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

The green coloured micro-phenoxo, micro-chloro and micro-phenoxo, micro(1,1)-azido bridged complexes of formula [Ni2(L)(Cl)(H2O)] x (C2H5)2O, 1 x (C2H5)2O, and [Ni2(L)(N3)(H2O)] x CH3OH x H2O, 2 x CH3OH x H2O have been synthesized, where L3- is the deprotonated form of 2,6-bis[N-(2-hydroxybenzyl)-N-{2-(dimethylamino)ethyl}aminomethyl]-4-methylphenol, H(3)L. In the complexes, one nickel(II) center has distorted square pyramidal (tau = 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.