F原子对过渡金属铱配合物结构和光谱性质的影响

The Effect of F Substituent on the Electron Structures and Spectroscopic Properties of Transition Metal Iridium Complexes

采用密度泛函方法研究了一系列(C^N)2Ir(idpt)[C^N=2-苯基吡啶(1),2-(5-氟苯基)吡啶(2),2-(4,5,6-三氟苯基)吡啶(3),idpt=亚氨基二磷酸盐]配合物的几何结构和光谱特征.使用B3LYP/LanL2DZ泛函得到配合物1-3的基态几何结构,同时使用相关的UB3LYP/LanL2DZ泛函优化了其激发态结构.计算得到的Ir-N(1)、Ir-C(1)和Ir-O(1)基态键长和相应实验值符合得较好.在TD-DFT和CPCM计算水平下,得到1-3的最低能吸收和发射分别出现在447(1)、452(2)、424(3)nm和541(1)、499(2)、466(3)nm.这些激发的起始轨道HOMOs,主要由金属和两个双齿配体占据,而终止轨道LUMOs均为占据在两个双齿配体上的*型轨道,该跃迁被指认为金属到配体和配体到配体的电荷转移(MLCT/LLCT)跃迁.计算结果显示出,该类配合物的发光颜色受苯基吡啶配体自身和F取代基的双重影响.

The structures and spectroscopic properties of a series of(C^N)2Ir(idpt)[C^N=2-phenylpyridine(1),2-(5-fluorophenyl)pyridine(2),2-(4,5,6-trifluorophenyl)pyridine(3),idpt=imidodiphosphinate]complexes were investigated by the density functional methods.We first optimized geometrical structure in ground state of complexes 1-3,at the B3LYP/LanL2DZ levels,and the excited state structures by selected UB3LYP/LanL2DZ functional.The calculated bond lengths of Ir-N(1),Ir-C(1),and Ir-O(1)in the ground state agree well with the corresponding experimental results.At the TD-DFT and CPCM levels,1-3 give rise to lower energy absorptions at 447(1),452(2),424(3)nm and corresponding phosphorescent emissions at 541(1),499(2),466(3)nm,respectively.The HOMOs of 1-3 are mainly localized on the metal and bidentate ligands,while the LUMOs are the*type orbital of bidentate ligands.Therefore,the transition of 1-3 were assigned to the metal-to-ligand and ligand-to-ligand charge transfer(MLCT/LLCT)transition.It is shown that the emitting color are significantly dominated by the phenylpyridine ligand itself and F-substituent group.