Sulfur oxygenation of [Ni(btdt) < inf > 2 < /inf > ] < sup > 2- < /sup > by aerial oxidation under ambient conditions - Syntheses, crystal structures, and properties of [Bu < inf > 4 < /inf > N] < inf > 2 < /inf > [Ni(btdt) < inf > 2 < /inf > ] and [Bu < inf > 4 < /inf > N] < inf > 2 < /inf > [Ni(btdtO < inf > 2 < /inf > ) < inf > 2 < /inf > ]·H < inf > 2 < /inf > O ({btdt} < sup > 2- < /sup > = 2,1,3-benzenethiadiazole-5,6-dithiolate)

Abstract

[Bu 4N] 2[Ni(btdt) 2] (1) ({btdt} 2- = 2,1,3-benzenethiadiazole-5,6-dithiolate) was synthesized by treating one equivalent of NiCl 2·6H 2O with two equivalents of H 2btdt in MeOH in the presence of NaOH under nitrogen, and then obtaining a precipitate by adding tetrabutylammonium bromide. When the same reaction is carried out under ambient conditions, it yields the trans-disulfinate complex [Bu 4N] 2[Ni(btdtO 2) 2]·H 2O (2) along with complex 1. Complex 1 crystallizes in the triclinic space group P$\bar {1}$, whereas complex 2 crystallizes in the monoclinic space group C2/c. The Ni II ion, coordinated with four sulfur atoms present in complex 1, shows almost square-planar geometry, but trans-disulfinate complex 2 shows distorted square-planar geometry around the Ni II ion with a nonplanar molecular structure. Oxygen atoms of the sulfinates are involved in C-H⋯O and O-H⋯O hydrogen-bonding interactions, which might be important factors for the nonplanarity of complex 2. Complex 1 undergoes a reversible oxidation (ΔE = 0.09 V) at E 1/2 = +0.22 V vs. Ag/AgCl and an irreversible oxidation at +0.77 V, whereas complex 2 shows quasi-reversible oxidation at E 1/2 = +0.50 V vs. Ag/AgCl in acetonitrile solution. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.