Ligand-Metal Electron Transfer Processes in Complexes of Late Transition Metals with Redoxactive Guanidine Ligands: Fundamental Understanding and Applications in Redox Catalysis

具有氧化还原活性配体的配位化合物目前被广泛研究，这是因为配体的氧化还原活性具有额外的可能性。在催化应用中，氧化还原活性配体可以作为电子储存库来增强底物的活性。此外，氧化还原活性配体通常以自由基配体的形式存在，而配体上自旋密度的增加导致了一种特殊的以配体为中心的反应活性。最后，直接与氧化还原活性配体结合的金属的性质(例如Lewis酸度)会随着氧化还原活性配体的氧化还原状态而改变。我的研究小组研究具有氧化还原活性的胍类配体的配位化合物。这些配体可以分为两类，一类是由两个或多个直接连接到芳香族核上的胍基组成的瓜尼基-官能化芳香族化合物，另一类是由两个通过N-N键直接相连的胍基(或相关基团)组成的尿素氮杂环及其相关化合物。这两个复合班都与计划中的研究相关。该项目由TP1和TP2两个子项目组成。各种不同的刺激剂对分子内电子转移过程的直接刺激是TP1的主要主题。与第一个供资时期不同的是，第一个供资时期集中在最好是小的双和四氢呋喃配体上，氧化还原活性寡核苷酸，由两个或更多电子耦合的氧化还原活性单元构成，被纳入研究范围。TP1中的基础研究是TP2中关于键活化的一些工作的基础，以及具有氧化还原活性的胍类配体的配位化合物的催化应用。此外，我们还研究了在TP2中与自由氧化还原活性的胍类化合物的质子耦合电子转移反应。

Coordination compounds with redox-active ligands are currently intensively studied, due to the additional possibilities that arise from ligand redox-activity. A redox-active ligand could act as electron reservoir to enhance substrate activation in catalytic applications. Moreover, redox-active ligands often are present as radical ligands, and the increased spin density on the ligand leads to a special, ligand-centered reactivity. Finally, the properties (e.g. Lewis acidity) of a metal directly bound to a redox-active ligand change with the redox state of the redox-active ligand. My research group studies coordination compounds with redox-active guanidine ligands. These ligands could be devided into two classes, the Guanidino-Functionalized Aromatics (GFAs), consisting of two or more guanidino groups directly attached to an aromatic core, and the urea azines and related compounds, consisting of two guanidinyl groups (or related groups) that are directly connected to each other via an N-N bond. Both compound classes are of relevance for the planned studies. The project is composed of two sub-projects, TP1 and TP2. The directed stimulation of intramolecular electron-transfer processes by a variety of different stimulants is the main topic in TP1. In difference to the first funding period that concentrated on preferably small bis- and tetrakisguanidine ligands, redox-active oligoguanidines, built of two or more electronically coupled redox-active units, are included into the studies. The fundamental studies in TP1 are the basis for some of the work in TP2 on bond activations and catalytic applications with coordination compounds with redox-active guanidine ligands. Moreover, proton-coupled electron transfer reactions with free redox-active guanidines are studied within TP2.