Chan, Ka Po. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Abstracts in English and Chinese. / Table of contents --- p.vi / Acknowledgements --- p.i / Abstract --- p.ii / 摘要 --- p.iv / List of Compounds Synthesized --- p.xi / Abbreviation --- p.xii / Chapter Chapter 1 --- Synthesis and characterization of pyrazyl-Iinked bis(phosphoranoimido) main group 14 and 13 metal complexes / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.1.1 --- A general review of phosphoranoimine ligands --- p.1 / Chapter 1.1.2 --- A general review of group 14 metal complexes containing phosphoranoimine ligands --- p.8 / Chapter 1.1.3 --- A general review of group 13 metal complexes containing phosphoranoimine ligands --- p.10 / Chapter 1.2 --- Objectives --- p.12 / Chapter 1.3 --- Results and Discussion --- p.14 / Chapter 1.3.1.1 --- Synthesis of pyrazyl-Iinked bis(phosphoranoimine) (Me3SiN=PPr'2CH2)2C4H2N2-2，3 (35) and dilithium compound [{Li(THF)2(Me3SiNPPr'2CH)}2C4H2N2-2，3}] (36) --- p.14 / Chapter 1.3.1.2 --- Spectroscopic properties of 35 and 36 --- p.15 / Chapter 1.3.1.3 --- "Molecular structure of [{Li(THF)2(Me3SiNPPr'2CH)}2C4H2N2-2,3}] (36)" --- p.16 / Chapter 1.3.2.1 --- Synthesis of stannacyclopentane [Sn{C(H)(Pr')2P=N(SiMe3)}2C4H2N2-2，3] (37) and chlorostannylene [{Sncl(Me3SiNPPr'2CH)}2C4H2N2-2，3] (38) --- p.20 / Chapter 1.3.2.2 --- Spectroscopic properties of 37 and 38 --- p.20 / Chapter 1.3.2.3 --- "Molecular structures of [Sn{C(H)(Pr')2P=N(SiMe3)}2C4H2N2-2,3] (37) and [{SnCl(Me3SiNPPr'2CH)}2C4H2N2-2,3] (38)" --- p.22 / Chapter 1.3.3.1 --- "Synthesis of asymmetric lead(II) enamido and chloro compound [{PbCl(Me3SiNPPr'2CH)}C4H2Nr2，3-(CHPPr'2Me3SiN)Pb(Me3SiN PPr'2C)C4H2N2-2,3-(CHPr'2P=NSiMe3)] (39)" --- p.28 / Chapter 1.3.3.2 --- Spectroscopic properties of 39 --- p.30 / Chapter 1.3.3.3 --- "Molecular structure of [{Pbcl(Me3SiNPPr'2CH)}C4H2N2-2,3-(CHPPr'2Me3SiN)Pb(Me3SiN PPr'2C)C4H2N2-2，3-(CHPr'2P=NSiMe3)] (39)" --- p.30 / Chapter 1.3.4.1 --- Synthesis of polymeric dilithiated cyclic germylene [Ge{C(Pr')2PN(SiMe3)Li(THF)}2(02C4H8)C4H2N2-2，3] (40) --- p.35 / Chapter 1.3.4.2 --- Spectroscopic properties of 40 --- p.37 / Chapter 1.3.4.3 --- Molecular structure of [Ge{C(Pr')2PN(SiMe3)Li(THF)}2(02C4H8)C4H2N2-2，3] (40) --- p.37 / Chapter 1.3.5.1 --- "Synthesis of bis(trimethylsilyl)amido metal compounds [{Sn{N(SiMe3)2}(Me3SiNPPr'2CH)}2C4H2N2-2,3] (41) and [{Pb{N(SiMe3)2}(Me3SiNPPr'2CH)} C4H2N2-2，3{Pb(CHPr'2P= NSiMe3){N(SiMe3)2}}](42)" --- p.41 / Chapter 1.3.5.2 --- Spectroscopic properties of 41 and 42 --- p.42 / Chapter 1.3.5.3 --- Molecular structures of [{Sn{N(SiMe3)2}(Me3SiNPPr'2CH)}2C4H2N2-2，3] (41) and [{Pb{N(SiMe3)2}(Me3SiNPPr'2CH)}C4H2Nr2，3{Pb(CHPr'2P= NSiMe3){N(SiMe3)2}}](42) --- p.43 / Chapter 1.3.6.1 --- "Synthesis of pyrazyl-linked bis(phosphoranoimido) group 13 metal compounds [{MCl2(Me3SiNPPr'2CH)}2C4H2N2-2，3] (M=A1 (43)， Ga (44)) and [{AlMe2(Me3SiNPPr'2CH)}2C4H2N2-2,3] (45)" --- p.49 / Chapter 1.3.6.2 --- "Spectroscopic properties of 43, 44 and 45" --- p.50 / Chapter 1.3.6.3 --- "Molecular structures of[{MCl2(Me3SiNPPr'2CH)}2C4H2N2-2,3] (M=A1 (43), Ga (44)) and [{AlMe2(Me3SiNPPr'2CH)}2C4H2N2-2,3] (45)" --- p.50 / Chapter 1.4 --- Experimental Section --- p.57 / Chapter 1.5 --- References for chapter 1 --- p.67 / Chapter Chapter 2 --- Reactivity of pyrazyl-Iinked bis(phosphoranoimido) heteroleptic stannylenes / Chapter 2.1 --- Introduction --- p.73 / Chapter 2.1.1 --- A general review of heteroleptic stannylenes --- p.73 / Chapter 2.2 --- Objectives --- p.80 / Chapter 2.3 --- Results and Discussion --- p.81 / Chapter 2.3.1.1 --- "Reaction of 38 with sodium cyclopentadienide: synthesis of [{Sn(η1-C5H5)(Me3SiNPPr'2CH)}2C4H2N2-2,3] (70)" --- p.81 / Chapter 2.3.1.2 --- Spectroscopic properties of 70 --- p.81 / Chapter 2.3.1.3 --- "Molecular structure of [{Sn(η1-C5H5)(Me3SiNPPr'2CH)}2C4H2N2-2,3] (70)" --- p.83 / Chapter 2.3.2.1 --- "Reaction of 41 with 3,5-di-tert-butyl-o-benzoquinone: synthesis of [{Sn{0(2,4-di-Bu1-C6H2)0}{N(SiMe3)2}(Me3SiNPPr'2CH)}2 C4H2N2-2,3] (71)" --- p.86 / Chapter 2.3.2.2 --- Spectroscopic properties of 71 --- p.87 / Chapter 2.3.2.3 --- "Molecular structure of [{Sn{0(2´ة4-di-Bu'-C6H2)0}{N(SiMe3)2}(Me3SiNPPr'2CH)}2 C4H2N2-2,3] (71)" --- p.88 / Chapter 2.4 --- Experimental Section --- p.91 / Chapter 2.5 --- References for chapter 2 --- p.93 / Chapter Chapter 3 --- "Synthesis, characterization and catalytic study of pyrazyl-linked bis(phosphoranoimido) group 4 early transition metal complexes" / Chapter 3.1 --- Introduction --- p.96 / Chapter 3.1.1 --- A general review of group 4 early transition metal complexes containing phosphoranoimine ligands --- p.96 / Chapter 3.1.2 --- A general review of olefin polymerization with group 4 metallocene catalysts --- p.99 / Chapter 3.2 --- Results and Discussion --- p.101 / Chapter 3.2.1.1 --- "Synthesis and characterization of pyrazyl-linked bis(phosphoranoimido)chloro group 4 transition metal compounds [{MCl3(Me3SiNPPr'2CH)}2C4H2N2-2,3] [M = Zr (72)，Hf (73)]" --- p.101 / Chapter 3.2.1.2 --- Spectroscopic properties of 72 and 73 --- p.101 / Chapter 3.2.1.3 --- "Molecular Structure of [{HfCl3(Me3SiNPPr'2CH)}2C4H2N2-2,3] (73)" --- p.102 / Chapter 3.2.2.1 --- "Synthesis and characterization of pyrazyl-linked bis(phosphoranoimido)amido group 4 transition metal compounds [μ-M(NMe2)2(Me3SiNPPr'2CH)C4H2N2-2,3(CHPPr'2NSiMe3) M(NMe2)3]2 [M = Zr (74), Hf (75)]" --- p.105 / Chapter 3.2.2.2 --- Spectroscopic properties of 74 and 75 --- p.106 / Chapter 3.2.2.3 --- "Molecular Structure of [μ-Zr(NMe2)2(Me3SiNPPr'2CH)C4H2N2- 2,3(CHPPr'2NSiMe3)Zr(NMe2)3]2 (74)" --- p.107 / Chapter 3.2.3.1 --- Catalytic studies of compounds 72-75 on ethylene polymerization --- p.110 / Chapter 3.3 --- Experimental Section --- p.112 / Chapter 3.4 --- References for chapter 3 --- p.116 / Appendix I / Chapter A. --- General Procedures --- p.118 / Chapter B. --- Spectroscopic and physical measurements --- p.118 / Appendix II / Table A.1. Selected crystallographic data for compounds 36-39 --- p.121 / Table A.2. Selected crystallographic data for compounds 40-43 --- p.122 / "Table A.3. Selected crystallographic data for compounds 44, 45, 70 and 71" --- p.123 / Table A.4. Selected crystallographic data for compounds 73 and 74 --- p.124

