环金属铱配合物的分子设计

苯并噻吩铱配合物通常发红光，且具有较强的电致发光性能，因此被广泛的应用于光电显示领域。以2-(苯并噻吩-2-基)喹啉为基础配体，从理论上研究了三个同分异构体铱(btq)2Ir(pic)]btq=2-(苯并噻吩-2-基)喹啉(1)；3-(苯并噻吩-2-基)异喹啉(2)；1-(苯并噻吩-2-基)异喹啉(3)；pic=吡啶甲酸酯]配合物的电子结构和光谱特征。采用B3LYP和CIS方法优化了它们的S0和T1态几何结构，利用TD-DFT方法，结合CPCM溶剂模型模拟了它们在CH2Cl2溶剂中的吸收和发射光谱。研究结果表明：计算得到的分子结构参数与相对应的实验值吻合的较好。三个配合物的最低能吸收和发射分别在488 (1)、455 (2)、485 (3)和679 (1)、642 (2)、683 nm (3)。其最高占据分子轨道由金属的d轨道和btq配体的π成键轨道占据, 而最低空轨道为占据在btq配体上的π反键轨道。因此，最低能吸收和发射均被指认为金属到btq配体(MLCT)和btq配体内部(ILCT)的电荷转移跃迁。苯环连接位置的改变并未对配合物主体结构产生重大影响，但空间位阻和共轭效应的双重作用足以改变其发光颜色。

Molecular Design Research on a Series of Cyclometalated Iridium Complexes

Iridium benzothiophen complexes with red light emission has strong electroluminescence performance, which have been widely applied in photoelectric display field. Take 2-(benzothiophen-2-yl)- quinoline as basic ligand, the electronic structures and spectroscopic properties of a series of isomer iridium (btq)2Ir(pic) btq=2-(benzothiophen-2-yl)quinolin(1), 3-(benzothiophen-2-yl)isoquinoline(2), 1-(benzothio- phen-2-yl)isoquin/oline(3), pic=picolinate ancillary ligands] complexes have been investigated theoretically. Their structures of S0 and T1 were optimized by the B3LYP and CIS methods, the TD-DFT method with the CPCM model were used to obtain their absorption and phosphorescent emission spectra in CH2Cl2 media. The results revealed that the optimized structural parameters agreed well with the corresponding experimental results. The lowest-lying absorptions and emissions are at 488 (1), 455 (2), 485 (3) and 679 (1), 642 (2), 683 nm(3), respectively. The highest occupied molecular orbitals were localized mainly on the d orbital of the metal and the π orbital of the btq ligand for 1-3, while the lowest unoccupied molecular orbitals were mainly composed of π* orbital of the btq ligand. Therefore, the lowest-lying absorptions and emissions were assigned to the metal to btq ligand charge transfer (MLCT)/intra-ligand charge transfer (ILCT) transition. The change of benzene ring position has no significant effect on the main structure of these complexes, but both steric hindrance and conjugation have significantly effect on its luminous color.