金属桥联双二茂铁配合物的结构与三阶非线性光学性质研究

Structure and Third - order Optical Property——Studies on Metal Bridged Biferrocene Complexes

三种金属桥联双二茂铁的三核配合物的合成、结构、电化学及三阶非线性光学性质,通过四圆X射线衍射测定,确定了铜配合物的晶体结构.铜配合物为高度畸变的平面四边形构型.双二茂铁处于顺式结构,这种结构由茂环间的π-π相互作用而变得稳定.研究表明,它们的结构、电化学性质及三阶非线性光学性质三者有密切的内在联系.平面型金属配合物桥联双二茂铁体系中电子离域程度高,在电化学上表现为两步连续单电子氧化过程,其三阶非线性光学效应较强,变形四面体型铜配合物桥联双二茂铁只有一个氧化还原过程,其三阶效应也较低.

A series of metal bridged biferrocene trinuclear complexes derived from Schiff base ligand, S - benzyl - N - (ferrocenyl - 1 - methylmethylidene) dithio carbazate (here after abbreviated as HL) have been synthesized and spectroscopically characterized. Single crystal structure analysis for the nickel complex, NiL2, palladium complex, PdL2 and copper complex, CuL2 revealed that the Schiff base ligand acted as a singly negtively charged bidentate and coordinated to the metal atom via the mercapto sulphur and β - nitrogen atoms. The coordination geometry of nickel atom and the palladium atom is close to square planar configuration forming an extensive electron delocalization system. The two ligands coordinated to the metal atom in a novel cis- configuration with the two ferrocene moieties on the same side. Detailed structure analysis show that the novel cis - configuration is stabilized by the intramolecular π -π stack interaction between the two acetylcyclopantadienyl rings. The coordination geometry of copper atom in CuL2 is closed to tetrahedral configuration. The electrochemical measurements of the three complexes suggest that square planar configuration of the Ni(Ⅱ) and Pd(Ⅱ) moieties can effectively transmit the redox effects of the ferrocene moieties, while the tetrahedral configuration of Cu(Ⅱ) complex cannot. The results also show that the complexes NiL2, PdL2 exhibit higher third - order nonlinear response.