Mononuclear Mn(III) and dinuclear Mn(III, III) Schiff base complexes: Influence of π–π stacking on magnetic properties

Abstract

Synthesis of a mononuclear Mn(III) (1) and a dinuclear Mn(III,III) (2) complex of a tetradentate N2O2 donor Schiff base ligand with ancillary carboxylate ligands are reported. Complex 1 crystallizes in the monoclinic space group C2/c, complex 2 in the triclinic space group P-1. In both complexes the central Mn(III) ions are hexacoordinated having a distorted octahedral MnN2O4 coordination environment. Intermolecular hydrogen bonding and strong π–π stacking in both 1 and 2 leads to dimerization of 1 and formation of a syn–anti one-dimensional chain for 2. Magnetic properties of 1 and 2 are reported. Both complexes show very weak intermolecular antiferromagnetic interaction. Most interestingly the major contribution for the exchange coupling arises from a superexchange pathway involving π–π interaction.