl(3) 5435(2) 933(1) 2541(1) 22(1) Cl(4) 4367(1) 3819(1) 1195(1) 22(1) Cl(5) 11950(2) 709(1) 571(1) 24(1) Cl(6) 9765(2) 3511(1) -599(1) 24(1) P(1) 9085(1) 3487(1) 2847(1) 14(1) P(2) 6456(1) 2419(1) 1855(1) 14(1) P(3) 9839(1) 2359(1) 804(1) 14(1) Al 3049(2) 7509(1) 3260(1) 16(1) N(1) 7065(5) 3177(4) 2848(3) 20(1) N(2) 8064(5) 1848(4) 1008(3) 17(1) N(3) 10191(5) 3234(4) 1731(3) 17(1) ______

173 15 + - Table 3. Bond lengths [Å] and angles [°] for H[PCl2 N]3 AlBr4 . ______Br(1)-Al 2.2967(13) Br(2)-Al 2.3212(14) Br(3)-Al 2.2975(14) Br(4)-Al 2.2942(13) Cl(1)-P(1) 1.9610(15) Cl(2)-P(1) 1.9549(15) Cl(3)-P(2) 1.9562(15) Cl(4)-P(2) 1.9710(15) Cl(5)-P(3) 1.9652(15) Cl(6)-P(3) 1.9774(15) P(1)-N(3) 1.554(3) P(1)-N(1) 1.665(3) P(2)-N(2) 1.554(3) P(2)-N(1) 1.661(4) P(3)-N(2) 1.579(3) P(3)-N(3) 1.583(3)

N(3)-P(1)-N(1) 112.25(18) N(3)-P(1)-Cl(2) 111.79(14) N(1)-P(1)-Cl(2) 105.91(14) N(3)-P(1)-Cl(1) 113.12(15) N(1)-P(1)-Cl(1) 108.08(14) Cl(2)-P(1)-Cl(1) 105.18(6) N(2)-P(2)-N(1) 112.46(18) N(2)-P(2)-Cl(3) 112.28(14) N(1)-P(2)-Cl(3) 107.33(14) N(2)-P(2)-Cl(4) 112.89(14) N(1)-P(2)-Cl(4) 107.05(14) Cl(3)-P(2)-Cl(4) 104.31(7) N(2)-P(3)-N(3) 115.26(18) N(2)-P(3)-Cl(5) 108.73(14) N(3)-P(3)-Cl(5) 110.30(14) N(2)-P(3)-Cl(6) 110.01(14) 174 N(3)-P(3)-Cl(6) 108.35(14) Cl(5)-P(3)-Cl(6) 103.54(7) Br(4)-Al-Br(1) 110.01(5) Br(4)-Al-Br(3) 110.48(5) Br(1)-Al-Br(3) 110.62(5) Br(4)-Al-Br(2) 107.44(5) Br(1)-Al-Br(2) 109.91(5) Br(3)-Al-Br(2) 108.30(5) P(2)-N(1)-P(1) 123.6(2) P(2)-N(2)-P(3) 125.6(2) P(1)-N(3)-P(3) 126.2(2) ______Symmetry transformations used to generate equivalent atoms:

175 2 3 15 + - Table 4. Anisotropic displacement parameters (Å x 10 ) for H[PCl2 N]3 AlBr4 . The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Br(1) 20(1) 22(1) 16(1) 1(1) 2(1) -2(1) Br(2) 15(1) 15(1) 19(1) 0(1) 1(1) -3(1) Br(3) 18(1) 21(1) 23(1) 1(1) -1(1) 2(1) Br(4) 37(1) 27(1) 18(1) -1(1) -5(1) -19(1) Cl(1) 23(1) 21(1) 18(1) 3(1) -4(1) -4(1) Cl(2) 20(1) 16(1) 19(1) -3(1) -2(1) -5(1) Cl(3) 22(1) 23(1) 25(1) 4(1) -1(1) -13(1) Cl(4) 18(1) 22(1) 22(1) 0(1) -3(1) -2(1) Cl(5) 18(1) 19(1) 33(1) -5(1) 3(1) 0(1) Cl(6) 32(1) 26(1) 15(1) 3(1) 0(1) -10(1) P(1) 13(1) 18(1) 13(1) -2(1) 0(1) -7(1) P(2) 13(1) 17(1) 14(1) -1(1) -1(1) -6(1) P(3) 14(1) 16(1) 13(1) -1(1) 1(1) -4(1) Al 17(1) 15(1) 14(1) -1(1) -2(1) -3(1) N(1) 15(2) 32(2) 18(2) -7(2) 2(2) -14(2) N(2) 15(2) 20(2) 15(2) -6(2) 0(1) -6(2) N(3) 14(2) 23(2) 17(2) -5(2) 4(1) -10(2) ______

176 Protonated Base & Oxygenated Trimer: - + [(PCl2N)2(POClN) ][(t-Bu)NH-P(N(CH2)4)3 ]

177 - Anion: [(PCl2N)2(POClN) ]

178 + Cation: [(t-Bu)NH-P(N(CH2)4)3 ]

179 - + Table 1. Crystal data and structure refinement for [(PCl2N)2(POClN) ][(t-Bu)NH-P(N(CH2)4)3 ].

