Mono- and Bimetallic Cyclometalated Transition Metal NHC Complexes

在过去的几年中，我们的研究计划的一部分涉及不同过渡金属（Ag，Au，Ir，Pt，Ru）的环化NHC-配合物的合成。我们专注于金属有机化合物用作OLED的磷光发射体和催化活性配合物。在这项研究的过程中，我们注意到几种化合物，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。一个例子可能是混配钌络合物[Ru（bpy）2（C^C*）]（PF 6），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质。此外，我们还可以合成脒基/吡唑基铂（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脒基/吡唑基上的基团和配体的几何形状，这对激发态的形成产生了强烈的影响。这使我们能够将反应性与激发态的形成联系起来。 因此，该项目的一个重要目标是合成新的单环和双环取代的C^C*-铂（II）和-钌配合物，以及对已经存在的具有惊人的长衰减时间和合适的吸收光谱的配合物进行深入研究。实验工作将通过CV测量和具有色散校正的高水平DFT计算来补充，以评估前沿轨道和激发态。对于新化合物的非常先进的光谱研究，我们希望SPP内部的合作将提供使用该仪器的机会。

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.