Crystal structure of poly[tetra-μ-chlorido-tetrachloridobis(μ3-4,4′-bi-1,2,4-triazole-κ3N1:N2:N1′)(μ-4,4′-bi-1,2,4-triazole-κ3N1:N1′)tetracopper(II)]

Abstract

The title Cu2+–chloride coordination polymer with the 4,4′-bi-1,2,4-triazole ligand (btr), [Cu4Cl8(C4H6N6)3]n, crystallizes in the non-centrosymmetric orthorhombic space group Fdd2. The two independent Cu2+ cations adopt distorted square-pyramidal geometries with {Cl2N2+Cl} coordination polyhedra. The metal atoms are bridged by μ-Cl anions forming left- and right-handed helical chains of sequence [–(μ-Cl)CuCl–]n along the c-axis direction. In the perpendicular directions, the btr ligands act in μ- and μ3– coordination modes in a 2:3 ratio. The μ-btr bridges connect neighboring helices of the same handedness, whereas the μ3-btr ligands link the helices of opposite handedness, leading to a racemic three-dimensional framework. The structure is consolidated by weak C—H...Cl and C—H...N interactions.

Keywords

• crystal structure
• 4,4′-bi-1,2,4-triazole
• metal–organic frameworks
• copper(II) complexes