Identification code P3N3Cl5O C16H34N4P Empirical formula C16 H34 Cl5 N7 O P4 Formula weight 641.63 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group Pn Unit cell dimensions a = 9.386(4) Å α= 90°. b = 9.937(4) Å β= 97.062(7)°. c = 15.714(6) Å γ = 90°. Volume 1454.5(10) Å3 Z 2 Density (calculated) 1.465 Mg/m3 Absorption coefficient 0.743 mm-1 F(000) 664 Crystal size 0.24 x 0.04 x 0.04 mm3 Theta range for data collection 2.05 to 28.32°. Index ranges -12 ≤ h ≤ 12, -13 ≤ k ≤ 12, -20 ≤ l ≤ 20 Reflections collected 12554 Independent reflections 6591 [R(int) = 0.0307] Completeness to theta = 28.32° 96.0 % Max. and min. transmission 0.9709 and 0.8418 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 6591 / 2 / 305 Goodness-of-fit on F2 1.028 Final R indices [I>2sigma(I)] R1 = 0.0408, wR2 = 0.0878 R indices (all data) R1 = 0.0475, wR2 = 0.0909 Absolute structure parameter 0.00(6) Largest diff. peak and hole 0.570 and -0.399 e.Å-3

180 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) - + for [(PCl2N)2(POClN) ][(t-Bu)NH-P(N(CH2)4)3 ]. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ______x y z U(eq) ______Cl(1) 4682(1) 6566(1) 8647(1) 38(1) Cl(2) 1106(1) 4381(1) 7873(1) 31(1) Cl(3) -1315(1) 6452(1) 7943(1) 33(1) Cl(4) 401(1) 7825(1) 10768(1) 37(1) Cl(5) 2796(1) 5692(1) 10991(1) 35(1) P(1) 3026(1) 7918(1) 8725(1) 23(1) P(2) 741(1) 6149(1) 8429(1) 20(1) P(3) 1731(1) 6846(1) 10067(1) 23(1) P(4) 6047(1) 1265(1) 19(1) 15(1) O 3531(2) 9219(2) 8444(2) 29(1) N(1) 1680(3) 7280(3) 8106(2) 26(1) N(2) 798(3) 5866(3) 9430(2) 27(1) N(3) 2764(3) 7884(3) 9728(2) 28(1) N(4) 6068(3) 807(3) -968(2) 17(1) N(5) 4351(3) 1567(2) 68(2) 19(1) N(6) 6979(3) 2600(2) 304(2) 19(1) N(7) 6689(3) 98(2) 686(1) 16(1) C(1) 7256(3) 779(3) -1507(2) 23(1) C(2) 8567(3) 30(4) -1057(2) 27(1) C(3) 6686(4) -1(4) -2317(2) 30(1) C(4) 7650(4) 2213(4) -1742(2) 33(1) C(9) 3337(3) 2200(4) -604(2) 31(1) C(10) 1908(4) 1826(5) -372(3) 48(1) C(11) 2127(3) 1767(4) 607(2) 31(1) C(12) 3652(4) 1273(4) 828(2) 35(1) C(8) 6373(3) 3954(3) 112(3) 30(1) C(7) 7656(4) 4886(4) 311(3) 51(1) C(6) 8634(4) 4133(4) 992(3) 40(1) C(5) 8503(3) 2698(3) 670(2) 27(1) 181 C(13) 6998(3) 283(3) 1633(2) 25(1) C(14) 6296(4) -942(4) 1990(2) 32(1) C(15) 6500(4) -2027(4) 1359(2) 36(1) C(16) 6319(4) -1341(3) 483(2) 22(1) ______

182 - + Table 3. Bond lengths [Å] and angles [°] for [(PCl2N)2(POClN) ][(t-Bu)NH-P(N(CH2)4)3 ]. ______Cl(1)-P(1) 2.0697(14) Cl(2)-P(2) 2.0103(13) Cl(3)-P(2) 2.0085(13) Cl(4)-P(3) 2.0138(13) Cl(5)-P(3) 2.0154(12) P(1)-O 1.463(2) P(1)-N(1) 1.625(3) P(1)-N(3) 1.626(3) P(2)-N(1) 1.552(3) P(2)-N(2) 1.593(3) P(3)-N(3) 1.554(3) P(3)-N(2) 1.582(3) P(4)-N(4) 1.618(3) P(4)-N(6) 1.622(2) P(4)-N(7) 1.628(2) P(4)-N(5) 1.631(3) N(4)-C(1) 1.481(4) N(5)-C(12) 1.462(4) N(5)-C(9) 1.472(4) N(6)-C(8) 1.477(4) N(6)-C(5) 1.478(4) N(7)-C(13) 1.493(4) N(7)-C(16) 1.497(4) C(1)-C(4) 1.529(5) C(1)-C(3) 1.530(4) C(1)-C(2) 1.535(5) C(9)-C(10) 1.480(5) C(10)-C(11) 1.529(5) C(11)-C(12) 1.513(4) C(8)-C(7) 1.521(5) C(7)-C(6) 1.518(6) C(6)-C(5) 1.514(5) C(13)-C(14) 1.523(5) 183 C(14)-C(15) 1.494(5) C(15)-C(16) 1.526(4)

