Hydrothermal synthesis and crystal structure of a new lanthanum(III) coordination polymer with fumaric acid

Abstract

The title compound, poly[diaquatris(μ4-but-2-enedioato)(μ2-but-2-enedioic acid)dilanthanum(III)], [La2(C4H2O4)3(C4H4O4)(H2O)2]n, was synthesized by the reaction of lanthanum chloride pentahydrate with fumaric acid under hydrothermal conditions. The asymmetric unit comprises an LaIIIcation, one and a half fumarate dianions (L2−), one a half-molecule of fumaric acid (H2L) and one coordinated water molecule. Each LaIIIcation has the same nine-coordinate environment and is surrounded by eight O atoms from seven distinct fumarate moieties, including one protonated fumarate unit and one water molecule in a distorted tricapped trigonal–prismatic environment. The LaO8(H2O) polyhedra centres are edge-shared through three carboxylate bridges of the fumarate ligand, forming chains in three dimensions to construct the MOF. The crystal structure is stabilized by O—H...O hydrogen-bond interactions between the coordinated water molecule and the carboxylate O atoms, and also between oxygen atoms of fumaric acid