Boden Pit, Di Martino-Fumo Patrick, Busch Jasmin M, Rehak Florian R, Steiger Sophie, Fuhr Oliver, Nieger Martin, Volz Daniel, Klopper Willem, Bräse Stefan, Gerhards Markus
Chemistry Department and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663, Kaiserslautern, Germany.
Institute of Organic Chemistry (IOC), Karlsruhe Institute of, Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.
Chemistry. 2021 Mar 22;27(17):5439-5452. doi: 10.1002/chem.202004539. Epub 2021 Jan 15.
To develop new and flexible Cu containing luminescent substances, we extend our previous investigations on two metal-centered species to four metal-centered complexes. These complexes could be a basis for designing new organic light-emitting diode (OLED) relevant species. Both the synthesis and in-depth spectroscopic analysis, combined with high-level theoretical calculations are presented on a series of tetranuclear Cu complexes with a halide containing Cu X core (X=iodide, bromide or chloride) and two 2-(diphenylphosphino)pyridine bridging ligands with a methyl group in para (4-Me) or ortho (6-Me) position of the pyridine ring. The structure of the electronic ground state is characterized by X-ray diffraction, NMR, and IR spectroscopy with the support of theoretical calculations. In contrast to the para system, the complexes with ortho-substituted bridging ligands show a remarkable and reversible temperature-dependent dual phosphorescence. Here, we combine for the first time the luminescence thermochromism with time-resolved FTIR spectroscopy. Thus, we receive experimental data on the structures of the two triplet states involved in the luminescence thermochromism. The transient IR spectra of the underlying triplet metal/halide-to-ligand charge transfer ( M/XLCT) and cluster-centered ( CC) states were obtained and interpreted by comparison with calculated vibrational spectra. The systematic and significant dependence of the bridging halides was analyzed.
为了开发新型且灵活的含铜发光物质，我们将之前对两种金属中心物种的研究扩展到了四种金属中心配合物。这些配合物可能是设计新型有机发光二极管（OLED）相关物种的基础。本文介绍了一系列四核铜配合物的合成、深入的光谱分析以及高水平理论计算，这些配合物含有卤化铜（CuX）核心（X = 碘化物、溴化物或氯化物）以及两个在吡啶环对位（4-Me）或邻位（6-Me）带有甲基的2-(二苯基膦基)吡啶桥连配体。在理论计算的支持下，通过X射线衍射、核磁共振和红外光谱对电子基态结构进行了表征。与对位体系不同，具有邻位取代桥连配体的配合物表现出显著且可逆的温度依赖性双重磷光。在此，我们首次将发光热致变色与时间分辨傅里叶变换红外光谱相结合。因此，我们获得了关于发光热致变色中涉及的两个三重态结构的实验数据。通过与计算振动光谱进行比较，获得并解释了潜在的三重态金属/卤化物到配体电荷转移（M/XLCT）和簇中心（CC）态的瞬态红外光谱。分析了桥连卤化物的系统且显著的依赖性。
