Redox-active ferrocene-dithiolenes hybrid complexes showing switchable nonlinear optical properties

Abstract

Density functional theory(DFT) calculations were carried out to investigate the geometry structures, redox properties and second-order nonlinear optical(NLO) properties of ferrocene(Fc)-dithiolenes hybrid complexes. The switchable second-order NLO properties of these complexes are induced by the redox process. The oxidized process significantly affects the geometrical structures of the dithiolene moieties, that is, the embowed dithiolene moieties change into planar structures. It supports that the dithiolene moieties are the oxidized center. The βtot values of the cationic species are at least 4 and 10 times those of their corresponding parent complexes, respectively. Further, the time-dependent DFT calculation illustrates that the low-energy absorption(which is helpful for the large NLO response) is mainly assigned to intra-ligand charge transfer [π(ex-dithiolene)→π*(ex-dithiolene)]. These results suggest the potential use of the novel Fc-based dithiolenes complexes as versatile and fascinating NLO switching materials.