Mechanistic Chemistry of Transition Metal Oxygen and Oxo Complexes

爱荷华州立大学化学系的James Espenson博士和Andreja Bakac博士得到了化学系无机、生物无机和有机金属项目的支持，他们的研究是在分子水平上理解氧原子转移。他们将探讨过渡金属氧和氧配合物的氧原子转移反应机理。这些研究包括使用配合物二氧化甲基（MDO）作为原型氧原子受体，无机氧离子和过渡金属氧配合物作为供氧体。动力学和热力学的测定将在马库斯方程的基础上进行，以建立一个氧原子转移反应的尺度。利用氘同位素效应研究氢键对超氧金属配合物稳定性的影响，并研究生物相关铬配合物的超氧和氧离子的化学性质。氧原子从一种金属转移到另一种金属或从金属转移到非金属的化学反应是许多生物和工业过程的基础。然而，由于缺乏对这些过程的基本了解，这一领域的进展目前受到阻碍。在这个项目中，Espenson和Bakac将确定氧在不同原子之间交换的速率和途径，他们将把这些研究与当前描述电子转移反应的理论联系起来。他们将探索与工业和生物相关的氧转移系统。

Dr. James Espenson and Dr. Andreja Bakac of the Department of Chemistry, Iowa State University, are supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division for studies to develop a molecular level understanding of oxygen atom transfer. They will probe the mechanisms of oxygen atom transfer reactions of transition metal oxygen and oxo complexes. The studies include the use of the complex, methylrhenium dioxide (MDO), as a prototype oxygen atom acceptor, and inorganic oxyanions and transition metal oxo complexes as oxygen donors. Kinetic and thermodynamic determinations will be carried out to construct a scale of oxygen atom transfer reactivities on the basis of the Marcus equation. The effects of hydrogen bonding on the stability of superoxometal complexes will be studied using deuterium isotope effects, and the chemistry of superoxo and oxo ions of biologically relevant chromium complexes will be investigated. Chemical reactions in which oxygen atoms are transferred from one metal to another or from metals to non-metals are fundamental to many biological and industrial processes. However, advances in this area are currently hindered by the lack of a fundamental understanding of these processes. In this project, Espenson and Bakac will determine the rates and pathways by which oxygen is exchanged between various atoms, and they will relate these studies to the current theory which describes electron transfer reactions. They will explore oxygen transfer systems with industrial and biological relevance.