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Abstract: Two novel cadmium(II) coordination polymers [Cd(pyip)(ox)]·H2O (1) and [Cd2(pyip)2(ox)2·(H2O)][Cd(pyip)(ox)]·4(H2O) (2) (pyip=2-(pyridin-3-yl-1H-imidazo [4,5-f][1,10]phenanthroline, H2ox=oxalic acid), have been hydrothermal synthesized and characterized by single crystal X-ray diffraction. Compound 1 is 1D zigzag chain, in which oxalate anion as bridging ligand is responsible for the formation of the main framework and pyip as chelating ligand grafts on two sides of the zigzag chain. Compound 2 contains two kinds of independent polymers [Cd2(pyip)2(ox)2(H2O)] (A) and [Cd(pyip)(ox)] (B) to form an interdigitated 1D+1D structure, in which polymers A and B are paratactically assembled in an ABCD sequence. The fundamental unit of polymer B in 2 is the same as that in 1. For compounds 1–2, weak interactions, primarily hydrogen bonding and π⋯π stacking interactions, have greatly influence on the supramolecular motifs recognized in the crystal packing. Especially, the oxalate anions as bridging ligand simultaneously adopt multiform coordination modes in two compounds. In addition, 1 and 2 displayed a strong fluorescent emission in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Using the principle of crystal engineering, six metal-organic coordination polymers, [Cd(bdc)(3-pytpy)] n ·2nH2O (1), [Cd(bdc)0.5(3-pytpy)] n · n(ClO4) (2), Cd(ndc)0.5(3-pytpy)] n · n(ClO4) (3), [Zn(ndc)(3-pytpy)] n (4), [Cd(bqdc)(3-pytpy)] n (5), and [Zn(pam)(3-pytpy)] n ·2nH2O (6) (H2bdc=benzene-1,4-dicarboxylic acid, H2ndc=naphthalene-2,6-dicarboxylic acid, H2bqdc=2,2′-biquinoline-4,4′-dicarboxylic acid, H2pam=pamoic acid), were synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. Compounds 1–6 crystallize in the presence of organic-acid linkers as well as multi-functional N-donor ligand 4′-(3-pyridyl)-2,2′:6′,2′′-terpyridine (3-pytpy). In complexes 1, 4, 5, and 6, the dicarboxylate as bridging ligand connects metal atoms to form the main body of 1D zigzag chains for 1 and 4, nearly linear chain for 5 and helical chain for 6, while 3-pytpy as tridentate chelating ligand is just like lateral arm grafting on both sides of these chains. In complexes 2 and 3, both the dicarboxylate and 3-pytpy as bridging ligands connect metal atoms into 2D polymeric structure for 2 and 1D chain of alternating loops and rods for 3. The weak interactions such as hydrogen bonding and π···π stacking were investigated on the formation of superamolecular structures and the influence of organic acid on the formation of the final structures was discussed. In addition, the photoluminescent properties of 1–6 were also determined. [Copyright &y& Elsevier]