| The development of late metal olefin polymerization catalysts has led to many important advancements over the past decade. The first late metal systems to effectively polymerize olefins to high molecular weight polymers were the cationic α-diimine nickel and palladium catalysts. These catalysts produce polymer with significantly different microstructures than their early metal counterparts. Additionally, the palladium systems will copolymerize ethylene and α-olefins with alkyl acrylates under relatively mild conditions. Such copolymerizations are not possible with early metal catalysts. One drawback, however, is that the relatively high oxophilicity of the cationic metal center limits activity and methyl acrylate incorporation. Therefore, neutral nickel polymerization catalysts were investigated as a less oxophilic alternative to cationic palladium.; Chapter 2 details the synthesis of several 2-anilinotropones, a new class of ligand, and their subsequent coordination chemistry to prepare neutral nickel(II) complexes. The ethylene polymerization activity of these catalysts is described. The reactivity of the 2-anilinotropone neutral nickel(II) catalysts in the presence of polar additives is also reported.; In Chapter 3, the synthesis of a 2-anilinoperinaphthenone ligand and catalyst are described. Similar to Chapter 2, the results from a series of ethylene polymerization experiments are reported. Also included is a brief discussion of polymer branching and catalyst decay.; Chapter 4 encompasses a detailed study of the propagation and decomposition mechanisms for neutral nickel ethylene polymerization catalysts. The synthesis of several new nickel-alkyl complexes is reported. Bulk polymerization results are combined with NMR spectroscopic studies of both the original anilinotropone catalysts and the alkyl intermediates to develop a detailed picture of propagation and catalyst decomposition. |
