Principal Research Interests

The research interests of my group are in synthetic and mechanistic organometallic chemistry and catalysis. An important goal of our research efforts is to elucidate the fundamental organometallic chemistry underlying homogenously catalyzed reactions. Stereoselective catalysis is a particular area of interest; we are investigating transition metal complexes as catalysts for enantioselective synthesis and stereospecific polymerization reactions.

Recent advances in homogeneous Ziegler-Natta catalysis have opened up exciting opportunities for the molecular design of polymers of defined architecture. We have recently devised a rational strategy for the synthesis of stereoblock polypropylene utilizing a metallocene catalyst whose structure was designed to interconvert between chiral and achiral coordination geometries on the timescale of the synthesis of a single polymer chain. As the catalyst changes its structure from isospecific to aspecific and back again, a stereoblock polymer results. Stereoblock polypropylene is a rubbery material due to the polymer having a microstructure comprised of alternating isotactic and atactic stereosequences.

We have also developed a novel method for the synthesis of alternating copolymers of ethylene and propylene. For copolymerization, the kinetic selectivity of the catalysts towards the two monomers needs to be controlled in order to control the sequence distribution. These studies combine elements of organometallic chemistry, polymer synthesis, and stereospecific homogeneous catalysis to rationally design new macromolecular structures.