Hydrothermal synthesis and structural characterization of Zn(II)- and Cd(II)-pyridine-2,3-dicarboxylate 2D coordination polymers, {(NH4)2[M(μ-pydc)2]·2H2O}n

In this study, two novel coordination polymers {(NH4)2[M(μ-pydc)2]·2H2O}n (M = Zn(II), 1 and Cd(II), 2) (H2pydc = Pyridine-2,3-dicarboxylic acid or quinolinic acid) have been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. It has been observed that 1 and 2 have crystallized in the monoclinic space group P21/n. The M(II) ions are coordinated by the tridentate pydc bridging ligand through the oxygen atom of the carboxylate groups and the nitrogen atom of the pyridine ring in a bidentate manner and the oxygen atoms of carboxylate groups of other pydc ligands forming a distorted octahedral geometry. X-ray single crystal structural analyses put forth that two-dimensional frameworks were formed, and were assembled into a three-dimensional supramolecular structure by intermolecular N–H⋯O and O–H⋯O hydrogen bonding interactions.

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► In this study we investigated the coordination chemistry of pyridine-2,3-dicarboxylic acid.
► Two novel coordination polymers have been hydrothermally synthesized.
► In both complexes, the pyridine-2,3-dicarboxylate acts as a tridentate bridging ligands.