Thermochemical and Reactivity Studies of Basic Transition Metal Complexes

该项目属于无机化学的一般领域，也属于过渡金属有机金属化学的特定领域。该项目涉及过渡金属络合物作为碱的倾向，即在溶液中接受来自其他分子的质子。这类质子转移反应通常涉及这些络合物作为均相催化剂或作为合成复杂有机分子的中间体的反应。因此，对它们的碱性进行系统的测量对于了解反应机理和优化用于有机合成的反应条件都是必不可少的。广泛的过渡金属络合物的碱性将通过测量它们的质子化热来确定。配体对络合物碱性的电子和空间效应将通过测定一系列含不同P给体和其他配体的络合物的质子化热值来确定。为了了解金属络合碱性如何影响其他类型的络合反应活性，将测定各种氧化加成反应的速率，并将其与质子化热相关联。由此得到的线性自由能关联有望成为理解广泛范围的复杂反应性的有用指南。在相关研究中，将确定一系列双核和多核金属-金属键化合物转化为H-桥联产物的反应的质子化热。后面的实验将量化配体和金属对金属-金属键的碱性的影响。

This project is in the general area of inorganic chemistry and in the specific area of organometallic chemistry of transition metals. The project is concerned with the tendency of transition metal complexes to act as bases, i.e. to accept protons from other molecules in solution. Such proton transfer reactions are often involved in reactions in which these complexes function either as homogeneous catalysts or as intermediates in the synthesis of complicated organic molecules. Consequently, systematic measurements of their basicities are essential both to understanding reaction mechanisms and to optimizing reaction conditions for using these complexes in organic synthesis. The basicities of a broad range of transition metal complexes will be determined by measuring their heats of protonation. The electronic and steric effects of ligands on complex basicity will be determined by examining values of heat of protonation for a series of complexes with various P-donor and other ligands. In order to understand how metal complex basicities influence other types of complex reactivity, rates of a variety of oxidative-addition reactions will be determined and correlated with heats of protonation. The resulting linear free energy correlations are expected to be useful guides to understanding a broad range of complex reactivity. In related studies heats of protonation will be determined for reactions in which a series of di- and polynuclear metal-metal bonded complexes are converted to H-bridged products. The latter experiments will quantitate the effects of ligands and metals on the basicities of metal-metal bonds.