Synthesis of polymers with controlled structures using ROMP initiators

Abstract

Ruthenium based olefin metathesis catalysts have provided new routes to olefins that appear in a variety of structures. Their functional group tolerance and ease of use allow their application in the synthesis of multifunctional bioactive mols. that are being explored as pharmaceutical agents. The same systems are also useful for the synthesis of an array of new materials from multifunctional polymers to supramol. systems. Of particular interest are brush polymer systems that phase sep. into ordered structures. The long-range order of these periodic structures is controlled by the selection and ordering of the block components. We are exploring the factors that control the spacing and attempting to develop a detailed picture of the phase sepn. process. The catalysts can also be used to construct telechelic polymers and in the prodn. of composite materials. Underlying these developments has been the discovery of active catalysts with controlled selectivity through the synthesis of new ligands that control the geometry of the intermediate carbene and metallacycle complexes. A recent finding has been a ligand system that controls the geometry of the double bond that is formed in the metathesis process. A particularly efficient catalyst that will dimerize olefins to the Z geometry in high yields has been developed. These systems also generate a family of high Z polymers with controlled tacticity.