Thermochemical and Reactivity Studies of Basic Transition Metal Complexes

9414242 Angelici爱荷华州州立大学爱荷华州州立大学化学系Robert J. Angelici博士得到化学系无机、生物无机和有机化学项目的支持，研究基本过渡金属络合物的热化学和反应性研究。这个项目的一个主要目标是定量地确定决定金属氢化物络合物中金属中心的碱性或“电子丰度”的因素。量热法测定的质子化率将被测量为一系列的单核络合物的铬，钨，锇，铁，钌，锇，钴铑，铱，以建立贡献的金属及其配体的络合物的碱度。这些电子能将与电化学氧化电位结合，得到键离解能。这些研究将扩展到多核配合物。 许多过渡金属氢化物络合物是用于各种工业和实验室过程的催化剂。这些催化剂的活性与氢从金属转移到反应物物种的容易程度有关。然而，关于决定金属和氢原子之间相互作用强度的因素，可获得的定量信息非常少。在本项目中，将确定一系列金属络合物的金属-氢键强度。这些研究将为理解过渡金属络合物和催化剂的广泛反应性提供基础。

9414242 Angelici Iowa State Univ. Dr. Robert J. Angelici, Chemistry Department, Iowa State University, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division for research into thermochemical and reactivity studies of basic transition metal complexes. A major goal of this project is to quantitatively determine the factors which determine the basicity, or "electron richness", of metal centers in metal-hydride complexes. The calorimetrically determined enthalpies of protonation will be measured for a series of mononuclear complexes of chromium, tungsten, rhenium, iron, ruthenium, osmium, cobalt rhodium, and iridium in order to establish contributions of the metal and its ligands to the basicities of the complexes. These enthalpies will be combined with electrochemical oxidation potentials to give bond dissociation energies. The studies will be extended to polynuclear complexes. Many transition metal hydride complexes are catalysts for a variety of industrial and laboratory processes. The activity of these catalysts is related to the ease with which the hydrogen can move from metal to a reactant species. However, there is very little quantitative information available on the factors which determine the strength of the interaction between a metal and a hydrogen atom. In this project the metal-hydrogen bond strengths will be determined for a range of metal complexes. These studies will provide a basis for understanding a broad range of reactivities of transition metal complexes and catalysts.