X-ray photoelectron spectroscopy study of a cyclic hexanuclear cluster

We report on a study of a ferric-wheel system by X-ray photoelectron spectr oscopy. The sample investigated was a cyclic hexanuclear Fe(III) cluster en trapping an alkaline ion: [Li subset of Fe6L6]Cl, L=N(CH2CH2O)(3). The Fe3s and 2p photoelectron spectra recorded for the ferric wheel and other Fe co mpounds, where Fe hits the formal valence state 3+ or 2+, were compared. Un commonly spectral features of the 3s line were qualitatively explained. It seems that unlike the usual transition metal compounds the electron energy configuration in the cluster favors the population of a final state with hi gh-spin arrangement of electrons and a ligand hole. This could be due to co valency in such molecular compounds. (C) 2001 Elsevier Science B.V. All rig hts reserved.