Second order non-linear optical activity of arsenic and antimony dithiolene complexes.

Synthesis and characterization of dithiolene complexes of arsenic and antimony in trivalent state have been reported. A four coordinated structural motif results in a ladder like arrangement in the arsenic complex due to the inter-anionic As-S interaction which is replaced by Sb-π interaction with the counter cation in the solid state structure of the similar antimony complex. Electronic structure calculations on ground state geometries and the time-dependent density functional theoretical calculations were performed in order to characterize the absorption spectra incorporating solvent effects. Notably, both the complexes display intense second order optical non-linearity as has been determined using hyper-Rayleigh scattering technique in dichloromethane solution and the results are corroborated by DFT calculations.