Date of Award
1995
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
The oxidative addition of E-X bonds (E = Si, Ge, Sn; X = halide) to {dollar}\lbrack\rm PtMe\sb2(diimine)\rbrack{dollar} yields a number of new Pt(IV) complexes containing Pt-E linkages. The complexes {dollar}\lbrack\rm PtXMe\sb2(Me\sb3Si)(diimine)\rbrack{dollar} (X = Br, I) are the first well-characterized examples of Pt(IV)-silyl species. The X-ray structure of {dollar}\lbrack\rm PtIMe\sb2(Me\sb3Si)(bipy)\rbrack{dollar} shows the longest single Pt-I bond reported, and demonstrates the very strong trans influence of the {dollar}\rm Me\sb3Si{dollar} ligand. The X-ray structure of {dollar}\lbrack\rm PtIMe\sb2(Me\sb3Sn)(bipy{dollar}-{dollar}\sp{lcub}t{rcub}\rm bu\sb2)\rbrack{lcub}\cdot{rcub}0.5Me\sb3SnI{lcub}\cdot{rcub}CH\sb2Cl\sb2{dollar} reveals a five coordinate {dollar}\rm Me\sb3SnI{dollar} unit with a novel {dollar}\rm I\cdot\cdot\cdot Sn{dollar}-I interaction.;Many of the Pt-Sn systems studied involve the rapid reversible oxidative addition of Sn-X to Pt(II). Visible spectroscopic studies of the equilibria have been used to establish {dollar}\Delta G\sp\circ\sb{lcub}\rm rxn{rcub},{dollar} which decreases in the series Cl {dollar}>{dollar} Br {dollar}\gg{dollar} I. Variable temperature {dollar}\sp1\rm H{dollar}-NMR spectroscopy has been used to study the kinetics and thermodynamics of the oxidative addition of Sn-X (X = Cl, Br, I) and Ge-Cl bonds to Pt(II) complexes. The influences of solvent, diimine ligand, Group 14 element, and halide on these reactions have been studied, and an {dollar}\rm S\sb{lcub}N{rcub}2{dollar} pathway has been established. Many exchange processes are extremely rapid, with rate constants upwards of {dollar}\rm 10\sp8\ M\sp{lcub}-1{rcub}\ s\sp{lcub}-1{rcub}.{dollar};The decomposition modes of solid Pt(IV) complexes have been studied using TGA and product analysis by {dollar}\sp1\rm H{dollar} NMR spectroscopy. Decomposition occurs by the elimination of {dollar}\rm Me\sb3EX,\ Me\sb4E,{dollar} and {dollar}\rm Me\sb2E.{dollar} The product(s) depend largely on the nature of the Group 14 element and the halide. {dollar}\lbrack\rm PtIMe\sb2(Me\sb3Si)(bipy)\rbrack{dollar} decomposes by the elimination of {dollar}\rm Me\sb4Si,{dollar} and a DSC study of this reaction yields an estimate for the Pt-Si dissociation energy (236 kJ/mol) in the complex.;Halogen abstraction from Pt(IV) complexes yields cationic complexes. {dollar}\lbrack\rm PtMe\sb2(Me\sb2SnCl)(bipy{dollar}-{dollar}\sp{lcub}t{rcub}\rm bu\sb2)\rbrack BF\sb4{dollar} has been structurally characterized and found it to be polymeric with the tin-bound chloro ligand from one complex being very weakly coordinated to the adjacent Pt(IV) centre.
Recommended Citation
Levy, Christopher James, "Reactions Of Group 14-halide Bonds With Dimethylplatinum(ii) Complexes" (1995). Digitized Theses. 2501.
https://ir.lib.uwo.ca/digitizedtheses/2501