C-H bond activation and S-atom transfer from cobalt(III) thiolate and isothiocyanate complexes.

The cobalt phenylthiolate complex, cis,mer-(PMe3)3Co(CH3)2SPh, was found to undergo competitive two-electron ethane reductive elimination and C-H bond cyclometallation. The thiophenolato bound cobaltacycle was generated via C-H bond oxidative addition to a five-coordinate intermediate followed by rapid methane elimination. A related cobalt isothiocyanate complex, cis,mer-(PMe3)3Co(CH3)2NCS, was also prepared and found to perform ethane elimination and S-atom transfer to yield trimethylphosphine sulfide. This rare example of S-atom donation from a isothiocyanate was characterized by NMR and GC-MS analysis, with cis,mer-(PMe3)3Co(CH3)2CN identified as one of the cobalt based products.