Magnetic properties of some tridentate Schiff-base-manganese(II) complexes

Abstract

A series of manganese(II) chelates of stoicheiometry [MnL] have been synthesized, where LH₂ is a dibasic tridenate Schiff base formed between a 5-substituted salicylaldehyde and either a 5-substituted β- hydroxyaniline or anthranilic acid. The complexes are extremely susceptible to oxidation in solution but stable when dry. Some of the complexes were isolated as hemihydrates and others as mixed hydrate- ethanolates. Magnetic susceptibility measurements over the temperature range 80-300°K have been made for a number of the complexes. In some cases the magnetic moments at room temperature are reduced slightly from the spin-only S = 5/2 value and show θ values of c. 15-50°K. The results can be interpreted in terms of binuclear or polynuclear structures with very small values of the exchange integral J. Comparisons between observed and calculated data are not as good as those shown in related VO²⁺, Ni^II, Cu^II, and Fe^III systems for which X-ray crystal structures are known.