Stereoregular polyketones from the palladium(II) catalyzed copolymerization of styrenes and carbon monoxide

Chapter One provides an introduction and background to stereoregular polyketones. The early olefin/CO copolymerization catalysts were not well-defined and required high temperatures and pressures. The first metal-catalyzed copolymerization catalysts which were effective under relatively mild conditions appeared in the mid-1980's. Most of the research in stereoregular polymers has been based in poly(;Chapter Two presents results from previous work in styrene/CO copolymerization catalysis from our labs. Cationic Pd(II) monomethyl salts incorporating an achiral bidentate nitrogen ligand and a labile solvent ligand are well-defined complexes which can effect syndiospecific styrene/CO copolymerizations under mild conditions. An associative mechanism for chain transfer during the polymerization is proposed based on kinetic ;The development and study of isospecific styrene/CO copolymerization catalysts is described in Chapter Three. Pd(II) catalysts bearing enantiomerically pure ;The synthesis of an optically active isotactic-b-syndiotactic polyketone and other results from ligand exchange polymerizations is presented in Chapter Four. Rapid exchange between enantiomeric chiral ligands leads to a predominantly syndiotactic copolymer due to cooperativity between chain-end and enantiomorphic site mechanisms of stereocontrol. The intermediate for ligand exchange in several of these systems has been identified by...