Guangzeng Liu

Syntheses, structures, and magnetic properties of six coordination polymers based on 4,5-di(4′-carboxylphenyl)phthalic acid and different bis(imidazole) bridging linkers

Six 4,5-di(4′-carboxylphenyl)phthalic acid (H4DCP) based coordination polymers (CPs), namely {[Ni(1,4-bib)(HDCP)2(H2O)2]0.5[Ni(1,4-bib)(H2O)4]·2H2O}n (1), [Ni(H2DCP)(1,4-bidb)2(H2O)]n (2), [Co2(DCP)(1,3-bib)]n (3), {[Co2(DCP)(1,4-bidb)2]·2H2O}n (4), [Co(H2DCP)(4,4′-bibp)]n (5), and [Co2(DCP)(4,4′-bibp)2]n (6), were synthesized under hydrothermal conditions in the presence of bis(imidazole) bridging linkers (1,3-bib = 1,3-bis(imidazol-1-yl)benzene, 1,4-bib = 1,4-bis(imidazol-1-yl)benzene, 1,4-bidb = 1,4-bis(imidazol-1-yl)-2,5-dimethyl benzene, 4,4′-bibp = 4,4′-bis(imidazol-1-yl)biphenyl). Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Single crystal X-ray diffraction analysis reveals that complex 1 is a cocrystal consisting of two independent chains. Complex 2 exhibits a traditional 2-fold 66-dia parallel entangled network. Complex 3 displays a novel 3D binodal (5,7)-connected net based on binuclear {Co2} units with the Schlafli symbol (3·44·54·6)(32·48·58·63). Complex 4 shows a 2-fold binodal (4,4)-connected bbf net with the point symbol (64·86)(66)2. Complex 5 affords a 2D (44·62)-sql net constructed from {Co2} dinuclear units. Complex 6 displays a novel (3,8)-connected architecture with the Schlafli point symbol (42·5)2(44·510·68·74·82) based on {Co4(COO)6} SBUs. Magnetic studies indicate complexes 3 and 6 exhibit weak ferromagnetic and antiferromagnetic properties, respectively.

Syntheses, topologies, and luminescence of four Ln–organic polymers constructed from aromatic tetracarboxylic acids

Four new coordination polymers (CPs), {[H2N(CH3)2]2[Ln2(BPT)(ox)2]}n (Ln = Er for 1, Yb for 2, and Sm for 3; H2ox = oxalic acid) and {[Gd(HDCP)(H2O)]·H2O}n (4), have been constructed from Ln ions and two aromatic tetracarboxylate acids (H4BPT = 3,3′,5,5′-biphenyltetracarboxylic acid, H4DPT = 4,5-di(4′-carboxylphenyl)phthalic acid) under solvothermal reactions through the linker extension strategy. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Complexes 1–3 are isomorphous and exhibit an unprecedented (6,8)-connected 3D architecture with a point symbol of (33·410·57·62·76)(33·46·56)2, which is built up from right- and left-handed [Ln(ox)]n helixes. Complex 4 shows a 3D (4,8)-connected flu net with (412·612·84)(46)2 topology based on 1D [Gd(COO)2]n ladder chains. Moreover, their luminescence properties have been investigated.

Structural diversity, luminescence and photocatalytic properties of six coordination polymers based on designed bifunctional 2-(imidazol-1-yl)terephthalic acid

