Electronic properties of mixed valence iron(II,III) dinuclear complexes with carboxylate bridges

Mixed valence dinuclear iron(II,III) complexes of the type [Fe2L2(H2O)(4)](NO3)(H2O)(3), where L is the dianion of a Schiff base ligand derived from alpha-amino acids (glycine and L-isolecine) and 5-bromosalicylaldehyde, have been prepared and characterised using different spectroscopic methods, magnetic susceptibility, conductivity, and electrochemical measurements. The mixed valence iron complexes can be described as hexacoordinated species, in which the metal ion is surrounded by water molecules, the salicylidenimine ligand and two bridging carboxylate groups. The presence of bromine as a substituent in the salicylaldehyde ring stabilises the mixed valence species. (c) 2006 Elsevier Ltd. All rights reserved.