Selective oxidation of organic sulfides to sulfoxides using sugar derived cis-dioxo molybdenum(VI) complexes: kinetic and mechanistic studies

Six Mo(VI) complexes of 4,6-O-ethylidene-beta-D-glucopyranosylamine derived ligands have been used for the selective oxidation of five organic sulfides to corresponding sulfoxides. The structure of a new sulfide [(((2-(phenylthio)phenyl)imino)methyl)naphthalen-2-ol] (S5) and its corresponding sulfoxide (SO5) has been established using single crystal X-ray diffraction studies along with other routine analytical techniques. The yields of sulfoxides were calculated using HPLC and one of the catalysts was recycled five times without any appreciable loss in its activity. Kinetic studies on sulfoxide formation was performed on compound S5 using UV-visible spectroscopy, which suggested overall first order kinetics. A plausible mechanism for sulfide oxidation has been proposed based on our findings and previous literature reports.