Two-dimensional lanthanide(III) coordination polymers. Solvothermal synthesis, crystal structure, and stability

Based on 2-(4-pyridyl)-terephthalate (H${}_2$pta) and oxalate ligands, two new lanthanide-containing coordination polymers (CPs), [Tb(pta)(C${}_2$O${}_4$)${}_{0.5}$(H${}_2$O)${}_2$)]·2H${}_2$O (1) and [Sm(pta)(C${}_2$O${}_4$)${}_{0.5}$(H${}_2$O)${}_2$)]·2H${}_2$O (2), have been synthesized under solvothermal conditions. The structures of both 1 and 2 have been determined by single-crystal X-ray diffraction. Infrared, elemental analysis, powder X-ray diffraction and thermogravimetric analysis data are also presented. The crystals of 1 and 2 exhibit isostructural layer-like networks, crystallizing in the triclinic space group P$\overline{1}$. The layers are further stabilized and associated into 3D architectures through hydrogen bonding. Remarkably, the CPs 1 and 2 exhibit excellent water stability and remarkable thermostability with thermal decomposition temperatures of more than 420 °C.