O-P(1)-N(1) 114.90(14) O-P(1)-N(3) 113.83(15) N(1)-P(1)-N(3) 111.91(14) O-P(1)-Cl(1) 106.37(11) N(1)-P(1)-Cl(1) 104.21(12) N(3)-P(1)-Cl(1) 104.36(12) N(1)-P(2)-N(2) 119.95(14) N(1)-P(2)-Cl(3) 108.95(11) N(2)-P(2)-Cl(3) 108.38(11) N(1)-P(2)-Cl(2) 110.94(12) N(2)-P(2)-Cl(2) 106.77(12) Cl(3)-P(2)-Cl(2) 99.97(5) N(3)-P(3)-N(2) 120.76(15) N(3)-P(3)-Cl(4) 108.72(13) N(2)-P(3)-Cl(4) 108.13(12) N(3)-P(3)-Cl(5) 110.45(12) N(2)-P(3)-Cl(5) 107.05(12) Cl(4)-P(3)-Cl(5) 99.65(6) N(4)-P(4)-N(6) 115.17(14) N(4)-P(4)-N(7) 111.66(13) N(6)-P(4)-N(7) 105.10(13) N(4)-P(4)-N(5) 102.92(13) N(6)-P(4)-N(5) 109.45(13) N(7)-P(4)-N(5) 112.77(13) P(2)-N(1)-P(1) 121.20(16) P(3)-N(2)-P(2) 117.76(18) P(3)-N(3)-P(1) 121.42(17) C(1)-N(4)-P(4) 130.7(2) C(12)-N(5)-C(9) 110.9(2) C(12)-N(5)-P(4) 122.7(2) C(9)-N(5)-P(4) 126.4(2) C(8)-N(6)-C(5) 110.5(2) 184 C(8)-N(6)-P(4) 120.5(2) C(5)-N(6)-P(4) 128.6(2) C(13)-N(7)-C(16) 109.9(2) C(13)-N(7)-P(4) 124.4(2) C(16)-N(7)-P(4) 119.09(19) N(4)-C(1)-C(4) 110.0(3) N(4)-C(1)-C(3) 106.0(3) C(4)-C(1)-C(3) 110.0(3) N(4)-C(1)-C(2) 111.3(2) C(4)-C(1)-C(2) 111.0(3) C(3)-C(1)-C(2) 108.4(3) N(5)-C(9)-C(10) 104.0(3) C(9)-C(10)-C(11) 104.1(3) C(12)-C(11)-C(10) 104.5(3) N(5)-C(12)-C(11) 104.8(3) N(6)-C(8)-C(7) 103.7(3) C(6)-C(7)-C(8) 103.9(3) C(5)-C(6)-C(7) 102.2(3) N(6)-C(5)-C(6) 103.1(3) N(7)-C(13)-C(14) 103.3(2) C(15)-C(14)-C(13) 103.6(3) C(14)-C(15)-C(16) 105.5(3) N(7)-C(16)-C(15) 103.8(2) ______Symmetry transformations used to generate equivalent atoms:

185 2 3 - Table 4. Anisotropic displacement parameters (Å x 10 ) for [(PCl2N)2(POClN) ][(t-Bu)NH- + 2 2 2 11 P(N(CH2)4)3 ]. The anisotropic displacement factor exponent takes the form: -2π [ h a* U + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Cl(1) 36(1) 40(1) 39(1) 1(1) 2(1) 6(1) Cl(2) 45(1) 23(1) 26(1) -6(1) 5(1) 0(1) Cl(3) 27(1) 35(1) 34(1) -4(1) -7(1) -2(1) Cl(4) 36(1) 45(1) 29(1) -13(1) 6(1) 1(1) Cl(5) 36(1) 41(1) 26(1) 8(1) -4(1) -2(1) P(1) 26(1) 24(1) 17(1) 2(1) -3(1) -6(1) P(2) 25(1) 20(1) 15(1) -1(1) -1(1) -4(1) P(3) 26(1) 28(1) 14(1) -2(1) -1(1) -4(1) P(4) 15(1) 16(1) 14(1) 0(1) 3(1) 0(1) O 32(1) 28(1) 26(1) 6(1) -5(1) -10(1) N(1) 35(2) 26(1) 16(1) 3(1) -4(1) -9(1) N(2) 32(2) 30(2) 18(1) 1(1) 3(1) -8(1) N(3) 35(2) 32(2) 16(1) -3(1) -2(1) -14(1) N(4) 18(1) 19(1) 15(1) 0(1) 3(1) -4(1) N(5) 15(1) 25(1) 18(1) 4(1) 2(1) 1(1) N(6) 17(1) 15(1) 25(1) -2(1) 3(1) -1(1) N(7) 22(1) 16(1) 10(1) 1(1) 0(1) -2(1) C(1) 24(2) 29(2) 17(2) 0(1) 10(1) -2(1) C(2) 23(2) 34(2) 27(2) -4(1) 8(1) 3(1) C(3) 33(2) 41(2) 18(2) -5(1) 10(1) -6(2) C(4) 36(2) 36(2) 30(2) 5(2) 17(2) -5(2) C(9) 18(2) 48(2) 26(2) 12(2) 1(1) 8(2) C(10) 20(2) 80(3) 44(2) 28(2) 3(2) 4(2) C(11) 23(2) 38(2) 33(2) 7(2) 12(1) 9(2) C(12) 23(2) 60(3) 24(2) 12(2) 8(1) 12(2) C(8) 21(2) 16(2) 55(2) 1(2) 9(2) 3(1) C(7) 35(2) 16(2) 104(4) -3(2) 9(2) -2(2) C(6) 33(2) 40(2) 48(2) -21(2) 7(2) -14(2) C(5) 18(2) 26(2) 36(2) -5(1) 2(1) -5(1) 186 C(13) 28(2) 31(2) 14(1) 2(1) -1(1) -1(1) C(14) 36(2) 43(2) 16(2) 6(2) 2(1) -6(2) C(15) 47(2) 32(2) 27(2) 6(2) 0(2) -9(2) C(16) 29(2) 18(2) 17(1) 3(1) -1(1) -3(1) ______

