Dioxygen activation by Bi(III) compounds: Air oxidation of thiols to their disulfides

作者：Ioannou Panayiotis V^*

来源：Main Group Chemistry, 2013, 12(2): 125-138.

DOI：10.3233/MGC-130095

• Bismuth nitrate pentahydrate
• bis(dimethylarsinato)(nitrato)bismuth monohydrate
• thiols
• disulfides
• dioxygen activation

Bismuth nitrate pentahydrate, Bi(NO3)(3)center dot 5H(2)O, reacts with aliphatic and aromatic thiols giving trithiolates, Bi(SR)(3) and Bi(SAr)(3), some of them being catalytically active for the air oxidation of their thiols to disulfides. The process most likely involves activation of triplet dioxygen by Bi(III) to give Bi(V) esters [(RS)(3)BiO](x) and [(ArS)(3)BiO](x). These esters decompose intramolecularly to their disulfides and Bi(III) subthiolates (RS-BiO)(x)/(ArS-BiO)(x) which in the presence of excess thiols regenerate the trithiolates, repeating the cycle. Nitric acid, released from bismuth nitrate, may also be involved as an oxidant. Bis(dimethylarsinato)(nitrato)bismuth(III) monohydrate, (Me2AsO2)(2)Bi(NO3)center dot H2O, catalyzes the autoxidation of certain thiols to their disulfides. It acts by either forming Bi(III) trithiolates, as in the case of Bi(NO3)(3)center dot 5H(2)O or, when the cacodylate groups are not stripped off the Bi(III), by probably generating peroxynitric acid. The synthetic usefulness of these reagents are assessed and probable biochemical implications of these findings are discussed.

• 出版日期2013