Syntheses and characterizations of four metal coordination polymers constructed by the pyridine-3,5-dicarboxylate ligand

Abstract: A series of metal-organic frameworks, namely [Ni(PDB)(H2O)] n (1), [Pb(PDB)(H2O)]·(H2O) (2), [Co2(PDB)2(bpy)2(H2O)4]·4H2O (3) and [Co2(PDB)2(phen)2] n (4) (H2PDB=pyridine-3,5-dicarboxylic acid, bpy=2,2′-bipyridine, phen=1,10-phenanthroline), have been synthesized based on pyridine-3,5-dicarboxylate acid and two neutral chelate ligands, with different metal ions such as NiII, CoII and PbII, under hydrothermal conditions. The framework structures of these polymeric complexes have been determined by the X-ray single crystal diffraction technique. In the four complexes, the pyridine-3,5-dicarboxylate acid ligand exhibits diverse coordination modes, which play an important role in the construction of metal-organic frameworks. The thermal analyses of these four complexes have been measured and discussed. In addition, complex 2 shows strong phosphorescent emission at room temperature and the magnetic measurement of the polymer of 4 reveals a typical antiferromagnetic exchange. [Copyright &y& Elsevier]