Self-assembly of two 3D microporous coordination polymers based on 2-oxynicotinate and oxalate ligands

Two new 4f coordination polymers, [Ln3·(onic)2·(ox)4·(H2O)2]·4H2O(Ln=Yb(1), Tm (2), onic=2-oxynicotinate, ox=oxalate) have been synthesized and characterized by element analysis, IR spectroscopy and thermal analysis, as well as single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic system, space group C2/c, which exhibit the network topology with schläfli symbol of (4.64.4)2(42.62.82) constructed from Ln2(ox) units and onic ligands. Moreover, the two complexes represent the 3D microporous coordination frameworks with 25.7% and 24.1% voids occupied by guest water molecules, respectively.