Mechanism of oxygenation of aryl methyl and diaryl sulphoxides by peroxomonophosphoric acid

Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)–polypyridyl complexes

“…The other aryl methyl sulfoxides used in this study were prepared from the corresponding sulfides according to the literature procedures. 56,57 All the sulfoxides were purified by vacuum distillation/recrystallization from suitable solvents. The physical constants of the sulfoxides were found to agree with literature values.…”

A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non‐linear Hammett

“…At the same time, they retard the nucleophilic attack of OH À on the sulfoxide cation radical (Eqn 5). Conversely, the EWGs while retarding the electron transfer (Eqn 4) not only exert an accelerating effect on the nucleophilic attack of H 2 O (Eqn 5) but also stabilize the intermediate (5) in the mechanism. From the observed increase in rate with EWG one could expect a change in rate determining step from electron transfer to nucleophilic attack, by changing the substituents from electron donating to electron withdrawing groups.…”

“…[3] But still they resemble organic sulfides in many oxidation reactions. [4][5][6] Some of the phenylsulfinyl compounds have found to possess high therapeutic effects. They are used for combating parasitic disorders with broad spectrum of action, treating Alzheimer's disease [7] and enhancing memory activities.…”

Biologically relevant chemical properties of peroxymonophosphate (O3POOH)

“…30 We observe that, DMSO, glycine, and the indole-containing amino acid tryptophan do not cause substantial decomposition of peroxymonophosphate in neutral aqueous buffer. Others have reported reactions of peroxymonophosphate with sulfoxides and indoles; 31,32 however, these earlier studies were conducted under conditions where the protonated species H 3 PO 5 was predominant. In contrast, with pK a values of 1.0, 5.5, and 12.8, peroxymonophosphate exists primarily as the dianion under the conditions of our experiments (pH 7).…”

“…In contrast, with pK a values of 1.0, 5.5, and 12.8, peroxymonophosphate exists primarily as the dianion under the conditions of our experiments (pH 7). 20,32 A number of studies show that the reactivity of peroxymonophosphate is pH-dependent, increasing at lower pH values as the oxygens become increasingly protonated. 25,30,31 A most striking difference between H 2 O 2 and peroxymonophosphate, is revealed by our observation that the H 2 O 2 -destroying enzyme catalase does not decompose peroxymonophosphate.…”