Abstract
The title compound, {[La(2)(CH(3)COO)(2)(C(8)H(10)O(4))(2)(H(2)O)(4)]·2H(2)O} (n) or [La(2)(ac)(2)(e,a-cis-1,4-chdc)(2)(H(2)O)(4)]·2H(2)O, where ac is acetate and 1,4-chdc is cyclo-hexane-1,4-di-carboxyl-ate anion, is a binuclear lanthanum(III) complex. Each metal atom is deca-coordinated by four O atoms from two distinct 1,4-chdc(2-) ligands, four O atoms from three acetate groups and two O atoms from coordinated water mol-ecules to form a distorted bicapped square-anti-prismatic geometry. Two non-coordinated water mol-ecules are also present in the formula unit. The most remarkable feature of this compound is that it possesses a only cis conformation for cyclo-hexane-1,4-di-carb-oxy-lic acid, although the raw material consists of a mixture of cis and trans isomers. The μ(3)-η(2):η(2) coordination mode of the bridging acetate group and the flexible di-carboxyl-ate fragments of 1,4-chdc(2-) results in the formation of infinite two-dimensional lanthanide-carboxyl-ate layers within the crystal structure. The directionality of strong inter-molecular O-H⋯O and weak C-H⋯O inter-actions provides robustness to the layers, which leads to the construction of a three-dimensional supra-molecular network. The crystal studied was refined as a two-component twin.