Fundamental Processes in Metal Cluster Chemistry

无机、生物无机和有机金属项目的这一奖项支持加州州立大学北岭分校化学系的Edward Rosenberg博士继续研究配体移动性在金属团簇反应中的作用。特别是，罗森博格将研究氢在氧或氮与金属羰基簇合物系统之间的转移，并调查先前观察到的该反应的动力学同位素效应的来源。他还将研究一些含面封端氮配体的Os和Ru簇合物的取代和加成反应，以阐明立体化学非刚性在该反应中的作用。这些研究将可能为金属表面在催化中的活化机理提供新的见解。质子化的一种机制与观察到的动力学同位素效应一致，但另一种机制是分子间转移。为了确定质子转移在分子内或分子间的程度，我们将研究重氢酸对Ru-羰基的低温质子化反应。在相关工作中，我们将研究一系列的双核Re化合物，以了解团簇的流动性是否会导致对称的氢转移中间体，这是质子隧穿的常见要求。对于立体化学的非刚性研究，一个三核Ru原子簇将与重氮甲烷及其重氢类似物反应，以研究CH在该反应中意外的室温氧化加成以及桥联氢化物的参与(如果有)。

This award in the Inorganic, Bioinorganic, and Organometallic Program supports the continued work of Dr. Edward Rosenberg of the Chemistry Department, California State University at Northridge, for the investigation of the role of ligand mobility in metal cluster reactions. In particular, Rosenberg will study the transfer of hydrogen between oxygen or nitrogen and metal carbonyl cluster systems and investigate the source of the kinetic isotope effect previously observed for this reaction. He will also study substitution and addition reactions of some osmium and ruthenium clusters containing face-capping nitrogen ligands in order to elucidate the role of stereochemical nonrigidity in this reaction. These studies will potentially provide new insights into the mechanism of activation by metal surfaces in catalysis. One mechanism for protonation consistent with the observed kinetic isotope effect is proton tunneling, but an alternative mechanism is intermolecular transfer. Low temperature protonation reactions of ruthenium carbonyls by deuterated acid will be studied in order to determine the extent to which proton transfer is intra- or intermolecular. In related work, a series of dinuclear rhenium compounds will be studied to see if cluster fluxionality can result in a symmetrical hydrogen transfer intermediate, a usual requirement for proton tunneling. For the stereochemical nonrigidity studies, a trinuclear ruthenium cluster will be reacted with diazomethane and its deuterated analog to investigate the unexpected room temperature oxidative addition of CH in this reaction and the involvement, if any, of the bridging hydride.