Fundamental studies of group 10 metal ethylene oligomerization and polymerization catalysts.

摘要

This thesis describes the exploration of new catalysts for the insertion polymerization and oligomerization of ethylene, as well as the mechanistic study of a key step in the polymerization catalyzed by palladium alkyl complexes that contain ortho-phosphino-arenesulfonate ligands ([PO] -).;Chapter One provides an introduction to the synthesis of functionalized polyethylene.;Chapter Two describes the synthesis and characterization of the base-free [2-PR2-4-Me-benzenesulfonate]Ni(benzyl) complexes (R = 2-OMe-Ph (4a), Cy (4b)), and the homopolymerization of ethylene using these catalysts.;Chapter Three describes the chemistry of palladium alkyl complexes that incorporate the NHC-sulfonate ligand N-(2,6-diisopropylphenyl)- N'-2-benzenesulfonate-NHC ([C-O]-, NHC = cyclo-CNCH2CH2N).;Chapter Four focuses on the mechanism of cis/trans isomerization of [PO]PdMe(2,6-lutidine) ([PO]- = 2-P(2-OMe-Ph)2-4-Me-benzenesulfonate) complex. Three possible mechanisms for this isomerization are proposed, including those via a tetrahedral transition state, a 5-coordinate transition state, and a 3-coordinate zwitterionic intermediate. Kinetics, structure activity correlations and solvent effects show that this isomerization occurs via competing lutidine-catalyzed and unimolecular mechanisms, and that the latter involves sulfonate dissociation to produce a configurationally labile 3-coordinate intermediate.