氮化锇配合物离子[OsN(mnt)_2]^-的电子结构和光谱性质的理论研究

Theoretical Studies on Electron Structures and Spectroscopic Properties of Complex [OsN(mnt)_2]^-

理论研究了离子型配合物[OsN(mnt)2]-[mnt=S2C2(CN)2)]的电子结构和光谱性质,考察不同配体三价N、二硫氰烯S2C2(CN)2和金属Os的相互作用对光化学性质的影响.分别在B3LYP/LANL2DZ和CIS/LANL2DZ水平上优化了配合物的基态和激发态结构.与基态(1A1)相比,激发态(3A2)的Os≡N的键长缩短了0.0066nm,这与计算得到的频率增大一致,使用TD-DFT方法计算得到了配合物的吸收和发射光谱.计算得到的位于300nm(f=0.1497)和262nm(f=0.2890)的强吸收都来自1A1→1B1跃迁,分别指认为SC→Os≡N+CN和N+SC→Os≡N+CN的电子跃迁.最低能量的吸收位于446nm(f=0.0206)处,来自1A1→1B2的电子跃迁,指认为N→Os和N+SC→CN.计算得到配合物在气态的磷光发射位于678nm(A3A2→X1A1)处,而在丙酮溶液中则蓝移到了625nm处,跃迁属性不变,都是N→Os和S→Os的跃迁.

Electronic structures and Spectroscopic properties of nitridoosmium （Ⅵ） complex ion, [ OsN （mnt）2 ]^ - were studied theoretically, and the influence of interaction of the ligand [ three bond N and dithiolene S2C2 （CN）2] and the metal（ Os^Ⅵ） on the character of photochemistry was investigated. The structures of the complexes were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels for the ground states and excited states, respectively. The bond length of Os ≡ N bond is shorted by ca. O. 066 nm in the A3A2 excited state in comparison with the X^1A1 ground state, which is consistent with a higher vibration frequency of v（Os-N） in the excited state than that in the ground state. We obtain the excited energy and the character of the charge transition of the absorption and emission under TD-DFT calculation. The intense absorptions at 300 nm and 262 nm were attributed to SC→Os= N ＋ CN and N ＋ SC→Os ≡ N ＋ CN, respectively. The lowest energy absorptions at λmax = 446 nm were assigned as N→Os and N^ ＋ SC→CN. The calculated phosphorescence emissions at λ max = 678 nm（A^3A2→X^1A1 ） were originated from N→Os and S→Os, the emission properties does not alter in the solvent acetonitrile. However, the emission blue-shifted to 625 nm.