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Russell P. Hughes博士得到化学系无机、生物无机和有机金属项目的支持，研究过渡金属如何形成和破坏碳-碳键。为了研究金属介导的碳-碳解理和形成的范围，将对金属中心可逆插入环丙烯环的碳-碳键进行详细的机制研究。由于金属介导的碳-碳形成反应的产物通常取决于金属配合物的构象性质，“粘性”氟化取代基将附着在环戊二烯环上，以控制含有两个环戊二烯配体的金属配合物的构象性质。这将迫使两个非手性环戊二烯配体的不对称和不对称配合物的自组装。利用相邻叔丁基在环丙烯和环戊二烯环上施加的空间应变迫使骨架重排，将产生新的金属-环戊二烯片段价异构体和含有金属-碳和金属-杂原子多键的新的过渡金属配合物。过渡金属配合物促进有机化合物的选择性催化和化学计量转化。由于这些反应中有许多涉及到通常惰性键的激活，因此了解金属中心如何在碳原子之间形成和破坏键是非常有趣的。本研究旨在对这些过程有一个基本的了解。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，以便精确控制化学反应。