Wang Zhiqiang, Zheng Caijun, Wang Weizhou, Xu Chen, Ji Baoming, Zhang Xiaohong
College of Chemistry and Chemical Engineering, Luoyang Normal University , Luoyang, Henan 471022, P. R. China.
Nano-organic Photoelectronic Laboratory and Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.
Inorg Chem. 2016 Mar 7;55(5):2157-64. doi: 10.1021/acs.inorgchem.5b02546. Epub 2016 Feb 23.
Two luminescent cationic heteroleptic four-coordinate Cu(I) complexes supported by N-heterocyclic carbene ligand and diphosphine ligand were successfully prepared and characterized. These complexes adopt typical distorted tetrahedral configuration and have high stability in solid state. Quantum chemical calculations show carbene units have contributions to both highest occupied molecular orbitals and lowest unoccupied molecular orbitals of these Cu(I)-NHC complexes, the lowest-lying singlet and triplet excitations (S0 → S1 and S0 → T1) of Cu(Pyim)(POP) are dominated by metal-to-ligand charge transfer (MLCT) transition, while the S0 → S1 and S0 → T1 excitations of Cu(Qbim)(POP) are mainly MLCT and ligand-centered transitions, respectively. These Cu(I)-NHC complexes show efficient long-lifetime emissions (λem = 520 nm, τ = 79.8 μs, Φ = 0.56 for Cu(Pyim)(POP), λem = 570 nm, τ = 31.97 μs (78.99%) and 252.2 μs (21.01%), Φ = 0.35 for Cu(Qbim)(POP)) in solid state at room temperature, which are confirmed as delayed fluorescence by investigating the emissions at 77 K.
成功制备并表征了两种由N-杂环卡宾配体和二膦配体支撑的发光阳离子异质四配位Cu(I)配合物。这些配合物采用典型的扭曲四面体构型，在固态下具有高稳定性。量子化学计算表明，卡宾单元对这些Cu(I)-NHC配合物的最高占据分子轨道和最低未占据分子轨道都有贡献，Cu(Pyim)(POP)的最低单重态和三重态激发（S0 → S1和S0 → T1）以金属到配体的电荷转移（MLCT）跃迁为主，而Cu(Qbim)(POP)的S0 → S1和S0 → T1激发分别主要是MLCT和配体中心跃迁。这些Cu(I)-NHC配合物在室温固态下表现出高效的长寿命发射（对于Cu(Pyim)(POP)，λem = 520 nm，τ = 79.8 μs，Φ = 0.56；对于Cu(Qbim)(POP)，λem = 570 nm，τ = 31.97 μs（78.99%）和252.2 μs（21.01%），Φ = 0.35），通过研究77 K下的发射被确认为延迟荧光。
