Heterolytic Bond Activation by First Row Transition Metals

这个奖项在无机，生物无机和有机化学计划支持研究博士Marcetta Y。 Darensbourg，德克萨斯A M大学化学系，关于第一行过渡金属的异裂键活化。 三个项目将继续进行：（1）配体工程，以激活C-H异裂键断裂的第一行过渡金属;（2）镍-硫醇盐活化二氧化硫硫酸盐的机理;（3）低价镍配合物中的均裂C-S键断裂，其中Ni-H酸度由配体结构控制。 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键靠近金属中心以促进其活化。 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反应，这是一种不寻常的反应，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，并将确定高度还原物种中Ni-H的酸度。 在受控条件下的键断裂在许多基本化学反应中是关键的。 在该奖项支持下研究的所有反应中，金属相对于要断裂的键的位置将被控制，以研究如何使用金属来定位其他原子进行反应。 阐明这一问题对于理解许多生物酶反应和开发新的工业催化剂具有重要意义。 此外，寻找经济的方法来氧化二氧化硫是至关重要的污染治理，从而增加了了解二氧化硫和氧气的反应细节的意义。

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.