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.