The Syntheses and Crystal Structures of the First Disiloxane-1,3-dithiol and Its Cadmium Complex

The silicon-sulfur compound bis-1,3-[di(2,6-diisopropylphenoxy)]disiloxane-1,3-dithiol was obtained from silicon disulfide and 2,6-diisopropylphenol in a reaction catalyzed by imidazole or 4-(dimethylamino)pyridine (DMAP). The disiloxane-1,3-dithiol is produced in a low yield but in a repeatable manner and can be isolated as colorless crystals. The X-ray crystal structure of the compound reveals a linear or close-to-linear Si-O-Si angle and a mutual trans position of the two hydrosulfido groups. The compound forms a chelating mononuclear complex with cadmium ions. In the complex, the sulfido groups adopt a cis conformation, and the Si-O-Siangle deviates from linearity. The molecular structure of the compound is discussed on the basis of DFT calculations.