THE EFFICIENT CATALYSIS OF THE AUTOXIDATION OF THIOPHENOL BY A TETRADEHYDROCORRINATOCOBALT(III) COMPLEX
The oxidation of thiophenol was effectively catalyzed by dicyano-8,12-diethyl-1,2,3,7,13,17,18,19-octamethyltetradehydrocorrinatocobalt(III) ((CN)2Co(III)TDHC) in methanol containing small amounts of acetic acid and sodium cyanide at room temperature. The reaction was consistent with the sequence: (1) (CN)2Co(III)TDHC is reduced to Co(I) with thiophenol without participation of molecular oxygen; (2) the Co(I) species is oxidized to Co(II)TDHC by oxygen and acid; (3) the Co(II) species is oxidized to (CN)2Co(III)TDHC by the cooperation of oxygen and cyanide ion. The Co(III) species was repeatedly used at a rate of 3–5 cycle per second as an electron transport mediator.