The first example of an N,N'-chelated [beta]-diketiminato phosphenium salt has been isolated by careful tuning of both the ligand architecture and the electronic characteristics of the phosphorus containing moiety. Using a two-electron reduction approach, the first example of a phosphinidene valence isomer has been isolated and structurally characterized. The mechanism of formation of this valence isomer was elucidated via Density Functional Theory (DFT) calculations. These calculations revealed that the formation of this valence isomer involves the intermediacy of a triplet diradical. In turn, the triplet diradical decays by two further steps to generate the observed product. A cationic phosphinous acid has been prepared via the hydrolysis of a cationic phosphenium complex in basic solution. DFT calculations reveals that the introduction of a positive charge stabilizes the phosphinous acid form. Two N,C-bonded phosphenium cation salts have also been obtained, the crystal structures of which reveal that the formation of these compounds involves C-H activation of a methyl group on the [beta]-diketiminate ligand. Three synthetic methods, namely halide abstraction, aluminum/boron halide exchange process and salt metathesis, have been explored for the preparation of boron cations supported by [beta]-diketiminate ligands. The first structurally characterized boron cation supported by a [beta]-diketiminate ligand has been isolated as its [Al₂Cl₇]⁻ salt. A Ga-Fe organometallic complex supported by a [beta]-diketiminate ligand has also been synthesized via salt metathesis reaction and fully characterized. Finally, several bisamidinate supported boron complexes have been synthesized and structurally characterized. Such complexes may have applications as bifunctional catalysts or as building blocks for novel polymers.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.Sc.) -- Memorial University of Newfoundland. 1973. / Typescript. Bibliography : leaves 132-136. Also available online.

