Making and Breaking Carbon-Carbon Bonds at Transition Metal Centers

达特茅斯学院化学系的罗素·P·休斯博士是 由无机，生物无机和有机物计划支持， 化学部门来确定过渡金属是如何形成和破坏的 碳碳键研究金属介导的 碳-碳裂解和形成，详细的机理研究将 进行可逆插入金属中心到 环丙烯基环的碳-碳键。的乘积 金属介导的碳-碳形成反应通常取决于 金属络合物的构象性质，“粘性”氟化 取代基将被连接到双环上以控制 金属配合物的构象性质 配体。这将迫使 两个非手性手性化合物的不对称和不对称配合物 配体。新的价态异构体的金属-β-碎片和 含有金属-碳的新型过渡金属配合物， 金属-杂原子多重键将通过利用 环丙烯基上相邻叔丁基赋予的空间应变 以及迫使骨骼重组的环。 过渡金属络合物促进非常选择性的催化和 有机化合物的化学计量转化。由于许多这些 反应涉及通常惰性键的活化， 相当大的兴趣，了解如何金属中心，使和打破 碳原子之间的键。这项研究旨在从根本上 了解这些过程。详细的知识， 将允许金属催化剂的增加使用和扩展 并且将允许催化剂被微调， 控制化学反应。

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.