Synthesis, Characterization of an Unusual Crystalline Material with Hydroxycarboxylate Ligand

A new porous coordination polymer with the general formula [Zn(Hmal)(H2O)2]n·nH2O (1) (H3mal = malic acid) has been designed and synthesized via solvothermal routine. In the polymer, the malate dianion acts as the unique quinquedentate ligand with five oxygen atoms participating in the coordination. The Zn(II) ions are interconnected via hydroxyl and carboxyl groups from the malate ligands to form a big loop. Further, the loops were linked by the bidentate β-carboxyl group to shape 2-D porous framework, which exhibits a classical brick-like topology.