Heterolytic Bond Activation by First Row Transition Metals

该奖项属于无机、生物无机和有机金属化学项目，用于支持德克萨斯 A&M 大学化学系的 Marcetta Y. Darensbourg 博士关于第一排过渡金属的异解键活化的研究。 将开展三个项目：（1）配体工程，通过邻近的第一行过渡金属激活 C-H 异解键断裂； (2)硫醇镍活化二氧化硫生成硫酸盐的机理； (3)低价镍配合物中的均裂C-S键断裂，其中Ni-H酸性由配体结构控制。 在第一项研究中，刚性螯合和四齿配体将稳定金属（Co、Fe 或 Ni），并使 C-H 键位于靠近金属中心的位置，以促进其活化。 在第二项研究中，镍配合物将用于促进二氧化硫与分子氧的不寻常反应，其中二氧化硫直接转化为阴离子硫酸盐，而不形成金属结合的硫酸盐。 在第三个项目中，还将研究二氧化碳的活化，并测定高度还原物质中Ni-H的酸度。 在受控条件下的键断裂对于许多重要的化学反应至关重要。 在该奖项支持下研究的所有反应中，将控制金属相对于被破坏的键的位置，以研究如何使用金属来定位其他原子进行反应。 回答这个问题对于理解许多生物酶反应和开发新的工业催化剂非常重要。 此外，寻找经济的氧化二氧化硫的方法对于减少污染至关重要，从而增加了了解二氧化硫与氧气反应细节的意义。

This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research by Dr. Marcetta Y. Darensbourg of the Department of Chemistry, Texas A&M University, on hetrolytic bond activation by first row transition metals. Three projects will be pursued: (1) ligand engineering to activate C-H heterolytic bond cleavage by proximate first row transition metals; (2) mechanism of nickel-thiolate activation of sulfur dioxide to sulfate; (3) homolytic C-S bond cleavage in low-valent nickel complexes in which Ni-H acidity is controlled by ligand structure. In the first study, rigid chelating and tetreadentate ligands will stabilize the metals (Co, Fe, or Ni) and enable a C-H bond to be positioned close to the metal center to promote its activation. In the second investigation, nickel complexes will be used to promote reaction of sulfur dioxide with dioxygen in an unusual reaction in which sulfur dioxide is converted directly to anionic sulfate without formation of a metal-bound sulfate. In the third project, activation of carbon dioxide will also be studied, and the acidity of Ni-H in highly reduced species will be determined. Bond breakage under controlled conditions is critical in many essential chemical reactions. In all the reactions studied with the support of this award, the position of the metal with respect to bonds to be broken will be controlled to order to investiate how to use metals to position other atoms for reaction. Answering this question is important for understanding many biological enzyme reactions and for developing new industrial catalysts. In addition, finding economic means to oxidize sulfur dioxide is vital for pollution abatement, thus adding to the significance of understanding the details of reaction of sulfur dioxide and oxygen.