187 Table 5. Hydrogen coordinates ( x 104) and isotropic displacement parameters (Å2x 10 3) - + for [(PCl2N)2(POClN) ][(t-Bu)NH-P(N(CH2)4)3 ]. ______x y z U(eq) ______

H(1) 5470(40) 350(40) -1110(20) 21 H(2A) 8892 472 -510 41 H(2B) 9342 46 -1422 41 H(2C) 8305 -904 -952 41 H(3A) 6442 -920 -2162 45 H(3B) 7425 -30 -2707 45 H(3C) 5827 447 -2602 45 H(4A) 6804 2660 -2045 49 H(4B) 8416 2185 -2113 49 H(4C) 7982 2715 -1218 49 H(9A) 3473 1847 -1178 37 H(9B) 3460 3189 -603 37 H(10A) 1598 942 -619 58 H(10B) 1180 2511 -578 58 H(11A) 2003 2668 857 37 H(11B) 1437 1136 823 37 H(12A) 4135 1754 1336 42 H(12B) 3670 295 950 42 H(8A) 5617 4164 479 37 H(8B) 5962 4027 -497 37 H(7A) 8139 5043 -206 62 H(7B) 7360 5762 531 62 H(6A) 9636 4460 1025 48 H(6B) 8298 4220 1563 48 H(5A) 9147 2532 227 33 H(5B) 8732 2048 1145 33 H(13A) 6570 1128 1818 29 H(13B) 8045 295 1819 29 H(14A) 6773 -1177 2568 38 188 H(14B) 5264 -778 2023 38 H(15A) 5774 -2745 1380 43 H(15B) 7469 -2429 1480 43 H(16A) 6978 -1734 104 26 H(16B) 5320 -1426 202 26 ______

189 Asymmetric Unit: (C15H9O2)2Si2(CH3)4

190 Disilane: (C15H9O2)2Si2(CH3)4

191 Disordered Solvent

192 Table 1. Crystal data and structure refinement for (C15H9O2)2Si2(CH3)4.

Identification code (C15H9O2)2Si2(CH3)4 Empirical formula C37.50 H30 O4 Si2 Formula weight 600.79 Temperature 100(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/c Unit cell dimensions a = 11.9919(16) Å α= 90°. b = 14.1914(19) Å β= 109.449(2)° c = 19.818(3) Å γ = 90°. Volume 3180.2(8) Å3 Z 4 Density (calculated) 1.255 Mg/m3 Absorption coefficient 0.151 mm-1 F(000) 1260 Crystal size 0.48 x 0.26 x 0.15 mm3 Theta range for data collection 1.80 to 28.31°. Index ranges -15 ≤ h ≤ 15, -18 ≤ k ≤ 18, -25 ≤ l ≤ 26 Reflections collected 28025 Independent reflections 7666 [R(int) = 0.0302] Completeness to theta = 26.30° 100.0 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.9777 and 0.9311 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 7666 / 0 / 410 Goodness-of-fit on F2 1.103 Final R indices [I>2sigma(I)] R1 = 0.0604, wR2 = 0.1521 R indices (all data) R1 = 0.0703, wR2 = 0.1578 Largest diff. peak and hole 0.521 and -0.354 e.Å-3

