Hydrothermal syntheses, crystal structures and luminescence of two novel metal-organic frameworks

Two novel metal-organic coordination polymers, [Cd(bqdc)(phen)(2)](n) (1), [Cd(bqdc)(phen)](n) (2), (H(2)bqdc = 2,2'-biquinoline-4,4'-dicarboxylic acid, phen = 1,10-phenanthroline) were obtained with different metal/ligand ratios through hydrothermal method. Their structures were determined by single-crystal X-ray diffraction. In two complexes, central Cd2+ ions and (bqdC)(2-) ligands display completely different coordination modes. 1 is a 1-D zigzag chain, two phen ligands chelate to one Cadmium atom, which is rare in similar polymers. 2 is a 3-D framework, exhibits an unusual eight-coordinate structure (CdN2O6) and the coordination polyhedron can be described as distorted monocapped pentagonal bipyramid. 1 and 2 are stable in air, and show blue photoluminescence at room temperature.