Polymerization and Isomerization of Olefins using Late-Transition Metal Complexes
type: CreativeWork
description: Late-transition metal complexes serve as efficient olefin polymerization catalysts. The mechanism of α-diimine-palladium and nickel catalyzed olefin polymerization is well understood. By understanding the fundamental steps of olefin polymerization, catalysts can be rationally designed to achieve a polymer with desired properties. This dissertation focuses on understanding these fundamental steps in order to design complexes that serve as olefin polymerization and isomerization catalysts. Sandwich-diimine palladium catalysts were used to selectively isomerize 1-olefins to 2-olefins. By activating the palladium catalyst with phenylsilane and NaBArF, a broad range of olefins were isomerized at low catalyst loadings and low temperatures. Mechanistic studies show that regioselectivity is determined by selective displacement of bound internal olefin by a terminal olefin from palladium. Phenanthroline based palladium catalysts were shown to catalyzed a chain running isomerization of olefins. By changing the steric properties of the ligand, but using similar reaction conditions, an alternate, thermodynamic regioselectivity was obtained. A wide range of substrates were isomerized to produce synthetically useful products. The reaction is scalable with very low catalyst loadings. A new monodentate phosphine nickel complex was synthesized and shown to be an efficient olefin polymerization catalyst. The catalyst produced ultrahigh-molecular weight polyethylene and had a turnover frequency that is equivalent to the most active late-transition metal olefin polymerization catalysts. However, a short lifetime was observed and polymerization must be performed at room temperature or below.
abstract: Late-transition metal complexes serve as efficient olefin polymerization catalysts. The mechanism of α-diimine-palladium and nickel catalyzed olefin polymerization is well understood. By understanding the fundamental steps of olefin polymerization, catalysts can be rationally designed to achieve a polymer with desired properties. This dissertation focuses on understanding these fundamental steps in order to design complexes that serve as olefin polymerization and isomerization catalysts. Sandwich-diimine palladium catalysts were used to selectively isomerize 1-olefins to 2-olefins. By activating the palladium catalyst with phenylsilane and NaBArF, a broad range of olefins were isomerized at low catalyst loadings and low temperatures. Mechanistic studies show that regioselectivity is determined by selective displacement of bound internal olefin by a terminal olefin from palladium. Phenanthroline based palladium catalysts were shown to catalyzed a chain running isomerization of olefins. By changing the steric properties of the ligand, but using similar reaction conditions, an alternate, thermodynamic regioselectivity was obtained. A wide range of substrates were isomerized to produce synthetically useful products. The reaction is scalable with very low catalyst loadings. A new monodentate phosphine nickel complex was synthesized and shown to be an efficient olefin polymerization catalyst. The catalyst produced ultrahigh-molecular weight polyethylene and had a turnover frequency that is equivalent to the most active late-transition metal olefin polymerization catalysts. However, a short lifetime was observed and polymerization must be performed at room temperature or below.
author: Kocen, Andrew Lewis 1992-
language: eng
keywords: Organometallic chemistry, Polymer Chemistry, Organic chemistry, Olefin Isomerization, Ultrahigh-molecular weight polyethylene
date published: 2019-08
date modified: 2026-07-24T02:32:54Z
provider: University of Houston
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Houston

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10657/5307