Six coordination polymers (CPs), {[M(ITA)]·0.5H2O}n (M = Zn 1, M = Mn 2), {[Zn(ITA)(bib)0.5]·1.5H2O}n (3), {[Ni(ITA)(bib)0.5(H2O)3]·H2O}n (4), {[Zn(ITA)(bimb)0.5]·0.5H2O}n (5) and [Cd(ITA)(bimb)0.5(H2O)2]n (6), have been derived from the designed bifunctional 2-(imidazol-1-yl)terephthalic acid (H2ITA) with or without bis(imidazole) linkers (bib = 1,4-bis(imidazol-1-yl)benzene, bimb = 1,4-bis(imidazol-1-ylmethyl)benzene). X-Ray single-crystal diffraction analysis reveals that complexes 1 and 2 are isomorphic with the same 3D (4)-connected {4·63·82} net. Complex 3 features a 3D 2-fold interpenetrated (3,4)-connected fsc net with point symbol of {4·82·103}{4·82}. Complex 4 displays a 2D 3-connected {63)-hcb sheet, which can be further expanded into a 3D supramolecular network through hydrogen bonding interactions. Complex 5 exhibits an unprecedented 3D 2-fold interpenetrated (3,4)-connected dmc net with point symbol of {4·82}{4·85}. Complex 6 shows a 3D (3,4)-connected {4·82·103}{4·82}-fsc net. Structural comparison reveals that not only the coordination preferences of metal ions but also the auxiliary bis(imidazole) linkers play crucial roles in the control of the final structures. Besides, the photoluminescence properties as well as the photocatalytic activities for the degradation of methylene blue (MB) under UV-vis light of 1, 3, 5 and 6 have been investigated.

Exploratory syntheses, structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse PbII coordination complexes, [Pb3O(OH)(4-sphth)]2(H2O) (1), [Pb(3,5-Hdhb)]H2O (2), and [Pb3(4-nphth)2(OH)2] (3) (4-H3sphth, 4-sulfophthalic acid; 3,5-H2dhb, 3,5-dihydroxybenzoic acid; 4-H2nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb4O4] cubanes, based on which ladder-shaped structure is built via 4-H3sphth bridge. This is the first Pb4O4-containing polymer. The Pb2O2 units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb3O units, which are linked through Pb corners to form a hexagonal unit. Each PbO6 polyhedron is connected to three polyhedra (Pb3O) via sharing an edge (two μ 3-oxygen atoms) and two faces (three μ 3-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.

Synthesis and crystal structures of three new complexes derived from 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole

Three new coordination complexes, [Cd2(ppt)2(cpba)] · (H2O)2 (1), [Zn(ppt)2] · (H2O) (2), and [Zn(MoO4)(Hppt)] (3) (H2cpba: 3-(2′-carboxy-phenoxy)-benzoic acid; Hppt: 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole), were synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. X-ray diffraction analyses revealed that Cd(II) ions are linked by ppt− to form a ladder-shaped structure along the a-axis and further displays a 2-D supramolecular architecture with cpba2− along the c-axis. In 2, each Zn(ppt)2 fragment is linked by the nitrogen of pyridin-3′-yl from the neighboring Zn(ppt)2 forming a V-shaped chain. Compound 3 consists of a ladder structure, in which each {MoO4} unit is a bridge linking three Zn(Hppt)2+ fragments.

Exploratory syntheses and structural characterizations of three organic–inorganic hybrid polyoxomolybdate frameworks linked by M(II)-Ln units (M = Ni, Co, Zn; L = 2,2′-biimidazole)

Three new polyoxomolybdate compounds, {[Ni(H2biim)2(H2O)](Mo3O10)} n (1), [Co(H2biim)2(Hbiim)]2(H2Mo8O26)](H2O)4 (2), and {[Zn(H2biim)2(H2O)][Mo8O28(MoO2(H2biim)2)2](H4biim) (3) (H2biim, 2,2′-biimidazole), were designed and synthesized under hydrothermal conditions. X-ray diffraction analysis reveals that 1 is a snake-shaped chain consisting of asymmetric blocks of {Mo3O10}, in which the ratio of the octahedra {MoO6} and square pyramids {MoO5} is 1 : 2. Compounds 2 and 3 exhibit different structures, although similar synthetic environments (including pH, temperature, and reaction time) were employed. In 2, the cluster of H2Mo8 is decorated by two fragments of Co(H2biim)2(Hbiim)+ via the organic bridge of Hbiim−. Compound 3 consists of one γ-Mo8 , capped by two fragments of {MoO2(H2biim)2)2}2+ via terminal oxygens.