193 Table 2. Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) ij for (C15H9O2)2Si2(CH3)4. U(eq) is defined as one third of the trace of the orthogonalized U tensor. ______x y z U(eq) ______Si(1) 3236(1) 1804(1) 1912(1) 24(1) Si(2) 3457(1) 180(1) 2056(1) 23(1) O(1) 2113(1) 2003(1) 1112(1) 29(1) O(2) 961(1) 940(1) 1391(1) 36(1) O(3) 4948(1) -61(1) 2475(1) 25(1) O(4) 5062(1) 995(1) 3329(1) 32(1) C(1) 95(2) 1937(1) 375(1) 28(1) C(2) 160(2) 1885(2) -318(1) 31(1) C(3) 1096(2) 1424(2) -478(1) 37(1) C(4) 1113(2) 1410(2) -1162(1) 49(1) C(5) 215(3) 1853(3) -1723(1) 57(1) C(6) -688(2) 2283(2) -1594(1) 51(1) C(7) -772(2) 2311(2) -894(1) 35(1) C(8) -1707(2) 2745(2) -761(1) 35(1) C(9) -1789(2) 2781(2) -77(1) 34(1) C(10) -2754(2) 3228(2) 57(1) 44(1) C(11) -2807(3) 3283(2) 725(2) 62(1) C(12) -1896(3) 2881(3) 1307(2) 69(1) C(13) -964(2) 2442(2) 1204(1) 50(1) C(14) -863(2) 2364(2) 507(1) 32(1) C(15) 1084(2) 1563(2) 1002(1) 28(1) C(16) 2787(2) 2427(2) 2603(1) 39(1) C(17) 4530(2) 2371(2) 1765(1) 37(1) C(18) 2719(2) -369(2) 2641(1) 40(1) C(19) 3137(2) -452(2) 1196(1) 35(1) C(20) 5505(2) 366(1) 3091(1) 23(1) C(21) 6721(2) -2(1) 3477(1) 25(1) C(22) 7612(2) 91(2) 3169(1) 31(1) C(23) 7416(2) 483(2) 2480(1) 39(1) C(24) 8313(2) 568(3) 2208(2) 61(1) 194 C(25) 9474(2) 271(3) 2610(2) 77(1) C(26) 9701(2) -90(3) 3259(2) 68(1) C(27) 8788(2) -208(2) 3577(1) 42(1) C(28) 9013(2) -576(2) 4255(2) 46(1) C(29) 8132(2) -678(2) 4559(1) 38(1) C(30) 8363(3) -1061(2) 5255(2) 52(1) C(31) 7491(3) -1181(2) 5535(2) 57(1) C(32) 6311(3) -916(2) 5142(1) 47(1) C(33) 6051(2) -529(2) 4476(1) 34(1) C(34) 6947(2) -387(1) 4162(1) 28(1) C(35) 4309(6) 8982(6) -343(5) 70(2) C(36) 5280(4) 8511(5) 310(2) 103(2) C(37) 5803(5) 9434(5) 754(4) 57(2) C(38) 5725(3) 10246(4) 542(2) 77(1) C(39) 5204(4) 9346(5) 82(3) 49(2) ______

195 Table 3. Bond lengths [Å] and angles [°] for (C15H9O2)2Si2(CH3)4. ______Si(1)-O(1) 1.7277(15) Si(1)-C(16) 1.854(2) Si(1)-C(17) 1.855(2) Si(1)-Si(2) 2.3263(8) Si(1)-O(4) 3.1465(16) Si(2)-O(3) 1.7363(14) Si(2)-C(18) 1.849(2) Si(2)-C(19) 1.850(2) Si(2)-O(2) 3.0382(16) O(1)-C(15) 1.335(3) O(2)-C(15) 1.213(3) O(3)-C(20) 1.327(2) O(4)-C(20) 1.212(2) C(1)-C(14) 1.399(3) C(1)-C(2) 1.402(3) C(1)-C(15) 1.500(3) C(2)-C(3) 1.423(3) C(2)-C(7) 1.439(3) C(3)-C(4) 1.363(3) C(3)-H(3) 0.9500 C(4)-C(5) 1.413(4) C(4)-H(4) 0.9500 C(5)-C(6) 1.340(5) C(5)-H(5) 0.9500 C(6)-C(7) 1.423(3) C(6)-H(6) 0.9500 C(7)-C(8) 1.380(4) C(8)-C(9) 1.392(3) C(8)-H(8) 0.9500 C(9)-C(10) 1.420(4) C(9)-C(14) 1.437(3) C(10)-C(11) 1.348(4) C(10)-H(10) 0.9500 196 C(11)-C(12) 1.418(4) C(11)-H(11) 0.9500 C(12)-C(13) 1.353(4) C(12)-H(12) 0.9500 C(13)-C(14) 1.430(4) C(13)-H(13) 0.9500 C(16)-H(16A) 0.9800 C(16)-H(16B) 0.9800 C(16)-H(16C) 0.9800 C(17)-H(17A) 0.9800 C(17)-H(17B) 0.9800 C(17)-H(17C) 0.9800 C(18)-H(18A) 0.9800 C(18)-H(18B) 0.9800 C(18)-H(18C) 0.9800 C(19)-H(19A) 0.9800 C(19)-H(19B) 0.9800 C(19)-H(19C) 0.9800 C(20)-C(21) 1.496(3) C(21)-C(22) 1.403(3) C(21)-C(34) 1.403(3) C(22)-C(23) 1.419(4) C(22)-C(27) 1.437(3) C(23)-C(24) 1.360(3) C(23)-H(23) 0.9500 C(24)-C(25) 1.419(5) C(24)-H(24) 0.9500 C(25)-C(26) 1.326(5) C(25)-H(25) 0.9500 C(26)-C(27) 1.443(4) C(26)-H(26) 0.9500 C(27)-C(28) 1.382(4) C(28)-C(29) 1.388(4) C(28)-H(28) 0.9500 C(29)-C(30) 1.421(4) 197 C(29)-C(34) 1.437(3) C(30)-C(31) 1.347(5) C(30)-H(30) 0.9500 C(31)-C(32) 1.420(4) C(31)-H(31) 0.9500 C(32)-C(33) 1.367(3) C(32)-H(32) 0.9500 C(33)-C(34) 1.424(3) C(33)-H(33) 0.9500 C(35)-C(38)#1 1.161(10) C(35)-C(39) 1.235(8) C(35)-C(36) 1.572(11) C(36)-C(39) 1.260(9) C(36)-C(37) 1.586(9) C(37)-C(38) 1.220(9) C(37)-C(39) 1.292(8) C(38)-C(35)#1 1.161(10) C(38)-C(39)#1 1.479(7) C(38)-C(39) 1.572(8) C(39)-C(38)#1 1.479(7) C(39)-C(39)#1 1.920(15)

