Strong antiferromagnetic interaction in μ-Oxo-bridged diiron(III) complex of pyridoxal Schiff base ligand

Dinuclear and mononuclear pyridoxal Schiff base complexes, specifically [{FeL} ₂ ( µ -O)]·2.2H ₂ O ( 1 ) and [NiL’(H ₂ O)]·2H ₂ O ( 2 ) (where L ^2– is the dianion of tetradentate Schiff base derived from pyridoxal and ethylenediamine, and L’ ^2– is the dianion of pentadentate Schiff base ligand formed from pyridoxal and N -(2-aminoethyl)propane-1,3-diamine) have been synthesized and characterized by elemental analysis, FT-IR, and mass spectrometry. The crystal structures of these complexes were determined using single crystal X-ray diffraction. The Fe atoms in complex 1 exhibit a distorted square pyramidal coordination geometry, while Ni atom in complex 2 displays a distorted octahedral geometry. Experimental magnetic investigation of complex 1 indicated a strong antiferromagnetic coupling between the two Fe(III) centers and a paramagnetic behavior of an octahedral Ni(II) complex 2 with two unpaired electrons. Density functional theory (DFT) calculations were performed, and the calculation results were compared with the experimental structural and magnetic characteristics of the complexes.