Crystal structure of a chloride-bridged copper(II) dimer: piperazine-1,4-dium bis-(di-?-chlorido-bis[(4-carboxypyridine-2-carboxyl-ato-?2N,O2)chlorido-cuprate(II)].

ABSTRACT: Crystals of a new dimeric chloride-bridged cuprate(II) derived from pyridine-2,4-di-carb-oxy-lic acid were obtained solvothermally in the presence of piperazine and hydro-chloric acid. The crystal structure determination of the title salt, (C4H12N2)[Cu2(C7H4NO4)2Cl4], revealed one of the carboxyl groups of the original pyridine-2,4-di-carb-oxy-lic acid ligand to be protonated, whereas the other is deprotonated and binds together with the pyridine N atom to the CuII atom. The coordination environment of the CuII atom is distorted square-pyramidal. One of the chloride ligands bridges two metal cations to form a centrosymmetric dimer with two different Cu-Cl distances of 2.2632?(8) and 2.7853?(8)?Å, whereby the longer distance is associated with the apical ligand. The remaining chloride ligand is terminal at one of the basal positions, with a distance of 2.2272?(9)?Å. In the crystal, the dimers are linked by inter-molecular O-H?O hydrogen bonds, together with N-H?O and N-H?Cl inter-actions involving the centrosymmetric organic cation, into a three-dimensional supra-molecular network. Further but weaker C-H?O and C-H?Cl inter-actions consolidate the packing.

SUBMITTER: Inah BE 

PROVIDER: S-EPMC5290575 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature