Syntheses, Structures, and Characterizations of a Series of Polymers Constructed by Two V-Shape Dipyridine-Containing Ligands

Two flexible V-shape ligands, namely, 1,3-bis(pyridine-4-ylmethoxy)benzene (4-bpmb) and 1,3-bis(pyridine-2-ylmethoxy)benzene (2-bpmb), have been synthesized and employed for constructing eight novel coordination polymers, {[Zn(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (1), {[Cd(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (2), {[Hg(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (3), {[Zn4(2-bpmb)4Cl8]·C5H5N}n (4), {[Hg(2-bpmb)Cl2]·2H2O}n (5), [Cu4(μ-CH3COO)8(2-bpmb)2]n (6), [Ag(2-bpmb)(NO3)]n (7), {[Cu(2-bpmb)(H2O)2]·(NO3)2}n (8). These complexes were characterized by elemental analyses and IR spectra and structurally determined by powder and single crystal X-ray diffraction analyses. The photoluminescence properties of complexes 1−3 are studied. The results revealed that the 4-bpmb ligands react with II B group transitional metallic nitrates to give three isostructural 1D wavelike chains (complexes 1−3), which are further decorated by equimolar 4-bpmb molecules to form the wavelike double-stranded chain structures via hydrogen bonds. In the packing model of complex 3, a 2D layer network is observed considering the interaction between mercury atoms and nitrate anions from the adjacent chains. The 2-bpmb ligands reacting with the corresponding transition metal salts generate three 1D helical chains, as expected (complexes 4−6). Complex 7 has a 2D layer structure produced by nitrate anions bridging with 1D opposite homohanded helical chains. Complex 8 displays a straight chain due to the coordination of two O atoms of each 2-bpmb ligand with copper cations.