The Chemical Structure, Dynamics and Mechanism Program supports Professor Robert H. Grubbs of the California Institute of Technology for the development of a family of catalysts for the inter-conversion of olefins by the olefin metathesis reaction. NSF support for this work began decades ago with the determination of the basic mechanism of the reaction. Today these catalysts find themselves widely used in academic research and in significant commercial applications. These advances include the discovery of new inorganic complexes that show improved activity or selectivity. A number of limitations that remain: the present grant focuses on new catalyst systems, a better understanding of regiochemical and stereochemical issues and the observed low efficiency of the catalysts in the presence of ethylene. These complexes operate by a novel mechanism, and new families of ligands and complexes will be constructed for these catalytic transformations as the mechanism is better understood.
The ruthenium complexes that induce the metathesis of acyclic olefins can also be used for the ring opening polymerization (ROMP) of cyclic olefins. Numerous well-defined polymers have been produced using these complexes as living initiators for the synthesis of block and highly functional polymers. A special class of polymers that is of interest for theoretical reasons and may have interesting applications are polymers without ends-cyclic polymers. A set of ruthenium complexes has been prepared that produce cyclic polymers from cyclic monomers. To be able to test standing theories, polymers that are pure cyclics without linear contaminations are required. A method has been developed that should result in pure cyclics with a range of molecular weights.
In terms of broader impacts and benefits to society, these catalyst systems are currently being used for an array of successful commercial applications. New pharmaceuticals that require the closure of a large ring using these catalysts are being developed and are in clinical trials. A bio-refinery is being constructed that utilizes the complexes for the conversion of seed oils into chemicals and fuels. In the production of new materials, polymers that require the NSF catalysts in their production have been used in the automotive market for a number of years. In addition, new polymer composite materials are being produced for the construction of large-scale mechanical devices.
