Synthesis, X-ray structures and magnetic properties of Ni(II) complexes of heteroaromatic hydrazone

Two binuclear double end-on azido bridged Ni(II) complexes, [Ni2L2(mu-(1,1)-N-3)(2)(N-3)(2)]center dot 2H(2)O (1a), and [Ni2L2(mu-(1,1)-N-3)(2)(N-3)(2)]center dot 4H(2)O (1b) having the same inner sphere, where L=((E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium, were synthesized from the same solution and characterized by single-crystal X-ray diffraction methods. Variable-temperature magnetic susceptibility measurements showed intra-dimer ferromagnetic coupling between Ni(II) ions. The ferromagnetic coupling is supported by the broken-symmetry DFT calculations, with the level of theory chosen based on a benchmark study on 19 additional structurally related binuclear Ni(II) complexes. The role of water molecules in crystals of 1a and 1b is explained by DFT based energy decomposition analysis. (C) 2020 Elsevier Ltd. All rights reserved.