Mixed bridged dinuclear Ni(II) complexes: synthesis, structure, magnetic properties and DFT study

Abstract

The green coloured μ-phenoxo, μ-chloro and μ-phenoxo, μ_1,1-azido bridged complexes of formula [Ni₂(L)(Cl)(H₂O)]·(C₂H₅)₂O, 1·(C₂H₅)₂O, and [Ni₂(L)(N₃)(H₂O)]·CH₃OH·H₂O, 2·CH₃OH·H₂O have been synthesized, where L³⁻ is the deprotonated form of 2,6-bis[N-(2-hydroxybenzyl)-N-{2-(dimethylamino)ethyl}aminomethyl]-4-methylphenol, H₃L. In the complexes, one nickel(II) center has distorted square pyramidal (τ = 0.18 and 0.15) and other one has distorted octrahedral geometry. Both the complexes display a couple of one electron anodic responses near 0.70 and 1.10 V. Complexes 1 and 2 show weak antiferro and ferromagnetic interactions respectively. The calculated J value using broken symmetry DFT method is consistent with the experimentally observed value. Moreover, the calculation also reveals that the antiferromagnetic interaction between the Ni(II) centers takes place via the phenoxo bridge while that of ferromagnetic interaction is through the azido and chloro group. The presence of competitive interaction in the molecule reduces the overall magnetic behavior of the complex.