O(1)-Si(1)-C(16) 105.63(9) O(1)-Si(1)-C(17) 102.88(10) C(16)-Si(1)-C(17) 111.91(12) O(1)-Si(1)-Si(2) 107.26(6) C(16)-Si(1)-Si(2) 115.52(9) C(17)-Si(1)-Si(2) 112.46(8) O(1)-Si(1)-O(4) 167.58(7) C(16)-Si(1)-O(4) 78.60(8) C(17)-Si(1)-O(4) 85.88(8) Si(2)-Si(1)-O(4) 60.79(3) O(3)-Si(2)-C(18) 104.41(9) O(3)-Si(2)-C(19) 102.10(9) C(18)-Si(2)-C(19) 112.21(12) 198 O(3)-Si(2)-Si(1) 108.13(5) C(18)-Si(2)-Si(1) 115.81(9) C(19)-Si(2)-Si(1) 112.78(8) O(3)-Si(2)-O(2) 170.50(6) C(18)-Si(2)-O(2) 79.26(8) C(19)-Si(2)-O(2) 84.24(8) Si(1)-Si(2)-O(2) 62.60(4) C(15)-O(1)-Si(1) 118.00(13) C(15)-O(2)-Si(2) 102.95(13) C(20)-O(3)-Si(2) 118.20(13) C(20)-O(4)-Si(1) 100.77(13) C(14)-C(1)-C(2) 121.47(19) C(14)-C(1)-C(15) 118.06(19) C(2)-C(1)-C(15) 120.4(2) C(1)-C(2)-C(3) 123.2(2) C(1)-C(2)-C(7) 118.3(2) C(3)-C(2)-C(7) 118.5(2) C(4)-C(3)-C(2) 120.2(2) C(4)-C(3)-H(3) 119.9 C(2)-C(3)-H(3) 119.9 C(3)-C(4)-C(5) 121.1(3) C(3)-C(4)-H(4) 119.4 C(5)-C(4)-H(4) 119.4 C(6)-C(5)-C(4) 120.3(2) C(6)-C(5)-H(5) 119.9 C(4)-C(5)-H(5) 119.9 C(5)-C(6)-C(7) 121.5(2) C(5)-C(6)-H(6) 119.2 C(7)-C(6)-H(6) 119.2 C(8)-C(7)-C(6) 121.7(2) C(8)-C(7)-C(2) 120.0(2) C(6)-C(7)-C(2) 118.3(2) C(7)-C(8)-C(9) 121.9(2) C(7)-C(8)-H(8) 119.0 C(9)-C(8)-H(8) 119.0 199 C(8)-C(9)-C(10) 121.6(2) C(8)-C(9)-C(14) 118.8(2) C(10)-C(9)-C(14) 119.6(2) C(11)-C(10)-C(9) 121.1(2) C(11)-C(10)-H(10) 119.4 C(9)-C(10)-H(10) 119.4 C(10)-C(11)-C(12) 120.0(3) C(10)-C(11)-H(11) 120.0 C(12)-C(11)-H(11) 120.0 C(13)-C(12)-C(11) 121.0(3) C(13)-C(12)-H(12) 119.5 C(11)-C(12)-H(12) 119.5 C(12)-C(13)-C(14) 121.4(2) C(12)-C(13)-H(13) 119.3 C(14)-C(13)-H(13) 119.3 C(1)-C(14)-C(13) 123.55(19) C(1)-C(14)-C(9) 119.4(2) C(13)-C(14)-C(9) 117.0(2) O(2)-C(15)-O(1) 122.58(19) O(2)-C(15)-C(1) 123.6(2) O(1)-C(15)-C(1) 113.74(18) Si(1)-C(16)-H(16A) 109.5 Si(1)-C(16)-H(16B) 109.5 H(16A)-C(16)-H(16B) 109.5 Si(1)-C(16)-H(16C) 109.5 H(16A)-C(16)-H(16C) 109.5 H(16B)-C(16)-H(16C) 109.5 Si(1)-C(17)-H(17A) 109.5 Si(1)-C(17)-H(17B) 109.5 H(17A)-C(17)-H(17B) 109.5 Si(1)-C(17)-H(17C) 109.5 H(17A)-C(17)-H(17C) 109.5 H(17B)-C(17)-H(17C) 109.5 Si(2)-C(18)-H(18A) 109.5 Si(2)-C(18)-H(18B) 109.5 200 H(18A)-C(18)-H(18B) 109.5 Si(2)-C(18)-H(18C) 109.5 H(18A)-C(18)-H(18C) 109.5 H(18B)-C(18)-H(18C) 109.5 Si(2)-C(19)-H(19A) 109.5 Si(2)-C(19)-H(19B) 109.5 H(19A)-C(19)-H(19B) 109.5 Si(2)-C(19)-H(19C) 109.5 H(19A)-C(19)-H(19C) 109.5 H(19B)-C(19)-H(19C) 109.5 O(4)-C(20)-O(3) 122.86(18) O(4)-C(20)-C(21) 122.38(18) O(3)-C(20)-C(21) 114.75(17) C(22)-C(21)-C(34) 121.87(19) C(22)-C(21)-C(20) 119.82(19) C(34)-C(21)-C(20) 118.22(18) C(21)-C(22)-C(23) 123.4(2) C(21)-C(22)-C(27) 118.4(2) C(23)-C(22)-C(27) 118.3(2) C(24)-C(23)-C(22) 121.1(3) C(24)-C(23)-H(23) 119.4 C(22)-C(23)-H(23) 119.4 C(23)-C(24)-C(25) 120.5(3) C(23)-C(24)-H(24) 119.7 C(25)-C(24)-H(24) 119.7 C(26)-C(25)-C(24) 120.4(3) C(26)-C(25)-H(25) 119.8 C(24)-C(25)-H(25) 119.8 C(25)-C(26)-C(27) 121.8(3) C(25)-C(26)-H(26) 119.1 C(27)-C(26)-H(26) 119.1 C(28)-C(27)-C(22) 119.7(2) C(28)-C(27)-C(26) 122.5(2) C(22)-C(27)-C(26) 117.8(3) C(27)-C(28)-C(29) 122.1(2) 201 C(27)-C(28)-H(28) 118.9 C(29)-C(28)-H(28) 118.9 C(28)-C(29)-C(30) 122.1(2) C(28)-C(29)-C(34) 119.3(2) C(30)-C(29)-C(34) 118.6(3) C(31)-C(30)-C(29) 121.4(2) C(31)-C(30)-H(30) 119.3 C(29)-C(30)-H(30) 119.3 C(30)-C(31)-C(32) 120.6(3) C(30)-C(31)-H(31) 119.7 C(32)-C(31)-H(31) 119.7 C(33)-C(32)-C(31) 120.0(3) C(33)-C(32)-H(32) 120.0 C(31)-C(32)-H(32) 120.0 C(32)-C(33)-C(34) 121.1(2) C(32)-C(33)-H(33) 119.4 C(34)-C(33)-H(33) 119.4 C(21)-C(34)-C(33) 123.16(19) C(21)-C(34)-C(29) 118.6(2) C(33)-C(34)-C(29) 118.2(2) C(38)#1-C(35)-C(39) 76.1(6) C(38)#1-C(35)-C(36) 127.8(6) C(39)-C(35)-C(36) 51.7(5) C(39)-C(36)-C(35) 50.3(4) C(39)-C(36)-C(37) 52.5(4) C(35)-C(36)-C(37) 98.9(5) C(38)-C(37)-C(39) 77.5(6) C(38)-C(37)-C(36) 128.1(6) C(39)-C(37)-C(36) 50.7(4) C(35)#1-C(38)-C(37) 177.7(6) C(35)#1-C(38)-C(39)#1 54.2(5) C(37)-C(38)-C(39)#1 127.5(5) C(35)#1-C(38)-C(39) 127.4(5) C(37)-C(38)-C(39) 53.3(4) C(39)#1-C(38)-C(39) 77.9(5) 202 C(35)-C(39)-C(36) 78.1(7) C(35)-C(39)-C(37) 143.2(8) C(36)-C(39)-C(37) 76.8(6) C(35)-C(39)-C(38)#1 49.7(5) C(36)-C(39)-C(38)#1 127.7(5) C(37)-C(39)-C(38)#1 146.0(6) C(35)-C(39)-C(38) 145.3(6) C(36)-C(39)-C(38) 126.1(5) C(37)-C(39)-C(38) 49.2(4) C(38)#1-C(39)-C(38) 102.1(5) C(35)-C(39)-C(39)#1 100.1(6) C(36)-C(39)-C(39)#1 162.4(6) C(37)-C(39)-C(39)#1 96.0(6) C(38)#1-C(39)-C(39)#1 53.2(4) C(38)-C(39)-C(39)#1 48.9(3) ______Symmetry transformations used to generate equivalent atoms: #1 -x+1,-y+2,-z

