二正丁基二硫代氨基甲酸锌配合物的量子化学研究

The Quantum Chemistry Studies on Zinc Complex with Dibutlydithiocarbamate

The geometric configurations of binuclear Zinc( complex Zn2[(n-Bu)2NCSS]4 and the ligand Na[(n-Bu)2 NCSS] have been optimized by B3LYP quantum chemical method. The electronic structures have been performed by density functional theory at B3LYP/6-31G* level. The electronic spectrums of the complex and ligand were calculated by ZINDO/S-CIS method. It is indicated from the calculation that: (1) The coordination effect of bridging ligand is bigger than that of chelating one, and the bridging ligands also translate more charge to Zn than the chelating one. (2) The calculated results about electronic spectrums are similarly to experimental measurement, and farther explain that absorption band at λ=267 nm of complex is assigned to two n → π* transitions :one arising from the bridging ligands and the another mainly arising from the chelating ligands;but absorption band at λ=236 nm of complex is assigned to π → π* transition which the electron mainly translates from the bridging ligands to the chelating ligands. (3) By consideration of delocalization and polar effects in coordination, the charge transfer from ligand to metal decreases the π-π and p-π conjugation effects in the chromophore group NCS2 and to increase the energy needed for the π → π* and n → π* transitions, and results in the absorption bands shifting towards the short wavelength direction.

The geometric configurations of binuclear Zinc(II) complex Zn(2)[(n-BU)(2)NCSS](4) and the ligand Na[(n-Bu)(2) NCSS] have been optimized by B3LYP quantum chemical method. The electronic structures have been performed by density functional theory at B3LYP/6-31G* level. The electronic spectrums of the complex and ligand were calculated by ZINDO/S-CIS method. It is indicated from the calculation that: (1) The coordination effect of bridging ligand is bigger than that of chelating one, and the bridging ligands also translate more charge to Zn than the chelating one. (2) The calculated results about electronic spectrums are similarly to experimental measurement, and farther explain that absorption band at lambda=267 nm of complex is assigned to two n -> pi transitions :one arising from the bridging ligands and the another mainly arising from the chelating ligands;but absorption band at lambda = 236 nm of complex is assigned to pi -> pi* transition which the electron mainly translates from the bridging ligands to the chelating ligands. (3) By consideration of delocalization and polar effects in coordination, the charge transfer from ligand to metal decreases the pi - pi and p-pi conjugation effects in the chromophore group NCS, and to increase the energy needed for the pi - pi* and pi - pi* transitions, and results in the absorption bands shifting towards the short wavelength direction.