Abstract: The structure and electronic properties of 8-hydroxyquinolinato manganese(Ⅲ) complex(MnQ₃, Q=8-hydroxyquinolinato) were studied theoretically with density functional theory(DFT). The structure was optimized and the calculation results show that the manganese ion is coordinated with one nitrogen atom and one oxygen atom of 8-hydroxyquinolinato ligand. The average bond length of Mn—N is 0.2072 nm and that of Mn—O is 0.1887 nm, which were consistent with the crystallographic data. In addition, the molecular structure and electronic structural characteristics of the complex were analyzed. The contribution of Mn(Ⅲ) to the frontier molecular orbitals are significant, 28.53% to HOMO and 68.30% to LUMO. The electro-absorption spectrum of MnQ₃ was calculated by time-dependent density functional theory, the calculated results show that the two strong absorption peaks are at 756.8 nm and 532.7 nm respectively due to the charge transformation from intra-ligand to manganese(Ⅲ). From two-molecule system, the charge was transported from one complex to the neighbor one. The intermolecular interaction affects the composition of the frontier molecular orbital obviously.

Key words: 8-Hydroxyquinolinato mangnese complex, Absorption spectrum, Time-dependent density functional theory