Redox-Control Over Ligand Binding: Consequences for Stoichiometric and Catalytic Reactions

Chad A.博士美国西北大学化学系的米尔金是 由无机，生物无机和有机物计划支持， 化学部进行氧化还原活性配体的研究， 过渡金属 这种配体被称为氧化还原可转换的半不稳定配体， 配体（RHL）被设计为产生对所述配体的电化学控制。 空间和电子环境的过渡金属，他们 都被束缚住了 这些影响的程度将被量化， 静电效应和感应效应在结合中的相对重要性 将评估由氧化还原化学引起的亲和力变化。 电化学控制晚期发生的化学转化 过渡金属中心是最终目标。 潜在 这些配合物的应用包括催化烯烃氢化， 不对称烯烃氢化、硅氢化、氢氰化和 甲醇羰基化。 含有金属离子如铑的化合物， 已经发现了含有磷、氧和硫原子的分子 是特别有用的催化剂，这是由于以下事实， 分子的一部分比另一部分结合得更强。 该项目的目标是合成这种新分子， 排序，被称为氧化还原开关半不稳定配体，其中的结合 配体可以通过添加或提取 电子到或从配体本身上的氧化还原活性取代基。 因为配体的氧化态可以很容易地控制 使用电化学，这可以提供额外的元素， 控制催化反应，使催化剂或多或少 取决于氧化态，反应性较低。 水平升高 预计控制将对工业生产产生重要影响。 重要的催化过程。

Dr. Chad A. Mirkin, Department of Chemistry, Northwestern University, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division to perform studies of redox-active ligands with transition metals. The ligands, known as redox-switchable hemilabile ligands (RHLs), are designed to yield electrochemical control over the steric and electronic environment of the transition metals to which they are bound. The magnitude of these effects will be quantified, and the relative importance of electrostatic and inductive effects in binding affinity changes resulting from the redox chemistry will be assessed. Electrochemical control of chemical transformations that occur at late transition metal centers is the ultimate objective. Potential applications for these complexes include catalytic olefin hydrogenation, asymmetric olefin hydrogenation, hydrosilation, hydrocyanation, and methanol carbonylation. Compounds containing metal ions such as rhodium which are bound to molecules containing phosphorus, oxygen and sulfur atoms have been found to be particularly useful catalysts, and this results from the fact that one part of the molecule binds much more strongly than the other part. The objective of this project is to synthesize new molecules of this sort, known as redox-switchable hemilabile ligands, where the binding of the ligand can be controlled by the addition or abstraction of an electron to or from a redox active substituent on the ligand itself. Because the oxidation state of the ligand can be controlled quite easily using electrochemistry, this could provide an additional element of control to the catalytic reactions, making the catalysts either more or less reactive depending on the oxidation state. The increased level of control is expected to have important implications for industrially important catalytic processes.