GEOMETRIC AND ELECTRONIC STRUCTURAL STUDIES OF TRANSITION METAL DITHIOLENES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 三(二硫杂环戊烯)过渡金属络合物由于其独特的物理性质和电子结构，在无机化学领域引起了人们极大的兴趣。此外，三(二硫杂环戊烯)络合物是第一个具有三棱柱几何构型的离散分子，这一特征在几种钼和钨酶的氧化活性位上观察到，这些酶催化了各种基本的生化反应。在材料科学中，某些二硫杂环化合物由于其在近红外区的巨大吸收带而成为非线性光学器件和激光应用的候选材料。它们的可逆氧化还原化学已被用于生产半导体和超导材料和传感器。理解酶反应机理或设计新的功能材料应该建立在对这类化合物的电子结构的透彻理解的基础上。二硫杂环戊烯配体可以以自由基和双自由基的形式存在，并被描述为非无害的，这使得中心金属的氧化和自旋态变得模糊，很难通过实验确定。氧化的二硒烯烯类配体的存在仍然未知。因此，金属K边和L边以及硫和硒K边的X射线吸收光谱非常适合于为这些系统的功能提供基本的电子结构洞察。此外，金属和配体EXAFS将帮助定义固体和溶液状态下的度量参数。硫和硒的EXAFS可以很好地测量从三棱柱到八面体的几何变化，因为通过测量配体间的距离，络合物被顺序地还原。这些实验将结合准相对论密度泛函以及多重态计算，以便更深入地了解实验数据。我们的研究将集中在一系列系统地不同氧化状态的络合物，二硫烯烯/二硒烯烯取代基和

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. Tris(dithiolene) transition metal complexes have piqued considerable interest in inorganic chemistry due to their fascinating physical properties and electronic structures. Moreover, tris(dithiolene) complexes were the first discrete molecules to possess trigonal prismatic geometry, a feature observed in the oxidized active sites of several molybdenum and tungsten enzymes that catalyze a wide variety of fundamental biochemical reactions. In material sciences, certain dithiolene complexes are candidate materials for nonlinear optical devices and laser applications due to their enormous absorption bands in the near-infrared region. Their reversible redox chemistry has been utilized in the production of semi- and superconducting materials and sensors. The understanding of enzymatic reaction mechanisms or the design of new functional materials should be based on a thorough understanding of the electronic structures of such compounds. Dithiolene ligands can exist as radicals and diradicals and are described as ?non-innocent?, which makes the oxidation and spin states of the central metal ambiguous and difficult to determine experimentally. The existence of oxidized diselenolene ligands is still unknown. Thus, X-ray absorption spectroscopy at the metal K-, and L-edges as well as the sulfur and selenium K-edges is ideally suited to provide fundamental electronic structure insights into the function of these systems. Additionally, metal and ligand EXAFS will assist in defining metric parameters in the solid and solution state. Sulfur and selenium EXAFS are perfectly poised to gauge the geometric change from trigonal prismatic to octahedral as the complex is sequentially reduced by measuring interligand distances. The experiments will be combined with quasi-relativistic density functional as well as multiplet calculations in order to obtain more insight into the experimental data. Our studies will focus on a series of complexes which systematically differ in their oxidation states, dithiolene/diselenolene substituent and