Crystal structure of an unknown solvate of bis(tetra-n-butylammonium) [N,N′-(4-trifluoromethyl-1,2-phenylene)bis(oxamato)-κ4O,N,N′,O′]nickelate(II)

Abstract

In the title compound, [N(C4H9)4]2[Ni(C11H3F3N2O6)] or [N(n-Bu)4]2[Ni(topbo)] [n-Bu = n-butyl and topbo = 4-trifluoromethyl-1,2-phenylenebis(oxamate)], the Ni2+ cation is coordinated by two deprotonated amido N atoms and two carboxylate O atoms, setting up a slightly distorted square-planar coordination environment. The [Ni(topbo]2− anion lies on a twofold rotation axis. Due to an incompatibility with the point-group symmetry of the complete molecule, orientational disorder of the CF3 group is observed. The tetrahedral ammonium cations and the anion are linked by weak intermolecular C—H...O and C—H...F hydrogen-bonding interactions into a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as plausible solvent molecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent molecule.

Keywords

• crystal structure
• nickel(II)
• oxamate ligand
• non-symmetric compound
• disorder
• SQUEEZE procedure