Single-site and multiple-site olefin polymerization catalysts: Connections between heterogeneous and homogeneous catalysis

IEC 94

Tobin J. Marks, Chemistry, Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113
Chemisorption upon metal oxide and halide surfaces can dramatically alter the reactivity of many transition metal hydrocarbyls. High activities for olefin polymerization and hydrogenation are two illustrative consequences. This lecture describes chemical and spectroscopic studies using designed organometallic molecules to probe the nature of the molecule-surface coordination chemistry and to understand the reasons for the enhanced reactivity. Such information leads to design rules for the synthesis and spectroscopic/crystallographic/catalytic characterization of functional ion-paired homogeneous phase organometallic models for the surface species. These latter studies lead to not only better understanding of the surface organometallic chemistry and catalysis, but also to better understanding of new classes of "multiple-site" homogeneous olefin polymerization catalysts in which olefin enchainment processes are markedly influenced by cooperative interactions between metal centers. Finally, this information can in turn be used to design next-generation homogeneous and supported catalysts and cocatalysts.