Mechanisms and Design in Homogeneous Catalysis

Abstract

The major goal of this research is the determination of structure-activity relationships with respect to the elementary reactions that constitute catalytic alkene polymerization. Three classes of structure-activity relationships pertain to this work: (1) The influence of the nature of the propagating alkyl (secondary, primary, β-substituted) and alkene monomer on the rates and selectivity of propagation, termination, isomerization, hydrogenolysis, etc. Such analyses are possible by direct observation methods (2) Influence of Cp-ligand substituents on fundamental reaction steps by application of direct observation and quenched-flow methods (3) Influence of counterion and solvent polarity on rates and selectivities of elementary steps during polymerization. At this point our rate of progress is limited by a combination of inefficiencies in some data collection modes (particularly quenched-flow studies) and by a relatively narrow range of accessible rates (especially for the NMR methods). Therefore, the bulk of our work concerns the development NMR, mass spectrometric, and chromatographic methods for probing catalytic reactions in a high throughput mode. Although these methods will be applied in the context of alkene polymerization, the NMR and mass spectrometric methods are completely general and will benefit research in all areas of catalysis.