203 2 3 Table 4. Anisotropic displacement parameters (Å x 10 ) for (C15H9O2)2Si2(CH3)4. The anisotropic displacement factor exponent takes the form: -2π2[ h2 a*2U11 + ... + 2 h k a* b* U12 ] ______U11 U22 U33 U23 U13 U12 ______Si(1) 25(1) 24(1) 21(1) 3(1) 4(1) 5(1) Si(2) 16(1) 23(1) 26(1) 4(1) 3(1) 0(1) O(1) 30(1) 29(1) 23(1) 5(1) 0(1) 5(1) O(2) 30(1) 41(1) 33(1) 14(1) 6(1) 9(1) O(3) 16(1) 23(1) 30(1) -1(1) 1(1) 1(1) O(4) 26(1) 34(1) 30(1) -4(1) 2(1) 11(1) C(1) 31(1) 22(1) 22(1) 2(1) -1(1) 0(1) C(2) 30(1) 30(1) 25(1) 4(1) 1(1) -8(1) C(3) 34(1) 46(1) 28(1) 1(1) 6(1) -8(1) C(4) 39(1) 76(2) 33(1) -3(1) 14(1) -15(1) C(5) 43(2) 101(3) 25(1) 7(1) 7(1) -30(2) C(6) 39(1) 77(2) 25(1) 17(1) -5(1) -28(1) C(7) 33(1) 39(1) 25(1) 8(1) -3(1) -17(1) C(8) 30(1) 28(1) 31(1) 11(1) -10(1) -10(1) C(9) 33(1) 21(1) 33(1) 0(1) -9(1) -1(1) C(10) 38(1) 27(1) 48(1) -4(1) -13(1) 12(1) C(11) 51(2) 63(2) 48(2) -24(1) -14(1) 37(2) C(12) 64(2) 91(2) 33(1) -22(2) -9(1) 50(2) C(13) 49(2) 59(2) 27(1) -11(1) -6(1) 31(1) C(14) 34(1) 24(1) 28(1) -3(1) -4(1) 7(1) C(15) 30(1) 28(1) 23(1) 1(1) 5(1) 8(1) C(16) 43(1) 42(1) 27(1) -3(1) 5(1) 19(1) C(17) 37(1) 29(1) 43(1) 7(1) 10(1) -4(1) C(18) 22(1) 51(1) 43(1) 23(1) 6(1) -4(1) C(19) 28(1) 31(1) 39(1) -8(1) 1(1) -2(1) C(20) 17(1) 21(1) 29(1) 2(1) 5(1) 0(1) C(21) 17(1) 18(1) 33(1) -6(1) 0(1) 2(1) C(22) 17(1) 34(1) 39(1) -19(1) 3(1) -1(1) C(23) 26(1) 56(2) 37(1) -20(1) 10(1) -11(1) C(24) 36(1) 108(3) 43(2) -35(2) 19(1) -27(2) 204 C(25) 28(1) 149(4) 58(2) -60(2) 22(1) -23(2) C(26) 17(1) 113(3) 69(2) -61(2) 7(1) -1(1) C(27) 17(1) 53(2) 49(2) -32(1) 1(1) 3(1) C(28) 19(1) 44(1) 57(2) -28(1) -10(1) 13(1) C(29) 29(1) 24(1) 44(1) -9(1) -11(1) 9(1) C(30) 48(2) 29(1) 51(2) 0(1) -19(1) 10(1) C(31) 72(2) 34(1) 41(2) 13(1) -14(1) -2(1) C(32) 54(2) 35(1) 41(1) 8(1) 2(1) -12(1) C(33) 31(1) 26(1) 37(1) 5(1) 1(1) -4(1) C(34) 23(1) 18(1) 34(1) -3(1) -3(1) 2(1) C(35) 48(4) 80(5) 92(5) -55(4) 34(4) -19(3) C(36) 71(3) 171(5) 54(2) -6(3) 5(2) -53(3) C(37) 33(3) 74(4) 58(4) -25(3) 9(3) 11(3) C(38) 54(2) 127(4) 42(2) -16(2) 2(2) -44(2) C(39) 22(2) 97(5) 30(2) -19(3) 12(2) -3(3) ______

