Syntheses and characterization of ferrocenylthiocarboxylate-containing coordination compounds for nonlinear optics

Four metal-organic coordination compounds containing ferrocenylthiocarboxylate components, [Cd2(η2-SOCFc)2(η1-μ2-SOCFc)2(4,4′-bpy)]n (1), [Cd(SOCFc)2(tmp)]n (tmp = 4,4′-trimethylene-dipyridine) (2) [Zn(SOCFc)2(2,2′-bpy)] (3), and {[Hg(SOCFc)2(phen)] · (0.5CH3OH)} (4) (Fc = (η5-C5H5)Fe(η5-C5H4)), have been prepared in search of good nonlinear optical (NLO) materials. Investigation of the NLO properties shows that Hg-containing compound 4 exhibits very strong third-order NLO absorptive and refractive effects. The NLO absorptive coefficient α2 value (2.11 × 10−10 m W−1) is larger than those of all the reported ferrocenylcarboxylate-containing coordination compounds and comparable to the well-performing Hg-containing complexes. Additionally, we further analyzed their NLO behaviors through studying electrochemical properties of the four compounds.