Photoinduced dynamics in bipyridylruthenium(II)-complexes: Investigation of activation and dissociation mechanisms by a combined approach of chemical synthesis and ultrafast spectroscopy in both gas phase and solution.

Ru(II)-配合物丰富的光物理和光化学性质在技术和医学上具有巨大的应用潜力。然而，络合物的化学组成与其光活化的具体基本步骤之间的重要关系尚未完全了解。这包括配体及其取代基对能量学和相关电子态耦合的影响，进而决定了功能重要的物理（如发光）和化学（如解离或配体交换）过程的量子产率。我们的提议提供了一种化学合成、飞秒时间分辨光谱和量子化学计算相结合的方法，旨在填补现有知识水平的空白，并导致更深层次的理解。因此，该建议的概念力量是由以下方面的协调努力提供的：配体、取代基及溶剂化变化的联吡啶钌配合物的化学合成。因此，可以调整特定的物理化学参数。这包括参与电子态的能量学，（光学）天线特性，用于跟踪特定过程的光谱“标记”的实现以及溶解度。2. 气相(i)和固相（ii）的飞秒时间分辨光谱。这允许首先(i)光诱导离解的灵敏检测，获得本征Ru（II）复合物的性质以及与量子化学（真空）计算结果更好的可比性，其次（II）电子（UV/Vis/NIR）和结构（中红外）动力学的研究以及在溶液阶段（即更现实）条件下的过程和中间状态的识别。3. 伴随量子化学计算，以便更好地评估配体和取代基变化时电子态能的趋势，并支持对实验结果的解释。此外，计算（在可行的情况下）与瞬态IR-和irmpd -光谱相连接，用于中间状态和物种的结构解析。

The rich photophysics and photochemistry of Ru(II)-complexes offers a huge potential for applications in technology and medicin. However, important relationships between the chemical constitution of the complexes and specific elementary steps of their photoactivation are not fully understood. This includes the impact of the ligands and their substituents on the energetics and the coupling of the relevant electronic states that, in turn, determine the quantum yield of functionally important physical (e. g. luminescence) and chemical (e.g. dissociation or ligand exchange) processes. Our proposal provides a combined approach of chemical synthesis, femtosecond time resolved spectroscopy and quantum chemical calculations, aiming at filling existing gaps in the current level of knowledge and leading to a deeper understanding. Thus the conceptional strength of the proposal is given by the coordinated efforts of: 1. Chemical synthesis of bipyridyl-ruthenium(II)-complexes with systematic variation of ligands, substituents and solvation. Thereby specific physicochemical parameters can be tuned. This includes the energetics of the participating electronic states, the (optical) antenna properties, implementation of spectroscopic "markers" for tracking specific processes as well as solubility. 2. Femtosecond time-resolved spectroscopy in both gas phase (i) and in solution phase (ii). This allows first (i) sensitive detection of photoinduced dissociation, access to intrinsic Ru(II)-complex properties and better comparability with results of quantum chemical (vacuum-) calculations, and second (ii) the investigation of electronic (UV/Vis/NIR) and structural (mid-IR) dynamics as well as the identification of processes and intermediate states under solution-phase (i. e. more realistic) conditions. 3. Accompanying quantum chemical calculations in order to better assess trends in electronic state energies upon variation of ligands and substituents and to support the interpretation of the experimental results. Furthermore, the calculations are used (where practicable) in connection with transient IR- and IRMPD-spectra for structural elucidation of intermediate states and species.