The design of catalysts for transition metal-mediated reactions is an active field in chemistry in the 21st century. It has been well recognised that ligands employed in these processes have a significant impact on the outcome of the reactions. The design and application of ligands in homogeneous catalysis reactions were the overarching aims of this project. Two areas were explored in this project, on the ligand synthesis side: 1. The use of directed ortho metallation (DoM) technology to synthesise unsymmetrical phosphines. 2. The synthesis of sterically hindered phosphines and their application to transition metal-mediated reactions. For the first sub-project, a range of N,N-dialkyl-diphenylphosphinic amides was synthesised in near quantitative yields. Deprotonation with s-BuLi and quenching the anion formed in the reaction with a range of electrophiles resulted in the desired ortho-substituted products in good yields. Differentiation of the second aromatic ring was possible, if the isolated mono-substituted products were used in further DoM reactions as starting materials. This methodology provided a range of highly substituted unsymmetrical phosphinic amides. Incorporation of other directing groups can change the selectivity of subsequent DoM reactions providing efficient routes to 2,2’ and 2,6-disubstituted products. Hydrolysis of the phosphinic amide moiety to the phosphinic acid with aqueous HCl, chlorination (SOCl2) and reaction of the acid chloride with a range of Grignard reagents provided an efficient method for the conversion of the phosphinic amide into a P-chirogenic but racemic phosphine oxide. Known methodology can convert this phosphine oxide into a phosphine that can be applied to transition metal catalysed reactions. This methodology provides an effective method for the synthesis of highly functionalised unsymmetrical phosphines. The approach facilitated substantial modifications to the ligand, which allows for efficient tailoring thereof for the metal-mediated reaction in which it is to be used. In the second sub-project, the DoM reaction was again employed but with (diaryl or dialkyl) phosphines as electrophilic quenches, resulting in the isolation of sterically hindered phosphines. Comparison between the ligands was made using the palladium-catalysed Suzuki reactions (catalytic approaches), Vaska type complexes (electronic effects) and phosphine selenium coupling constants (stereo-electronic effects). It was concluded that steric bulk and electronic characteristics affect the activity of catalysts formed from the ligands of this study, in line with the literature. The ligands were successfully applied to the palladium-catalysed Suzuki reaction using strongly deactivated aryl bromides and also some activated aryl chlorides as substrates at low (0.1% Pd) catalyst loadings. Significant improvements in catalytic activity were observed as the project progressed, using a structure-activity study as a guide. / Prof. D.B.G. Williams

