Bis(μ2-benzoato-κ2 O,O′)bis(benzoato-κO)bis(ethanol-κO)bis(μ3-hydroxido)hexakis(μ-pyrazolato-κ2 N,N′)hexacopper(II) ethanol disolvate

Abstract

Trinuclear copper–pyrazolate entities are present in various Cu-based enzymes and nanojar supramolecular arrangements. The reaction of copper(II) chloride with pyrazole (pzH) and sodium benzoate (benzNa) assisted by microwave radiation afforded a neutral centrosymmetric hexanuclear copper(II) complex, [Cu6(C7H5O2)4(OH)2(C3H3N2)6(C2H5OH)2]·2C2H5OH. Half a molecule is present in the asymmetric unit that comprises a [Cu3(μ3-OH)(pz)3]2+ core with the copper(II) atoms arranged in an irregular triangle. The three copper(II) atoms are bridged by an O atom of the central hydroxyl group and by three bridging pyrazolate ligands on each of the sides. The carboxylate groups show a chelating mode to one and a bridging syn,syn mode to the other two CuII atoms. The coordination environment of one CuII atom is square-planar while it is distorted square-pyramidal for the other two. Two ethanol molecules are present in the asymmetric unit, one binding to one of the CuII atoms, one as a solvent molecule. In the crystal, stabilization arises from intermolecular O—H...O hydrogen-bonding interactions.