Hydration of Nitriles to Amides by Thiolate-Bridged Diiron Complexes

A series of nitrile-coordinating complexes [Cp*Fe(μ-SEt)RCN]2[PF6]2 (1, R = alkyl, aryl, vinyl, amine) have been obtained by the reaction of [Cp*Fe(μ-SEt)MeCN]2[PF6]2 (1a) with various nitriles in acetone. Complexes 1 can realize the hydration of a nitrile ligand under ambient conditions. Complexes [Cp*Fe(μ-SEt)2(μ-η1:η1-NH(O)CR)FeCp*][PF6] (2) were successfully isolated as intermediates during the hydration process, with 2b and 2e (R = CH2═CH and Et2N) being characterized by spectrometry and X-ray crystallography. Treatment of 2 with HBF4·Et2O in the presence of nitriles released corresponding amides 3. At the same time, the structural features of the [Fe2S2] scaffold were retained. These results confirmed that the hydration of nitriles was realized by cooperative interaction on diiron centers.