Synthesis, structures, and magnetic behavior of two high-spin binuclear Fe(III) complexes

Article abstract of DOI:10.1080/00958972.2011.586032

The reaction of 2-t-butyl-4-ethylphenol, formaldehyde, and 2-amino propanol or 3-amino-1-propanol at 2 : 2 : 1 provides N-(1-ethanol)-N,N-bis(3-t-butyl-5- ethyl-2-hydroxybenxyl)amine (H3L') and N-(3-amino-1-propanol)-N,N-bis(3-t-butyl- 5-ethyl-2-hydroxybenxyl)amine (H3L″), respectively. In the presence of Et3N, the reaction of FeCl3 6H2O and H3L′ or H3L″ gives dinuclear Fe(III) complexes [Fe₂L′₂] 1 and [Fe ₂L″₂] 2, respectively, which have been characterized by X-ray crystallography, magnetic measurements, and cyclic voltammetry (CV). Magnetic studies indicate significant antiferromagnetic coupling between the iron(III) centers for 1 and 2. The values obtained for the coupling constants (J) are -12.35 cm^-1 for 1 and -16.26 cm^-1 for 2. CVs of 1 and 2 reveal one reversible wave at -0.80 and -0.82 V versus AgCl/Ag, respectively, which can be ascribed to redox coupling of Fe^IIIFe ^II/Fe^IIIFe^III.