Search

Abstract: Three novel d10 metal coordination polymers, {[Cd(H2odpa)(phen)2]·H2O} n (1), [Cd2(odpa)(phen)(H2O)2] n (2), {[Zn4(odpa)2(phen)2(H2O)2]·H2O} n (3), (H4odpa=4,4′-oxydiphthalic acid, phen=1,10-phenanthroline) were obtained with different metal/ligand ratios through hydrothermal method and characterized. Compound 1 forms a one dimensional zigzag chain, in which two phen ligands chelate to one cadmium atom. Compound 2 shows a three dimensional network structure comprised of new tetranuclear cadmium clusters as the nodes and (odpa)4− anions as the linkers, exhibits an unusual topological structure. Compound 3 is an unprecedented three dimensional polymer based on octanuclear zinc clusters cross-linked by (odpa)4− anions. In 1–3, central CdII/ZnII ions and (odpa)4− ligand display completely different coordination modes and conformations. In addition, the thermal stabilities and photoluminescence properties of 1–3 were also studied. [Copyright &y& Elsevier]

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: To determine the influence of metal ion and the auxiliary ligand on the formation of metal–organic frameworks, six new coordination polymers, {[Mn2(bpdc)(bpy)3(H2O)2]·2ClO4 ·H2O} n (1), {[Mn(bpdc)(dpe)]·CH3OH·2H2O} n (2), {[Cu(bpdc)(H2O)2]} n (3), {[Zn(bpdc)(H2O)2]} n (4), {[Cd(bpdc)(H2O)3]·2H2O} n (5), and {[Co(bpdc)(H2O)3]·0.5dpe·H2O} n (6) (H2bpdc=2,2′-bipyridine-3,3′-dicarboxylic acid, bpy=2,2′-bipyridine, dpe=1,2-di(4-pyridyl) ethylene), have been synthesized and characterized. Compound 1 forms 1D helical chain structure containing two unique MnII ions. In 2, the bridging ligand dpe links Mn-bpdc double zigzag chains to generate a layer possesses rectangular cavities. In 3, bpdc2− ligand connects to three metal centers forming a 2D network. Different from the above compounds, 4 displays a 1D double-wavelike chain. Compound 5 features a helical chain. Compound 6 also displays a helical chain with guest molecule dpe existing in the structure. These diverse structures illustrate rational adjustment of metal ions and the second ligand is a good method for the further design of helical compounds with novel structures and properties. In addition, the magnetic properties of 2, 3 and 6, the thermal stabilities and photoluminescence properties of 4 and 5 were also studied. [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]