Mono- and Bimetallic Cyclometalated Transition Metal NHC Complexes

在过去的几年里，我们的部分研究项目涉及不同过渡金属(Ag、Au、Ir、铂、Ru)的环金属NHC-配合物的合成。我们的重点是金属有机化合物作为有机电致发光器件的磷光发射体和催化活性络合物。在研究过程中，我们注意到了一些化合物，根据它们的吸收光谱和激发态的衰减时间，它们应该具有特定的光催化潜力。一个例子可能是异感的Ru络合物[Ru(Bpy)2(C^C*)](PF6)，其中在适当的测试反应中与类似的[Ru(Bpy)3]2+络合物的比较应该允许洞察活性物种。此外，我们还可以合成含酰胺/吡唑配体的双金属铂(II)配合物。根据量子化学计算的第一次评估，它们的金属-金属-距离强烈依赖于酰胺/吡唑基上的基团和由此产生的配体的几何形状，这应该会对激发态的形成产生强烈的影响。这使我们能够将反应性与激发态的形成联系起来。因此，这个项目的一个重要目标是合成新的单金属和双金属环金属化的C^C*-铂(II)和-Ru配合物，以及对已经存在的具有显著长的衰减时间和合适的吸收光谱的配合物进行深入的研究。研究这些化合物的模型反应将使我们能够得出关于活性物种的结论。实验工作将由CV测量和带有色散校正的高水平密度泛函计算来补充，以评估前线轨道和激发态。对于新化合物的非常先进的光谱研究，我们希望SPP内部的合作将使该仪器得以使用。

In the last years part of our research program involved the synthesis of cyclometalated NHC-complexes of different transition metals (Ag, Au, Ir, Pt, Ru). We focused on metalorganic compounds for use as phosphorescent emitters for OLEDs and catalytically active complexes. In the course of this research we noticed several compounds, which should possess a specific potential for photo-catalysis based on their absorption spectra and decay times of the excited state. One example might be a heteroleptic ruthenium complex [Ru(bpy)2(C^C*)](PF6) where the comparison with the analogous [Ru(bpy)3]2+ complex in appropriate test reactions should allow for insight into the active species. Furthermore we could synthesize bimetallic platinum(II) complexes with amidinate/pyrazolate ligands. Their metal-metal-distance is, according to a first assessment by quantum chemical calculations, strongly dependent from the groups at the amidinate/pyrazolate and the resulting geometry of the ligands, which should exert a strong influence on the formation of the excited state. This allows us to correlate the reactivity with the formation of the excited states. One important goal of this project therefore is the synthesis on new mono- and bimetallic cyclometalated C^C*-platinum(II) and –ruthenium complexes as well as the thorough study of already existing complexes with strikingly long decay times and suitable absorption spectra.Studying these compounds in model reactions will allow us to draw conclusions on the active species. The experimental work will be complemented by CV measurements and high-level DFT calculations with dispersion correction to evaluate the frontier orbitals and the excited states. For the very advanced spectroscopic investigations of the new compounds we hope that collaborations within the SPP will give access to that instrumentation.