双核Au(Ⅰ)配合物[Y+]2[Au(i-mnt)]2(Y+=[n-Bu4N]+,K+,[Ph4As]+)发光机制的从头计算研究

用从头算方法研究Au(i-mnt)]22-(i-mnt=i-marononitriledithiolate)的电子吸收和磷光发射性质,利用MP2和CIS方法分别优化了Au(i-mnt)]22-基态和激发态几何结构.计算的基态Au(Ⅰ)—Au(Ⅰ)键长为0.2825nm,表明Au(Ⅰ)之间存在弱吸引作用.采用SCRF方法中IPCM模型模拟配合物在乙氰溶液中的行为,计算得到的最大吸收波长为315.5nm,指认X1Ag→A1Au来源于i-mnt配体内电荷转移跃迁.在436.2nm处得到具有B3Au→1Ag跃迁的磷光发射,指认为i-mnt配体内电荷转移和金属到配体电荷转移跃迁,与500nm乙氰溶液的发射相对应,为金属修饰的有机配体发光机制.

The Ab initio Study of Luminescent Mechanism for Dinuclear Complex,[Y+]2[Au(i-mnt)]2(Y+=[n-Bu4N]+, K+, [Ph4As]+)

The structures of Au(i-mnt)]22- (i-mnt=i-marononitriledithiolate) were optimized by the ab initio MP2 and CIS methods for the ground state and excited state respectively. The calculated ground-state Au(Ⅰ)-Au(Ⅰ) distance of 0.282 5 nm indicates a weak attraction between the two metallic Au(Ⅰ) atoms. The IPCM(Isodensity Polarized Continuum Model) approach in the SCRF (Self-Consistent Reaction Field) method was employed to account for the solvent effect of the acetonitrile solvent, and the electronic structures, electronic absorption and emission of Au(i-mnt)]22- in acetonitrile were obtained by the CIS calculations. The calculated absorption maximum, 315.5 nm, with the oscillator strength of 1.391 is assigned as an intraligand charge transfer(ILCT) transition. The phosphorescence with the wavelength of 436.2 nm arising from B3Au→1Ag is attributed to ILCT and metal to ligand charge transfer (MLCT) transitions, comparable to the emissive band around 500 nm of n-Bu4N]2Au(i-mnt)]2 in glass acetonitrile solution at 20 K in the experiment. Such a transition is described as an organ-ligand luminescent mechanism with metal decoration.