Magnetic properties and Mössbauer spectra of some terdentate Schiff-base–iron(III) halide complexes

Abstract

The preparation and magnetic susceptibilities over the temperature range 80–300°K of a series of iron(III) chloro- and bromo-complexes with terdentate Schiff bases are reported. The magnetic data indicate polynuclear structures and have been interpreted by use of the spin–spin exchange theory assuming both binuclear and long linear chain models. The binuclear configuration leads to the best fits of the data in most cases and values of the exchange integral, J, are found to be in the range –7·0 to –10·5 cm.^–1. The Mössbauer spectra of several of the complexes have been measured at 298°, 78°, and 4·2 °K and have been compared with those for the related binuclear complex with a quadridentate Schiff base [Fe salen Cl]₂. The spectra suggest that some of the complexes might possess a similar binuclear structure whereas others probably contain iron atoms in non-equivalent sites.