Crystal structure of poly[diaqua(μ-2-carboxyacetato-κ3O,O′:O′′)(2-carboxyacetato-κO)di-μ-chlorido-dicobalt(II)]

Abstract

The asymmetric unit of the title polymer, [Co2(C3H3O4)2Cl2(H2O)2]n, comprises one CoII atom, one water molecule, one singly deprotonated malonic acid molecule (HMal−; systematic name 2-carboxyacetate) and one Cl− anion. The CoII atom is octahedrally coordinated by the O atom of a water molecule, by one terminally bound carboxylate O atom of an HMal− anion and by two O atoms of a chelating HMal− anion, as well as by two Cl− anions. The Cl− anions bridge two CoII atoms, forming a centrosymmetric Co2Cl2 core. Each malonate ligand is involved in the formation of six-membered chelate rings involving one CoII atom of the dinuclear unit and at the same time is coordinating to another CoII atom of a neighbouring dinuclear unit in a bridging mode. The combination of chelating and bridging coordination modes leads to the formation of a two-dimensional coordination polymer extending parallel to (001). Within a layer, O—Hwater...Cl and O—Hwater...O hydrogen bonds are present. Adjacent layers are linked through O—H...O=C hydrogen bonds involving the carboxylic acid OH and carbonyl groups.

Keywords

• crystal structure
• malonate
• cobalt
• coordination polymer