XAS STUDIES OF A METHANE HYDROXYLATING BINUCLEAR MODEL COMPLEX

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。合成并表征了一种新的双核铁模型配合物，它能高效地将甲烷转化为甲醇。其催化中间体的相对不稳定性和短寿命迄今为止妨碍了获得该中间体的结构数据。本文建议利用x射线吸收光谱（边缘和EXAFS）来解决电子和几何结构。中间体被认为含有一个混合价位点，特别是被认为由一个六坐标亚铁中心桥接到一个六坐标铁氧基部分组成。通过谨慎使用从催化前驱体和衰变产物数据中获得的信息，以及从额外的特定模型配合物中获得的信息，该混合物对中间体的预边缘、边缘和EXAFS数据的相对贡献将被分离，如提案中所述。该配合物的表征具有几个重要的意义：在甲烷到甲醇的工业转化中，作为无机模型配合物，以及作为甲烷单加氧酶的甲醇转化活性位点的模型。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A new binuclear iron model complex has been synthesized and characterized, which converts methane into methanol with high efficiency. The relative instability and short lifetime of its catalytic intermediate has thus far precluded obtaining structural data on this intermediate. It is proposed here to utilize x-ray absorption spectroscopy (edge and EXAFS) to address the electronic and geometric structure. The intermediate is thought to contain a mixed-valent site, specifically considered to be comprised of a six-coordinate ferrous center bridged to a six-coordinate ferryl-oxo moiety. Through prudent use of information obtained from data of the catalytic precursor and decay product, as well as from additional specific model complexes, the relative contributions of this mixture to the pre-edge, edge and EXAFS data of the intermediate will be separated, as described in the proposal. The characterization of this complex has several important implications: in the industrial conversion of methane to methanol, as an inorganic model complex, and as a model of the methanol-converting active site of methane monooxygenase.