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

Marisol Ledezma-Gairaud,Leslie W Pineda

doi:10.1107/s2414314619011908

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.

Highlights

Trinuclear copper–pyrazolate entities are present in various Cu-based enzymes and nanojar supramolecular arrangements
Half a molecule is present in the asymmetric unit that comprises a [Cu3(3-OH)(pz)3]2+ core with the copper(II) atoms arranged in an irregular triangle
Two ethanol molecules are present in the asymmetric unit, one binding to one of the CuII atoms, one as a solvent molecule

Summary

DÁ Á ÁA

The carboxylate groups of the two benzoate anions present in the asymmetric unit bind in different fashions. A chelating mode by carboxylate atoms O3 and O4 is realised to bind to Cu1 whereas a syn, syn mode bridging Cu2 and Cu3 of the symmetry-related part is realised for O1 and O2 The latter connectivity is found in various polymeric copper(II) carboxylates (Casarin et al, 2005). In the crystal structure of the title compound, further stabilization arises from intermolecular O—HÁ Á ÁO hydrogen bonds This way, the 3-OH group and the oxygen atom O8 of the solvate ethanol molecule, the OH group of the solvate ethanol molecule and the benzoate oxygen atom O4, and the OH group of the coordinating ethanol molecule and the O4 atom of the benzoate ligand are connected (Table 2, Fig. 4)

Synthesis and crystallization

Data collection Diffractometer Absorption correction

Data collection

Special details