Towards Understanding the Reactivity and Optical Properties of Organosilicon Sulfide Clusters

Abstract

We report the extension of the class of organotetrel sulfide clusters with further examples of the still rare silicon-based species, synthesized from RSiCl₃ with R=phenyl (Ph, I), naphthyl (Np, II), and styryl (Sty, III) with Na₂ S. Besides known [(PhSi)₄ S₆ ] (IV), new compounds [(NpSi)₄ S₆ ] (1) and [(StySi)₄ S₆ ] (2) were obtained, the first two of which underwent reactions with [AuCl(PPh₃ )] to form ternary complexes. DFT studies of cluster dimers helped us understand the differences between the habit of {Si₄ S₆ }- and {Sn₄ S₆ }-based compounds. Crystalline 1 showed a pronounced nonlinear optical response, while for intrinsically amorphous 2, the chemical damage threshold seems to inhibit a corresponding observation. Calculations within the independent particle approximation served to rationalize and compare electronic and optical excitations of [(RSi)₄ S₆ ] clusters (R=Ph, Np). The calculations reproduced the measured data and allowed for the interpretation of the main spectroscopic features.