[Ir(ppy)2(X- ppz)]+配合物结构和光谱性质的量子理论研究

从理论上研究了一系列Ir(ppy)₂(ppz)]⁺ (1)，Ir(ppy)₂(ph-ppz)]⁺ (2)，Ir(ppy)₂(ph-ppz)]⁺(3)（3与2的区别在于苯环的连接位置不同）ppy=苯基吡啶，ppz =2-吡啶基吡唑，ph=苯基]配合物的几何构型和光谱特征。采用B3LYP泛函和单激发组态相互作用(CIS)方法计算了基态(S₀)和最低能三重激发态(T₁)结构，用含时密度泛函方法结合PCM溶剂模型计算三个分子在二氯甲烷溶剂中的吸收和发射光谱。研究结果表明，Ir-N3和Ir-N4优化结构数据与相应的实验值近似相同。配合物1-3的最低能吸收在447.91 nm、456.52 nm和516.90 nm，磷光发射在512.02 nm、501.14 nm和562.29 nm。它们的最高占据轨道(HOMO)主要由金属Ir和配体ppy占据，而最低空轨道(LUMO)均为占据在ppz配体上的π*型轨道，因此该跃迁属于金属到ppz配体和ppy配体到ppz配体的(MLCT/LLCT)电荷转移跃迁。并且，此类配合物的吸收和发射受ppy和ppz配体影响较大。

Theoretical Studies on the Electronic Structures and Spectroscopic Properties for a Series of [ Ir( ppy) 2( X-ppz) ]+Complexes

The geometries and spectroscopic properties of Ir(ppy)₂(ppz)]⁺(1), Ir(ppy)₂(ppz)]⁺(2), Ir(ppy)₂(ppz)]⁺ (3) (3 and 2 are different in the connection position of benzene ring) ppy=phenylpyridine, ppz=(2-pyridyl)pyrazole, ph=phenyl] complexes were studied theoretically. B3LYP functional and single excited configuration interaction (CIS) methods were used to optimize the S₀ and T₁ structures. The absorption and emission spectra of the complexes in CH2Cl2 solution were calculated by time dependent density functional theory (TD-DFT) and polarized continuum model (PCM). The results show that Ir-N3 and Ir-N4 obtained by the ground state optimization are in good agreement with the corresponding experimental values. The lowest energy absorption of complexes 1-3 is 447.91 nm, 456.52 nm and 516.90 nm, and the phosphorescence emission is 512.02 nm, 501.14 nm and 562.29 nm, respectively. The highest occupied molecule orbit (HOMO) of complexes 1-3 is mainly occupied by Ir and ppy, and the lowest unoccupied orbit (LUMO) is occupied by ppz ligands π* orbit. Therefore, this transition is referred to as the metal to ppz ligand and ppy ligand to ppz ligand charge transfer (MLCT/LLCT) transition. Moreover, the absorption and emission of these complexes are greatly influenced by ppy and ppz ligands.