A trinuclear anionic trifluoroacetato derivative of iron(II) containing a central O(–I) ligand

The reaction of Fe(CO)5 with CF3COOH/(CF3CO)2O, or with CF3COOH, in DMF at about 140 °C produces the colourless compound 1, [Fe(DMF)6][Fe3(μ3-O) (CF3COO)6(DMF)3]2, constituted by the [Fe(DMF)6]2+ cation and by two [Fe3(μ3-O)(μ2-CF3COO)6(DMF)3]− anions, with a triangular disposition of the three iron atoms, the central substantially coplanar oxygen atom being formulated as a singly charged anion O(–I) stabilized by complexation to iron(II).