State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China.
Dalton Trans. 2018 Jul 24;47(29):9779-9786. doi: 10.1039/c8dt01922c.
Cyclometalated Ir(iii) complexes [Ir(tpy)(bbibH2)Cl][PF6] (1·PF6) and [Ir(tpy)(bmbib)Cl][PF6] (2·PF6), and the control complex [Ir(tpy)(mbib)Cl][PF6] (3·PF6) were synthesized at 135 °C for 10 hours for the former two complexes, while at 190 °C for 24 hours for the latter complex, in which the cyclometalated ligands bbibH2-, bmbib- and mbib- incorporate one or two N-methylbenzoimidazole/benzimidazole units in order to explore the influence of the molecular structures of these complexes on their synthesis conditions and luminescence behaviors. The 1H NMR and crystal structure measurements indicate that both 1·PF6 and 2·PF6 contain intramolecular ππ stacking interactions between the non-coordinated N-methylbenzoimidazole/benzimidazole unit and the tpy ligand, but there are no such ππ interactions in 3·PF6. At room temperature, these complexes in CH3CN reveal an emission with a combination of 3MLCT and 3LC characteristics, occurring at 534 nm with a quantum yield Φ = 39.5% and a lifetime τ = 2.39 μs for 1·PF6, 536 nm with Φ = 66.4% and τ = 2.94 μs for 2·PF6, and 558 nm with Φ = 27.0% and τ = 1.75 μs for 3·PF6. Moreover, both 1·PF6 and 2·PF6 exhibit a TFA-induced luminescence decrease. Based on the comparison among 1·PF6, 2·PF6 and 3·PF6, we discuss the influence of intramolecular ππ interactions and Nimidazole-H/Nimidazole-CH3 units in 1·PF6 and 2·PF6 on their syntheses and luminescence.
环金属化 Ir(iii) 配合物 [Ir(tpy)(bbibH2)Cl][PF6]（1·PF6）和 [Ir(tpy)(bmbib)Cl][PF6]（2·PF6）以及对照配合物 [Ir(tpy)(mbib)Cl][PF6]（3·PF6）在 135°C 下分别反应 10 小时和 190°C 下反应 24 小时合成得到，其中环金属化配体 bbibH2-、bmbib-和 mbib-分别含有一个或两个 N-甲基苯并咪唑/苯并咪唑单元，以探索这些配合物的分子结构对其合成条件和发光行为的影响。1H NMR 和晶体结构测量表明，1·PF6 和 2·PF6 都含有非配位的 N-甲基苯并咪唑/苯并咪唑单元与 tpy 配体之间的分子内 ππ 堆积相互作用，但 3·PF6 中不存在这种 ππ 相互作用。在室温下，这些配合物在 CH3CN 中呈现出 3MLCT 和 3LC 特征的组合发射，在 534nm 处具有量子产率 Φ=39.5%和寿命 τ=2.39μs 的 1·PF6、在 536nm 处具有 Φ=66.4%和 τ=2.94μs 的 2·PF6、在 558nm 处具有 Φ=27.0%和 τ=1.75μs 的 3·PF6。此外，1·PF6 和 2·PF6 都表现出 TFA 诱导的发光减少。基于 1·PF6、2·PF6 和 3·PF6 之间的比较，我们讨论了分子内 ππ 相互作用和 Nimidazole-H/Nimidazole-CH3 单元对它们的合成和发光的影响。
