Making and Breaking Carbon-Carbon Bonds at Transition Metal Centers

过渡金属中心碳-碳键的形成和断裂

• 批准号: 9627882
• 负责人: Russell Hughes
• 金额: $ 30万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-15 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9627882&HistoricalAwards=false
• 关键词: Making; Breaking; Carbon; Bonds; Transition

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.

达特茅斯学院化学系的罗素·休斯（Russell P. Hughes）博士得到了化学部的无机，生物无机和有机金属计划的支持，以确定过渡金属如何制造和破坏碳碳债券。为了研究金属介导的碳碳裂解和形成的范围，将进行详细的机械研究，以将金属中心可逆地插入环丙基苯基环的碳碳键中。由于金属介导的碳碳形成反应的乘积通常取决于金属络合物的构象性能，因此“粘性”氟化取代基将附着在环戊二烯基环上，以控制含有两个环戊二烯基配体的金属络合物的构象特性。这将迫使来自两个精神环戊二烯基配体的非对称和不对称复合物的自组装。金属环戊二烯基片段的新价异构体和含有金属碳和金属杂色多种键的新的过渡金属络合物将通过在环丙基苯基和环戊二烯基上施加的邻接第三丁二丁基基团赋予的空间菌株来产生，从而产生。 过渡金属复合物可促进有机化合物的非常选择性的催化和化学计量变化。由于这些反应中的许多反应涉及正常惰性键的激活，因此了解金属中心如何在碳原子之间建立和破坏键是很大的兴趣。这项研究旨在对此类过程进行基本理解。将获得的详细知识将允许增加金属催化剂的使用和扩展，并允许对催化剂进行微调以精确控制化学反应。