Identification of lowest excited states in the organometallic iron-nitrile complexes

Abstract

Electronic absorption spectra for the complexes [CpFe(dppe)NC-R]PF6 R = CH2-C6H4-ON3P3(OC 6H4t-Bu)5 (1), R = CH2-C6H4-OH (2) and R = CH3 (3) in different solvents have been measured. The two absorption bands at the lowest energy value for (1) and (2) are assigned to a metal - ligand charge - transfer transition (MLCT) on the basis of the solvent effect and extended Hückel MO calculations. The possible implications of a low-lying excited states in these complexes are discussed.