Probing the structural features and magnetic behaviors in dinuclear cobalt(II) and trinuclear iron(III) complexes

Abstract

The coordination chemistry of the tetradentate N2O2-type ligand 2-[Bis(2-hydroxybenzyl)aminomethyl]pyridine (H2L) has been investigated with cobalt(II) and iron(III) ions. Synthesis, structure and detailed magnetic study of dinuclear Co(II) and trinuclear iron(III) complexes were reported. The complexes: [Co2(L)2] (1), [Fe3(µ3-O)(µ2-OH)(L)3]·2.5CH3CN (2) and [Fe3(µ3-O)(µ2-OH)(L)3]·2DMA. Et2O (3) have been structurally analyzed by single-crystal X-ray diffraction. In Co(II) complex two Co(II) centres are bridged by a phenoxo group whereas in Fe(III) complexes, three metal centres are connected through µ2-phenoxo, µ2-hydroxo and µ3-oxo bridges. Analysis of the temperature dependent magnetic susceptibility of compound 1 indicates that the phenoxo, hydroxo and oxo bridge mediate weak antiferromagnetic interactions with a coupling constant JCo-Co = − 0.89 cm−1. The magnetic study of trinuclear Fe(III) complex (compound 2) displays intra-metallic ferro- and antiferromagnetic exchange interactions through oxo, phenoxo and hydroxo bridges. Fitting to the curve revealed the parameters, J1 = 2.45 cm−1, J2 = − 0.65 cm−1 and g = 1.95.