Lewis Acids: Electron Transfer Reagents

点击翻译按钮获取中文摘要

With support from the Organic Dynamics Program, Dr. Jensen will study metal ion catalyzed reactions of organic substances with water as a means to determine the reactive behavior of metal ions in various states of complexation. Metal ions play a vital role in the chemical processes essential to our quality of life, both from an industrial/economic viewpoint as well as from a biological perspective. Information gained via exploration of the dependence of metal ion reactivity on the state of metal complexation is expected to have application to environmental problems (e.g., problems related to detoxification of organomercurials in the environment) and to the development of new chemical transformations. It has been shown that the ability of mercury(II) ions to promote hydrolysis of O,S-acetals is greatly diminished when the reaction is performed in the presence of anions that are capable of complexing this ion. The project seeks to clarify the role of the heavy metal ion in such reactions, i.e., does the metal simply function as a Lewis acid, or does the reaction with, e.g., O,S-acetals involve oxidation of sulfur via electron transfer to the heavy metal ion? The effect of changing the hydrolysis-promoting reagent from a Lewis acid reagent to an electron transfer reagent will be probed via kinetic studies that involve high oxidation state metallocomplexes of a variety of transition metals. Fast reaction kinetic (i.e., stopped-flow) techniques will be utilized to detect build-up of oxidized sulfur species that is postulated to occur prior to decomposition of the O,S-acetal in electron transfer mediated processes.