Development of cComputing system for predicting photophysical properties of transition metal compounds

强发光过渡金属化合物作为有机电致发光器件等新型器件近年来受到人们的关注。这些化合物的强磷光来源于过渡金属离子p或d轨道的强自旋轨道耦合。在这项工作中，一个程序，它允许计算相对较大的分子含有重过渡金属的辐射率或零场分裂的物理性质，已开发的含时密度泛函理论的基础上。计算得到的Ir（ppy）3和[Ru（bpy）3]2+三重态子能级的零场分裂和振子强度与观测值符合得很好。虽然[Ru（bpy）_3]^<2+>的激发态是否局域化一直存在争议，但其电子构型仍存在争议。本文采用绝热势面的谐振子近似方法计算了[Ru（bpy）_3]^<2+>的磷光光谱。光谱模拟表明，[Ru（bpy）_3]^<2+>的磷光态在单晶、溶液和玻璃基质中都是局域的^[3 MLCT]。然而，由于局域MLCT态沿着高频C-C伸缩振动模之间的强电子振动耦合，使得局域MLCT等简单绝热图像被部分破坏，它们的振动波函数出现了混合，在高发光d 6金属化合物的光稳定性或光反应性中，高激发态dd起着非常重要的作用。本文采用计算化学方法研究了[Ru（bpy）_3]^<2+>中MLCT的失活过程。确定了dd态的结构和涉及失活途径的势能曲线。

Intensely emissive transition-metal compounds have been paid attention as novel devises such as organic light emitting diodes recently. Strong phosphorescence of these compounds originates from strong spin-orbit coupling of p or d orbitals of transition metal ions. In this work, a program, which allows calculating photophysical properties such as radiative rate or zero-field splitting of relatively large molecules containing heavy transition-metals, has been developed based on time-dependent density functional theory. The calculated zero-field splitting and oscillator strength of triplet sublevels of Ir(ppy)3 and [Ru(bpy)3]2+ are in good agreement of the observed ones. Furthermore, it is demonstrated that the mechanism of phosphorescence of these metal compounds are well rationalized in terms of M-bpy sub-unit model with C2v point group.Although it has been argued for a long time whether the excited state in [Ru(bpy)_3]^<2+> is localized, the electronic configuration in the single crystals is still under debate. In this work, phosphorescence spectra of [Ru(bpy)_3]^<2+> were calculated using a harmonic oscillator approximation of adiabatic potential surfaces obtained by DFT. The spectrum simulation revealed that the phosphorescent state of [Ru(bpy)_3]^<2+> was localized ^3MLCT in a single crystal as well as in a solution and a glass matrix. However, due to strong vibronic coupling between localized MLCT states along high-frequency C-C stretching vibrational modes, simple adiabatic picture such as localized MLCT is partially broken and their vibrational wavefunctions are somehow mixed.In the photostability or photoreactivity of the highly luminescent d6 metal compounds, higher-lying triplet dd excited states are known to play very important rules. In this work, the deactivation of MLCT in [Ru(bpy)_3]^<2+> was investigated by computational chemistry. The structures of the dd states and the potential energy curves involving the deactivation pathways were determined.