Catalytic Oxygenation of Organic Sulfides Using Diruthenium(II,III) Amidates

Catalytic oxygenation of organic sulfides has been proven to be a convenient and effective method to remove sulfur compounds from fossil fuels and to detoxify V-type agents and muster gas. Two new diruthenium(II,III) tetraamidate compounds, Ru₂(NHOCC(CH₃)₂)₄Cl (1) and Ru₂(NHOCCH₂CH₃)₄Cl (2) have been prepared and structurally characterized by X-ray crystallography. The activity in promoting sulfide oxygenation using simple green oxidants such as hydrogen peroxide (H₂O₂) and tert-butyl hydroperoxide (TBHP) was studied. UV-kinetics studies indicated that the initial rate of 1 and 2 is comparable to the previously studied diruthenium tetracarboxylates in promoting TBHP oxygenation of methyl phenyl sulfide (MPS). Using excess oxidant and CH₃CN as the solvent, organic sulfides MPS and diphenyl sulfide (PPS) were oxidized using 1 mol% of the catalytic species. Catalyst 1 was more effective than 2 in converting sulfides to sulfoxide under the same conditions. Fast conversion was achieved when the reactions were carried out in the solvent free conditions, and the major oxidation product was the sulfoxide.