Two structurally related flexible bis(imidazole) ligands, N,N′-(1,1-methyl)bis(imidazole) (L 1 ) and N,N′-(1,4-butanediyl)bis(imidazole) (L 2 ) reacted with Ag I , Cu II , Zn II , and Cd II salts under hydrothermal conditions (except for 2 at room temperature), resulted in the formation of eight novel metal-organic coordination architectures, from one-dimensional (1D) chain to three-dimensional (3D) network structures:, and {[Zn(L 2 ) 2 ](ClO 4 ) 2 } n (8). All complexes have been structurally characterized by X-ray diffraction analysis. In 1, the Ag I centers are two-coordinate with linear geometry and L 1 ligands bridge the Ag I centers to form 1D single helical chains. 2 and 7 have 1D double chain structures with the central metal ions being six-coordinated by four discrete L 1 and two apical ligands (water molecules for 2 and N 3for 7). 3 and 4 are isostructural two-dimensional (2D) (4,4) networks with square planar Cu II centers. 5 and 6 also are isostructural with CdSO 4 -like 3D framework structures. In 8, the Zn II ions are tetrahedral, and each L 2 ligand links two Zn II ions to form a 1D double chain.

Six d10metal coordination polymers have been prepared and characterized. Complexes possess structural diversities with interesting topologies and high catalytic activities for the degradation of methyl orange.

{[Cd 3 (btec)(btx) 0.5 (m 3 -OH)(H 2 O)]?H 2 O} n (1) and [Cu 2 (btec)(btx) 1.5 ] n (2), two novel cadmium(II) and copper(II)-based high-connected metal-organic frameworks, with both 1,2,4,5benzenetetracarboxylate (btec) and 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene (btx) as mixed ligands were hydrothermally synthesized and structurally characterized. Both MOFs have three-dimensional (3D) structures, but different framework topologies and ligand linkage modes. 1 possesses an unprecedented binodal (4,12)-connected topology structure, in which the ligand btec serves as a rare dodecadentate and ordinary octadentate in two types of coordination modes. Meanwhile, 2 exhibits a binodal (4,7)-connected topological network with an enneadentate coordination geometry of the btec ligand. Both MOFs provide novel examples of designing and synthesizing novel binodal MOFs, and demonstrate that the 1,2,4,5-benzenetetracarboxylic acid ligand with rich coordination chemistry information is useful in the construction of binodal highly-connected nets. In addition, the catalytic performance of 2 has also been checked. 2 is active as a catalyst for the degradation of methyl orange. Experimental section Materials and general methodsAll the solvents and reagents for synthesis were commercially available and used as received. The ligand btx was synthesized according to a literature method. 8 Elemental analysis of C, H, and N were performed on a Perkin-Elmer 240C analyzer. IR spectra were measured on an FT-IR AVATAR 360 (Nicolet) spectrophotometer with KBr pellets. Powder X-ray diffraction

The hydrothermal reactions of 1,2,4,5-cyclohexanetetracarboxylic acid (HL) with CoCl·2HO and rigid or semi-rigid bis(imidazole) ligands were able to generate two Co(ii) coordination polymers (CPs), {[Co(L)(1,4-bimb)(μ-OH)(HO)]·2HO} (1), {[Co(L)(1,4-bib)]·HO} (2) (1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)benzene, 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene). CPs 1 and 2 were structurally characterized by elemental analysis, IR spectroscopy, X-ray powder diffraction and single crystal X-ray diffraction. CP 1 features a 3D 3,3,4,4,5-connected framework with an unprecedented {4·8·10·12}{4·6·8}{4}{4}{6·8} topology, which represents the first example of CPs with such a topology. CP 2 possesses a three-fold interpenetration 3D framework with mog topology. The distinct structures of the two CPs may result from diverse coordination modes of the (L) ligands and different structural characteristics of rigid or semi-rigid N-donor ligands. The thermal stabilities, photoluminescence properties and electrochemical behavior in the solid state for CPs 1 and 2 have been investigated. The photophysical studies indicated that CPs 1 and 2 are potential semiconductive materials. Moreover, both CPs 1 and 2 show high photocatalytic efficiency for the degradation of methylene blue (MB) under UV light irradiation and exhibit good stability and recyclability. A possible photocatalytic mechanism is speculated by introducing t-butyl alcohol (TBA) as a widely used ˙OH scavenger.

Four metal–organic frameworks (MOFs) were obtained from the hydrothermal reaction of Co(ii) and with dicarboxylic acid and flexible bis(5,6-dimethylbenzimidazole) and characterized. The four MOFs exhibit distinct 2D or 3D structural frameworks.

A cobalt­(II) coordination polymer with an unusual 4,4,4-connected network was hydrothermally synthesized and observed with high thermal, solvent, and pH stabilities. This polymer can serve as the first dual-responsive fluorescent chemosensor for the selective detection of acetylacetone and Cr2O7 2– ion (pH 3.0) in aqueous systems.

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Herein, a nickel coordination polymer (CP 1), {Ni(1,4-bib)(TPA-Cl)·HO} (1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene, HTPA-Cl = 2,5-dichloro-terephthalic acid), has been synthesized under solvothermal conditions. The structure of CP 1 is a 3D 3-fold interpenetrating framework with the sqc12 topology. The thermal stability and luminescence properties of CP 1 were investigated. Scanning electron microscopy (SEM) images of this material display that it possesses an irregular block 3D structure. Interestingly, CP 1 can serve as a multifunctional material via its luminescence sensing, electrochemical sensing, and photocatalytic properties. The experimental results indicate that CP 1 is an efficient luminescent sensor for the detection of Fe ions in an aqueous solution. In addition, CP 1 exhibits a sensitive and rapid electrochemical response to nitrite ions in water solution. The photocatalytic activities of CP 1 were evaluated in the degradation of different dye contaminants (MB, RhB, and MO), and the results demonstrate that its photocatalytic efficiency for the degradation of MB is highest (92.1% for MB, 85.7% for RhB, and 86.2% for MO). The effects of different dyes, different powers of UV light, and different amounts of catalyst CP 1 on the photocatalytic efficiency were also explored. Finally, the mechanism of the luminescence quenching effect toward Fe ions, electroreduction of nitrite ions, and photocatalytic degradation of different dyes have been investigated in detail.