【摘要】 为了探究取代基对三联吡啶Pt(Ⅱ)配合物发光性质的影响,采用MP2和CIS方法分别对配合物[Pt(trpy)C≡CC6H4R]+[trpy=2,2′,6′,2″-Terpyridine;R=NO2(1),Cl(2),H(3),CH3(4)]的基态和激发态的几何构型进行了优化,通过TDDFT/B3LYP方法得到了这些化合物在二氯甲烷溶液中的磷光发射光谱以及它们的跃迁性质.研究结果表明,由于NO2的强吸引作用以及在C≡CC6H4NO2部分可能存在的电子共振结构,化合物1的最低发射可以指认为Pt—C≡C→trpy(3MLCT/3LLCT)的跃迁,并且还有很大的一部分来自于π→π*(C6H4NO2)跃迁的贡献,而化合物3和化合物4由于含有给电子基团,因此其最低发射仅仅是来自于3MLCT/3LLCT的跃迁.但是并不是所有的取代基为吸电子基团时都能有类似的π→π*跃迁性质.对于化合物2,Cl是仅次于NO2的吸电子取代基,但是由于缺少电子共振的贡献,它的跃迁性质却与化合物3和4相同.另外,激发态几何相对于基态几何没有发生太大的变化,这与实验上所观察到的较小斯托克斯频移现象一致.更多还原

【Abstract】 To explore the substituents how to affect the excited state for the the terpyridyl Pt(Ⅱ) complexes, we calculated a series of complexes [Pt(trpy)C≡CC6H4R]+[trpy=2,2′,6′,2″-Terpyridine; R=NO2(1), Cl(2), H(3) and CH3(4)]. MP2 and CIS methods were used to optimize the ground and excited states for the four complexes, and TDDFT method at B3LYP level was employed to obtain their phosphorescent emission spectra. The results reveal that the lowest-energy phosphorescence of compound 1 can be assigned as the Pt—C≡C→trpy charge transfer(3MLCT/3LLCT) transitions and perturbed by the π→π* transition localized on the C6H4NO2 moiety, due to the stronger electron-withdrawing ability of NO2 and the possible resonance structures in C≡CC6H4NO2. But the other three complexes were only attributed to 3MLCT/3LLCT characters. In addition, the excited-state structures are similar to those of the ground-state ones, which is in agreement with the small Stokes-shift in the experiments.更多还原