Sulfur oxygenation of [Ni(btdt) _2] ~(2-) by aerial oxidation under ambient conditions - Syntheses, crystal structures, and properties of [Bu _4N] _2[Ni(btdt) _2] and [Bu _4N] _2[Ni(btdtO _2) _2]·H _2O ({btdt} ~(2-) = 2,1,3-benzenethiadiazole-5,6-dithiolate)

摘要

[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$ar {1}$, 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.