Making and Breaking Carbon-Carbon Bonds at Transition Metal Centers

点击翻译按钮获取中文摘要

Dr. Russell P. Hughes, Department of Chemistry, Dartmouth College, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division to determine how transition metals make and break carbon-carbon bonds. To investigate the scope of metal-mediated carbon-carbon cleavage and formation, detailed mechanistic studies will be carried out for the reversible insertion of metal centers into the carbon-carbon bonds of cyclopropenyl rings. As the product of metal-mediated carbon-carbon forming reactions is often dependent on the conformational properties of the metal complex, `sticky` fluorinated substituents will be attached to cyclopentadienyl rings to control conformational properties of metal complexes containing two cyclopentadienyl ligands. This will force the self-assembly of dissymmetric and asymmetric complexes from two achiral cyclopentadienyl ligands. New valence isomers of the metal-cyclopentadienyl fragment and new transition metal complexes containing metal-carbon and metal-heteroatom multiple bonds will be produced through harnessing the steric strain imparted by adjacent tertiary butyl groups on cyclopropenyl and cyclopentadienyl rings to force skeletal rearrangements. Transition metal complexes promote very selective catalytic and stoichiometric transformations of organic compounds. Since many of these reactions involve the activation of normally inert bonds, it is of considerable interest to understand how metal centers make and break bonds between carbon atoms. This study aims toward a fundamental understanding of such processes. The detailed knowledge that will be obtained will permit an increased usage and expansion of metal catalysts and will permit the catalysts to be fine tuned in order to precisely control chemical reactions.