Electrochemical and Mössbauer studies on iron(II) complexes of a new series of entwining ligands: stabilization of uni- and zero-valent oxidation states

Abstract

Iron(II) complexes of 1,10-phenanthroline ligands (L) disubstituted at the 2,9 positions or monosubstituted at the 2 position by phenyl moieties having ortho substituents were prepared and investigated by spectral, Mössbauer and electrochemical techniques. The 2,9-di(o-alkoxyphenyl)-1,10-phenanthroline ligands readily form stable bis complexes [FeL₂]²⁺. Owing to the particular entwining arrangement of the co-ordinating sub-units, their topography together with the large tetrahedral distortions they induce, and the influence of the alkoxy group at the ortho position of the phenyl ring of the ligand system, these iron(II) complexes display novel electrochemical properties and exceptional stability of their lower oxidation states.