M.Sc. / The objective of the project described in this dissertation was the preparation of a range of bulky electron-rich phosphine ligands making use of the directed ortho metallation (DoM) methodology developed in our labs. These ligands would then be employed in the Suzuki and Heck reactions of aryl bromides and aryl chlorides. A range of phosphinic amides were synthesised with various structural differences. These phosphinic amides all showed high activity in the DoM reaction when using TMSCl and MeI as electrophiles, by successfully incorporating TMS and Me groups in the ortho-positions of these phosphinic amide systems. A phosphonic amide was also synthesised and used in the DoM reaction, and also successfully incorporated TMS and Me in the ortho-position of this system. The success of these reactions was encouraging and provided a route to incorporate a phosphine on the ortho-position of these phosphinic amide and phosphonic amide systems by using a range of phosphine electrophiles Ar2PCl. The route was versatile and various electrophiles were used to prepare phosphine ligands with varying electronic and steric properties. These electrophiles were prepared from PCl3 and the corresponding Grignard reagent. Vaska-type complexes and phosphine selenium coupling constants were used to determine the electronic and stereo-electronic characteristics of the prepared ligands. The phosphine ligands prepared in this project making use of our DoM methodology were tested in the Suzuki cross-coupling reactions and Heck arylation reactions of aryl bromides and aryl chlorides and showed good reactivity with most of the substrates used. An advantage of the ligands prepared is that these ligands are oxidatively and hydrolytically stable

M.Sc. / The main objective of the research described in this dissertation was to prepare several logical series of ligands, being variously substituted at different positions of the aryl ring attached to the P atom. These ligands were evaluated by several techniques including 31P NMR shift measurements, 31P-77Se NMR coupling constant measurements, CO stretching frequency measurements in rhodium(I) Vaska-type complexes of the ligands, application of the ligands in the Rh-catalysed hydroformylation reaction, X-ray studies on single crystals of some of the ligands and computational studies all with the view to establish if phosphorus atoms in arylphosphines could be used as a handle to probe steric and electronic effects of aromatic systems. A series of triarylphosphine ligands containing either ester, fluoro, nitrile, tolyl or a combination of functional groups was prepared by reacting Grignard- or organolithium reagents with P-Cl reagents. The results of this aspect of the work showed that, under the right reaction conditions, these organometal reagents can tolerate certain functional groups. On evaluation of these ligands with the different techniques described above it was found that: 31P NMR shift measurements cannot be used in correlations with the data from the other methods of evaluation used in this study, 31P-77Se coupling constant measurements and CO stretching frequency measurements in rhodium(I) Vaska-type complexes of the ligands can be correlated to a relatively good extent with Rhcatalysed hydroformylation reaction results (provided that ortho-substituted phosphine data are disregarded), 31P-77Se NMR coupling constant measurements and CO stretching frequency measurements in rhodium(I) Vaska-type complexes of the ligands correlated well with computational studies, and finally, computational studies at the level of theory used in this dissertation also correlate quite well with the Rh-catalysed hydroformylation reaction results. In all it was found from this study that the phosphorus atom in arylphosphines can be used as a handle to probe the electronic and steric effects of aromatic systems, and that the most versatile method of ligand evaluation were the 31P-77Se coupling constant measurements and CO stretching frequency measurements in rhodium(I) Vaska-type complexes.

No description available.

Conformations of phenyl and alkyl substituted phosphines were studied by using an empirical computer program, CAMSEQ. The computer program employs potential energy functions for calculating non-bonded interactions. The three potential energy functions employed are: steric interactions, represented by Lennard-Jones 6-12 potentials; electrostatic interactions, computed from a Coulomb's Law function; and torsional barriers, approximated by a two-term cosine function. P-C and C-C torsional functions were parameterized for a variety of phosphorus and carbon substituents from published experimental data. Phenyl and alkyl substituent conformations as affected by length, Position and number of alkyl chain substituents are described and related to effective sizes of the phosphines.Ball State UniversityMuncie, IN 47306

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 135-142). Also available in electronic version. Access restricted to campus users.