Two Zn(II) and Co(II) compounds with dicarboxylates and curved 4,4′-azopyridine ligands: Syntheses, crystal structures and gas sorption properties

Two new compounds Zn(PDA)(AZPY)center dot 4H(2)O (1) and [Co(NDC)(AZPY)](2)center dot 2H(2)O center dot DMF (2) (H(2)PDA = pyridine2,6-dicarboxylic acid, AZPY = 4,4'-azopyridine, H2NDC = 2,6-naphthalenedicarboxylic acid) were prepared through solvothermal reactions and characterized. Single crystal X-ray diffraction analysis indicates that compound 1 exhibits a one-dimensional chain structure, while compound 2 features a three-dimensional framework. Notably the bridged AZPY ligands involved in both compounds exhibit rare bent configurations. The thermal stability and gas sorption properties of compound 2 have also been studied. A normal amount (2.8 mmol g(-1)) of hydrogen uptake at 1 atm and -196 degrees C for compound 2 were observed, which can be attributed to the presence of micropores. (C) 2012 Elsevier Inc. All rights reserved.