Two d10 Coordination Polymers Based on the Substitutional Aromatic Multicarboxylate and N-donor Co-ligands: Syntheses, Structures and Luminescent Properties

Two new coordination polymers, formulated as Zn(3-NPA)(1,4-bimb) (1) and Cd(3-NPA)(1,2-bimb)(H2O) (2) (3-NPAH2 = 3-nitrophthalic acid, 1,4-bimb = 1,4-bis(imidazol-1 -ylmethyl)benzene, 1,2-bimb = 1,2-bis(imidazol-1-ylmethyl)-benzene) have been synthesized by hydrothermal reactions of the semirigid neutral ligand 1,4-bimb or 1,2-bimb with metal ions in the presence of 3-nitro phthalic acid. The two compounds were characterized by infrared spectroscopy, elemental analysis, thermo gravimetric analysis and single-crystal X-ray diffraction analysis. Polymer 1 possesses a new two-dimensional puckered rectangular grid architecture, with the 1,4-bimb ligands displaying a cis-conformation. In polymer 2, the 3-NPA2− anions coordinate the Cd(II) ions in a tetra dentate mode to form a dimer unit, which is connected by the 1,2-bimb ligands resulting in a single layer. Intra layer hydrogen bond interactions are found between the water molecule and carboxylate oxygen atoms. Weak π···π interactions are observed between the layers through the benzene rings from the adjacent 3-NPA2− and 1,2-bimb ligands. In addition, the luminescent properties of the two compounds were also investigated in this paper.