Peculiar Magnetic Transition Behaviour Around 208 K in One-dimensional Nickel(III) Chain Complex [1-(4′-Vinylbenzyl)pyridinium][Ni(mnt)2] (mnt2− = Maleonitriledithiolate)

A new ion-pair complex, [VBzPy][Ni(mnt)2], where [VBzPy]+ = 1-(4′-vinylbenzyl)pyridinium and mnt2− = maleonitriledithiolate, has been synthesized. The cations and anions stack into completely separated columns and Ni(III) ions form a uniformly spaced one-dimensional (1-D) zigzag chain within a [Ni(mnt)2]− column in solid state. Magnetic susceptibility and DSC measurements revealed that there exists a first-order phase transition at approximately 208 K.