Structural characterization of lanthanide coordination polymers assembled from V-shaped 4,4′-oxybis(benzoate) ligand

Hydrothermal reaction of lanthanide(III) (Nd, Er and Tm) chloride with sodium salt of 4,4′-oxybis(benzoic) acid (H2oba) leads to the formation of two types of monocrystals: prismatic [Nd(Er)(Hoba)(oba)(H2O)2]·0.8H2O (1, 2) and plate-shaped [Tm2oba3(H2O)4]·1.38H2O (3) for which single-crystal X-ray measurements were performed. Isomorphous compounds 1 and 2 consist of eight-coordinated lanthanide ions bonded with oba, Hoba and aqua ligands into the 2D layers. In the structure 3 two types of Tm(III) centers are bridged by oba linkers into 2D layer architecture. Uncoordinated water molecules are located within the cavities between layers. Furthermore, the ATR-IR spectra of isolated monocrystals and thermal behaviours of the compounds are discussed.