Phosphorescent Cationic Iridium（Ⅲ） Complexes with 1,3,4-Oxadiazole Cyclometalating Ligands： Solvent-Dependent Excited-State Dynamics  

1，3,4-噁二唑环金属配体的磷光型铱阳离子配合物：溶剂相关的激发态动力学研究

作　　者：匡卓然 王娴[1,2] 王振[3] 何桂营 郭前进[1] 何磊[3] 夏安东[1,2] 

机构地区：[1]中国科学院化学研究所,北京分子科学国家实验室,光化学重点实验室,北京100190 [2]中国科学院大学,北京100049 [3]中南大学化学化工学院,长沙410083

出　　处：《Chinese Journal of Chemical Physics》2017年第3期259-267,I0001,共10页化学物理学报（英文）

摘　　要：To elucidate the nature of low-lying triplet states and the effect of ligand modifica- tions on the excited-state properties of functional cationic iridium complexes, the solvent- dependent 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 3MLCT 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 phospho- rescent emissive state is identified. Due to the different excited-state electronic structures regulated by ancillary ligands, the solvation-induced stabilization of the 3MLCT 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.

关 键 词：Iridium complex PHOSPHORESCENCE Metal-to-ligand charge transfer Transientabsorption SOLVATION 

分 类 号：O[理学]