Cadmium(II) and zinc(II) coordination polymers built with an ethynyl backbone containing an unsymmterical amide ligand: Syntheses, crystal structures, and photoluminescent properties

Two new crystalline coordination polymers have been synthesized with Zn2+ and Cd2+ ions using an N-(4-(pyridinyl-4-ethynyl)phenyl)-isonicotinamide (HL) donor ligand. The ligand readily reacts with metal nitrate in DMF to afford 1-dimensional (1D) coordination polymers 1 and 2 comprising a repeating unit of [Zn(HL)(NO3)2(DMF)]·DMF and [Cd(HL)(NO3)2(DMF)]·DMF, respectively. Both complexes 1 and 2 were characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), and X-ray diffraction. Both complexes contained a 1D chain in which crystallography revealed two metal ions were connected by each ligand. The weak π–π stacking interactions and intermolecular hydrogen bonds resulted in the one-dimensional network structures. The photoluminescent properties for both complexes were also investigated.