Synthetic, Structural and Mechanistic Investigations of New Derivatives of the Early Transition Metals Having Reactive Ligands

John E.美国加州化学研究所化学系 技术，由无机，生物无机和 化学系有机化学专业， 前过渡金属结构和机理研究 具有反应性配体的络合物。一系列刘易斯酸性基团4和5 含有相邻刘易斯碱位点的金属络合物， 将制备配位的配体。由于两性的性质， 这些化合物活化H-X σ键的新途径将 金属的氧化状态可以通过 新反应类型的机理将是 确定和比较，将与更常见的弯曲三明治 金属的类似物。 基于过渡金属化合物的催化剂被广泛用于催化剂的制备中。 化学工业和有机过渡的重要新发展 金属化学通常集中在开发新的催化剂或 现有的优化。本研究的目的是 制备和结构表征新型的前过渡金属 含有与金属相连的“非无辜”基团的化合物。这些 被称为配体的基团将带有反应性位点， 过渡金属的行为以新颖的、系统的方式改变。 新化合物应该会激活与氢有关的键， 催化烯烃聚合。最终目标是开发催化剂 选择性地转化容易获得的物质， 碳氢化合物、水和氨转化为更有价值的产品。

Dr. John E. Bercaw, Chemistry Department, California Institute of Technology, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division for synthetic, structural, and mechanistic investigations of early transition metal complexes having reactive ligands. A series of Lewis acidic group 4 and 5 metal complexes which contain adjacent Lewis base sites contained in coordinated ligands will be prepared. Because of the amphoteric nature of these compounds new pathways for the activation of H-X sigma bonds will be opened and the oxidation state of the metal can be adjusted through the control of pH. The mechanisms of new reaction types will be determined and comparisons will be made with the more usual bent sandwich analogues of the metals. Catalysts based on transition metal compounds are used extensively in the chemical industry and important new developments in organo-transition metal chemistry often center on the development of new catalysts or on the optimization of existing ones. The objective of this research is to prepare and structurally characterize new types of early transition-metal compounds that contain `non-innocent` groups attached to the metal. These groups, called ligands, will bear reactive sites that will allow the behavior of the transition metal to be altered in novel, systematic ways. The new compounds should activate bonds involving hydrogen and may catalyze olefin polymerization. The ultimate goal is to develop catalysts to selectively transform readily available substances such as hydrocarbons, water, and ammonia into more valuable products.