205 Table 5. Hydrogen coordinates ( x 104) and isotropic displacement parameters (Å2x 10 3) for (C15H9O2)2Si2(CH3)4. ______x y z U(eq) ______H(3) 1710 1125 -107 44 H(4) 1740 1096 -1262 58 H(5) 252 1847 -2195 69 H(6) -1286 2575 -1978 61 H(8) -2312 3028 -1146 42 H(10) -3372 3493 -331 53 H(11) -3455 3591 805 74 H(12) -1940 2922 1776 83 H(13) -365 2179 1603 60 H(16A) 2578 3080 2452 58 H(16B) 3443 2421 3058 58 H(16C) 2101 2109 2663 58 H(17A) 4683 2069 1360 56 H(17B) 5226 2302 2197 56 H(17C) 4366 3042 1662 56 H(18A) 3097 -974 2818 60 H(18B) 1882 -471 2369 60 H(18C) 2789 49 3047 60 H(19A) 3560 -148 908 53 H(19B) 2284 -434 935 53 H(19C) 3396 -1109 1288 53 H(23) 6645 688 2204 47 H(24) 8161 829 1744 73 H(25) 10092 331 2413 92 H(26) 10487 -277 3522 82 H(28) 9797 -765 4521 55 H(30) 9149 -1235 5529 62 H(31) 7668 -1446 5999 69 H(32) 5702 -1009 5343 56

206 H(33) 5260 -351 4219 40 ______

207