Abstract: The electronic spectra in several solvents, complete IR spectra in powder state and quantum chemical theoretical studies of the title complex Ni(mnt)(dmbpy) were reported in this paper. Geometry optimization calculations by PM3 method show that the complex is of a planar structure with the symmetry C_2vand the spin triplet as the ground state. The CIcalculations by ZINDO/S method proved that the bands (450-550 nm) in the visible region in the observed spectra belong to the charge transfer from the ligand dmbpy to another ligand mnt^2-(LL'CT) essentially. Anew method for analyzing vibrational spectra of complicated molecule is established by PM3 calculations. The essential of this method is to give main fixed points and pivotal vibrational units in assignment for each normal mode. Anew vibration type describing heaving along the specified direction was defined by the symbol η(X).

Key words: Nickle(Ⅱ) complex of dithiolate and bipyridine, Infrared spectrum, Electronic spectra, New method to analyze vibrational spectra