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

这项建议的目的是通过合成和高级光谱学相结合的方法来实现对零型铜化合物的更好的理解。旨在开发新型零型铜系仿生模型络合物，并应用拉曼光谱和X射线光谱分析方法研究其激发态。这种由X射线吸收光谱(XAS)、X射线发射光谱(XES)、高能量分辨荧光检测XAS(HERFD-XAS)、拉曼光谱和泵浦探测测量与电化学实验相结合的多维光谱方法是独一无二的。它将允许研究铜(I)/铜(II)氧化还原对各个物种的电子结构和几何结构，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，零型蛋白质模型配合物含有N，N‘和N，O给体配体将被制备，即双(吡唑基)苯酚甲烷铜配合物和双(吡唑基)酚甲烷铜配合物。由于以下原因，合成和光谱之间的互连是强制性的：配体的设计是光谱辅助的，即配体取代的选择是基于吸收和发射性质的。另一方面，所制备的配合物的光谱表征将证明它们作为结构模型的有效性。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效性。最终，最好的模型将受到详细的光谱研究，包括它们的电子结构和几何结构，这两种结构相互之间的矛盾影响，以及它们在光激发和电化学实验中的动态演变。虽然常规的XAS和泵浦-探测XAS已经为研究小组的目的而开发和建立，但K边XES和HERFD-XAS应用于Type Zero系统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测量X射线和拉曼的光谱电化学池来完成。结合共振拉曼和L边缘XAS，该项目将允许对零型铜蛋白质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.