Copper Sulfide Model Complexes for Small Molecule Activation

二氧化碳和一氧化二氮的大气浓度是地球上最重要的温室气体， 两者都部分地由含有多金属铜硫化物活性位点的金属蛋白调节。的性质 多金属协同在这些活性位点和保守的铜硫化物结构的作用，因为它 与酶的功能有关的研究知之甚少。本申请的目的是使用合成模型 研究了解自然界的特权铜硫化物簇基序在促进多金属 与CO2和N2 O的多电子/多质子调节相关的协同性。我们的核心假设 桥接硫原子既共价介导各个金属位点的氧化还原偶联， 参与小分子底物的共价活化。我们追求这一目标的理由是 它将为关键的多电子氧化还原转化提供信息并激发未来的催化剂设计， 依赖于CO2、N2 O和其他小分子底物。我们将努力实现全面 目的通过以下具体目标：1）开发四铜，二铜， 单硫原子桥的铜钼簇合物; 2）进行组合光谱- 不同原子簇氧化态的电子结构的计算研究; 3）研究 化学计量和催化反应与CO2，N2 O和相关的模型基板。拟议的研究是 重要的是，因为在访问这种模型复合体的综合困难已经排除了他们的仔细 研究到现在，所以我们的团队是在一个独特的位置，作出重要贡献，推动该领域的发展 垂直.这种方法是创新的，因为它给了我们一种独特的能力， 配位化学问题，通过合理设计构建结构忠实的模型体系。 实现该提案的目标将对化学界产生积极影响， 小分子的多电子/多质子转换不仅对生物系统至关重要， 包括替代能源转换和储存在内的许多前沿领域。

Atmospheric concentrations of CO2 and N2O, the #1 and #2 most consequential greenhouse gases on earth, both are regulated in part by metalloproteins containing multimetallic copper-sulfide active sites. The nature of multimetallic cooperativity in these active sites and the role of the conserved copper-sulfide structure as it relates to enzymatic function are poorly understood. The objective of this application is to use synthetic model studies to understand the role of nature's privileged copper-sulfide cluster motif in facilitating multimetallic cooperativity associated with multielectron/multiproton regulation of both CO2 and N2O. Our central hypothesis is that the bridging sulfur atoms both covalently mediate redox coupling of the individual metal sites, and also participate in covalent activation of the small molecule substrates. Our rationale for pursuing this objective is that it will inform and motivate future catalyst designs for crucial multielectron redox transformations that depend on CO2, N2O, and other small-molecule substrates. We will work towards achieving the overall objective by pursuing the following specific aims: 1) develop synthetic methods for tetracopper, dicopper, and copper-molybdenum clusters with single sulfur atom bridges; 2) conduct combined spectroscopic- computational studies of electronic structure across different cluster oxidation states; 3) investigate stoichiometric and catalytic reactions with CO2, N2O, and related model substrates. The proposed research is significant because the synthetic difficulty in accessing such model complexes has precluded their careful study until now, and so our team is in a unique position to make important contributions that advance the field vertically. This approach is innovative because it gives us a unique ability to address biologically relevant coordination chemistry questions with structurally faithful model systems constructed through rational design. Attaining the objective of the proposal will positively impact the chemical community, as multielectron/multiproton transformations of small molecules are crucial not only to biological systems but also to many frontier areas including alternative energy conversion and storage.