Crystal structure of a mixed-ligand terbium(III) coordination polymer containing oxalate and formate ligands, having a three-dimensional fcu topology

Abstract

The title compound, poly[(μ3-formato)(μ4-oxalato)terbium(III)], [Tb(CHO2)(C2O4)]n, is a three-dimensional coordination polymer, and is isotypic with the LaIII, CeIIIand SmIIIanalogues. The asymmetric unit contains one TbIIIion, one formate anion (CHO2−) and half of an oxalate anion (C2O42−), the latter being completed by application of inversion symmetry. The TbIIIion is nine-coordinated in a distorted tricapped trigonal–prismatic manner by two chelating carboxylate groups from two C2O42−ligands, two carboxylate oxygen atoms from another two C2O42−ligands and three oxygen atoms from three CHO2−ligands, with the Tb—O bond lengths and the O—Tb—O bond angles ranging from 2.4165 (19) to 2.478 (3) Å and 64.53 (6) to 144.49 (4)°, respectively. The CHO2−and C2O42−anions adoptμ3-bridging andμ4-chelating-bridging coordination modes, respectively, linking adjacent TbIIIions into a three-dimensional 12-connected fcu topology with point symbol (324.436.56). The title compound exhibits thermal stability up to 623 K, and also displays strong green photoluminescence in the solid state at room temperature.