ORGANOMETALLIC AND ORGANIC APPROACHES FOR PRECISION SYNTHESIS AND MODIFICATION OF POLYMERS

Since their discovery, polymers have fundamentally changed our society by serving as valuable materials in applications ranging from transportation to medicine to electronic devices. The physical properties of a polymer are linked to its chemical composition, so development of methods to make or modify the chemical structure of a polymer has direct impact on applications. In this dissertation, efforts towards development of new organometallic methods to precisely synthesize conjugated polymers using dinuclear first-row transition metal complexes and organic approaches to modify or edit the backbones of a commodity polymer to install functional and degradable linkages are described. Chapter 1 presents an overview of the history, synthesis, and application of conjugated polymers and precedents for multinuclear catalysis in both biological and synthetic systems. Chapter 2 explores a dinuclear nickel catalyst with a redox-active naphthyridine diimine ligand for conjugated polymer synthesis. This study establishes dinuclear complexes as effective initiators for chain-growth polymerization of electron-rich and deficient monomers and investigates the mechanism of polymerization—namely, a radical/radical anion-based mechanism. In Chapter 3, a systematic study of both mono- and dinuclear nickel and iron complexes with pyridine diimine based ligands is conducted. Structure-reactivity relationships for the metal complexes in polymerization are elucidated. Notably, chain-growth polymerization for nickel complexes and step-growth polymerization for iron complexes is observed. Chapter 4 defines polymer backbone editing, explores examples of backbone editing in commodity plastic materials, and lays out areas for future growth. In Chapter 5, a tandem C–H functionalization/hydroxyalkyl azide mediated rearrangement of polyethylene is presented. Through this transformation, on-demand insertion of both esters and amides into polyethylene is achieved to generate “polyethylene-like” materials.