Abstract: The syntheses and characterization of novel biferrocene trinuclear complexes of Schiff base ligand, S-methyl-N-(ferrocenyl-1-methyl methylidene)dithiocarbazate [hereafter abbreviated as HL (1)], are described. The X-ray diffraction studies have established the structures of PdL₂(3) and CuL₂ (4). The geometry of Pd(Ⅱ) in (3) is close to a square plane and in the novel cis-configuration the two ferrocene moieties are in cis configuration, while that of Cu(Ⅱ) in (4) is close to a tetrahedral configuration. The electrochemical measurements suggested that the square planar configuration of Ni(Ⅱ) and Pd(Ⅱ) moieties can effectively transmit the redox effects of the ferrocene moieties, while the tetrahedral configuration of the Cu(Ⅱ) complex can not transmit the redox effects. The degenerate four wave mixing (DFWM) measurements showed that the complexes exhibit obviously nonlinear optical (NLO) response. The magnitude of their third order NLO susceptibility can be explained by their structure and electrochemical properties.

Key words: Electrochemistry, cis-Configuration biferrocene, Third-order nonlinear optical property