Group IV metals in multi-electron reactions and kinetics of 1-hexene polymerization
Abstract
Two investigative projects are presented. The synthesis and characterization of a series of novel complexes; two zirconium complexes and one titanium analog is presented using redox-active ligands. Zirconium was bound to two redox-active ligands in a tetrahedral structure. This complex reacts with molecular oxygen to form a bis-peroxo complex. An octahedral complex is formed where each peroxo occupies one site. The zirconium retains a 4+ oxidation state; the electrons required come from the now oxidized ligands. The η2 bisperoxos are perpendicular to each other. The titanium analog does not react with molecular oxygen to form a peroxo complex. The polymerization kinetics and mechanism of a salan-based zirconium catalyst with 1-hexene were studied. The catalyst features bromo-substituents on the aromatic rings and benzyls as the leaving group. Monomer consumption kinetics, end group and active site analysis were done. Molecular weight distributions and modeling were employed to determine the mechanism. The polymerization was determined to have large chain transfer and little misinsertion. The polymer chains were of similar lengths regardless of the initial conditions.
Degree
Ph.D.
Advisors
Abu-Omar, Purdue University.
Subject Area
Inorganic chemistry|Polymer chemistry
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