Unusual metal-ligand charge transfer in ferrocene functionalized μ3-O iron carboxylates observed with Mossbauer spectroscopy

Temperature dependent Mossbauer studies of two ferrocenecarboxylate functionalized {Fe3O} complexes in solid state are reported. It was found that conjugation of ferrocene ring orbitals with the pi orbitals of the adjacent carboxylic group promotes a shift of electron density from the ferrocene Fe-II ion to the cyclopentadienide rings with pi-orbital character giving rise to a new type of mixed-valence compound. (C) 2016 Elsevier B.V. All rights reserved.