Charge transfer Raman, XES and (HR)XAS studies on Type Zero model complexes

该提案的目的是通过综合合成和先进的光谱方法来提高对铜零型化合物的理解。本论文的目标是开发新型的零型铜体系的仿生模型配合物，并应用拉曼和X射线光谱方法研究这些配合物的激发态。这种多维光谱方法可通过X射线吸收光谱（XAS）、X射线发射光谱（XES）、高能量分辨率的荧光XAS检测（HERFD-XAS），拉曼光谱和泵浦-探测测量与电化学实验相结合是实现这一目的的独特手段，它将允许研究Cu（I）/Cu（II）体系中各个物种的电子和几何结构氧化还原对以及这两个参数在化学、电化学和光诱导氧化还原过程中的动力学。在该项目的合成部分，将制备带有N，N ′以及N，O供体配体的零型蛋白的模型复合物，即胍双（螯合）铜络合物和双（吡唑基）苯酚甲烷铜酚盐络合物。由于以下原因，合成和光谱学之间的互连是强制性的：配体设计是光谱辅助的，即配体取代的选择是基于吸收和发射性质。另一方面，所制备的配合物的光谱表征将证明其有用的结构模型。最后，对它们的电子转移性质的研究将确定它们作为功能模型的有用性。最好的模型将最终进行详细的光谱研究，研究它们的电子和几何结构，这两种结构对彼此的矛盾影响，以及它们在光激发后和电化学实验期间的动态演变。虽然传统的XAS和泵浦-探测XAS已经为研究小组的目的开发和建立，但应用于零型系统的K边XES和HERFD-XAS的实验和理论基础是该项目的关键光谱发展之一。这包括开发用于XES和HERFD-XAS的X射线光谱电化学池，以及探索性的泵浦探测实验，这将通过开发用于同时进行X射线和拉曼测量的光谱电化学池来完成。结合共振拉曼和L边XAS，该项目将使人们对零型铜蛋白的工作原理有独特的新见解。作为最终目标，我们的目标是开发一种基于小分子零型类似物的光学触发快速电子转移系统，并了解与电子电荷转移相关的伴随结构扭曲及其对系统功能的影响。

The aim of this proposal is to achieve an improved understanding of copper Type Zero compounds by a combined synthetic and advanced spectroscopy approach. It is targeted at the development of new biomimetic model complexes for Type Zero copper systems and the application of Raman and X-ray spectroscopic methods on these complexes in order to study their excited states. Such a multi-dimensional spectroscopic approach by X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), high energy resolution fluorescence detected XAS (HERFD-XAS), Raman spectroscopy and pump-probe measurements in combination with electrochemical experiments is unique for that purpose.It will allow to study the electronic and geometric structure of the individual species of the Cu(I)/Cu(II) redox pair as well as the kinetics of these two parameters in course of chemical, electrochemical and photoinduced redox processes.In the synthetic part of the project, model complexes for Type Zero proteins bearing N,N´ as well as N,O donor ligands will be prepared, i.e. guanidine bis(chelate) copper complexes and bis(pyrazolyl)phenolmethane copper phenolate complexes.The interconnection between synthesis and spectroscopy is mandatory due to following reasons: The ligand design is spectroscopy aided, i.e. the choice of ligand substitution is based on absorption and emission properties. On the other hand, the spectroscopic characterization of the prepared complexes will prove their usefulness as structural models. Finally the investigation of their electron transfer properties will determine their usefulness as functional models.The best models will finally be subjected to detailed spectroscopic investigations of their electronic and geometric structure, the ambivalent influence of these two structures on each other, and their dynamic evolution after photoexcitation and during electrochemical experiments. While conventional XAS and pump-probe XAS were already developed and established for the purpose of the research group, the experimental and theoretical foundations for K-edge XES and HERFD-XAS applied to Type Zero systems are one of the key spectroscopic developments of this project. This includes the development of an X-ray spectro-electrochemical cell for XES and HERFD-XAS as well as exploratory pump-probe experiments, which will be completed by the development of a spectro-electrochemical cell for simultaneous X-ray and Raman measurements.In combination with resonance Raman and L-edge XAS, this project will allow unique new insights into the working principle of Type Zero copper proteins. As ultimate goal, we target the development of an optically triggered fast electron transfer system based on the small molecule Type Zero analogues and to understand the concomitant structural distortions associated with the electronic charge transfer and its impact on the function of the system.