【摘要】 利用飞秒及纳秒瞬态吸收光谱技术,研究了两种磷光型铱阳离子配合物[Ir（dph-oxd）₂（bpy）]PF₆（1）和[Ir（dphoxd）₂（pzpy）]PF₆（2）的溶剂相关激发态动力学.在两种配合物的瞬态吸收光谱实验中,配合物被光激发到¹MLCT态后,指征了一个受溶剂极性调控的快速演化过程（0.7～3 ps）,对应于溶剂稳定的³MLCT态的生成.随后通过振动冷却和结构稳定的慢过程,到达辐射磷光的最低三重态.由于辅助配体对电子态的调控作用,配合物1的溶剂化稳定速率较配合物2更快.本工作为理解配体调控功能型铱配合物的激发态动力学及三重激发态的溶剂化效应提供了新的视点.更多还原

【Abstract】 To elucidate the nature of low-lying triplet states and the effect of ligand modifications on the excited-state properties of functional cationic iridium complexes, the solventdependent excited-state dynamics of two phosphorescent cationic iridium（III） complexes,namely [Ir（dph-oxd）₂（bpy）]PF₆（1） and [Ir（dph-oxd）2（pzpy）]PF6（2）,were investigated by femtosecond and nanosecond transient absorption spectroscopy. Upon photoexcitation to the metal-to-ligand charge-transfer（MLCT） states, the excited-state dynamics shows a rapid process（τ=0.7-3 ps） for the formation of solvent stabilized ³ MLCT states, which significantly depends on the solvent polarity for both 1 and 2. Sequentially, a relatively slow process assigned to the vibrational cooling/geometrical relaxation and a long-lived phosphorescent emissive state is identified. Due to the different excited-state electronic structures regulated by ancillary ligands, the solvation-induced stabilization of the 3 MLCT state in 1 is faster than that in 2. The present results provide a better sight of excited-state relaxation dynamics of ligand-related iridium（III） complexes and solvation effects on triplet manifolds.更多还原