Search

Four coordination polymers (CPs) based on H 2 tbta ligand, namely, [Zn(tbta) (bmbp)] n (1), {[Cd 0.5 (tbta) (H 2 O)] n ·(Hbia) (H 2 O)} (2), [Cu 1.5 (tbta) (OH) (bi) (H 2 O)] n (3) and [Cd(tbta) (ei) 2 ] n (4) have been synthesized and characterized (H 2 tbta = 2,3,5,6-tetrabromoterephthalic acid, bmbp = 4,4'-dimethyl-2,2'-bipyridine, bia = 1H-benzo[d]imidazol-2-amine, bi = 1H-benzo[d]imidazole, ei = 2-ethyl-1H-imidazole). Single-crystal X-ray diffraction analyses illustrate 1 and 4 exhibit 1D chains, and compound 1 and 4 are hydrogen-bonded into a 2D layer to form a 3D supramolecular structure. Compounds 2 and 3 show 2D layered structures and further expand to 3D supramolecular structures through hydrogen bonds. Structural comparisons indicate that the position of coordination sites and substituent groups plays a crucial role in the control of the final structures. Besides, the photoluminescence properties of compounds 1 , 2 , 4 and UV–vis spectra of 3 have been investigated in the solid state at room temperature. Image 1 • Four CPs based on H 2 tbta ligand were synthesized and structurally characterized. • The auxiliary ligands drastically affect the formation of low-dimensional structures. • The UV–vis spectrum and luminescence properties were studied. [ABSTRACT FROM AUTHOR]

Three novel metal-organic complexes, formulated as [Cu 2 (2-HBA) 2 (bimb) 4 ] (1), {[Cd(CEDA)(bimb)]·H 2 O} n (2), and {[Ag 2 (bimb) 2 ]·(1,4-CDA)·13H 2 O} (3) (bimb = 1,2-bis((1 H -imidazole-1-yl)methyl)benzene; 2-HBA = 2-hydroxybenzoic acid; CEDA = cyclohex-4-ene-1,2-dicarboxylic acid; 1,4-CDA = cyclohexane-1,4-dicarboxylic acid), were synthesized by self-assembly of mixed ligands with Cu(II), Cd(II), and Ag(I) under hydrothermal conditions and characterized by means of single-crystal X-ray diffraction, X-ray powder diffraction, infrared spectra, thermogravimetric analysis, fluorescence spectra and UV–vis absorption spectra. 1 is shown as a 0D structure, which is formed by Cu2+, 2-HBA ligands and bimb ligands. 2 displays a 1D ladder structure, which is built by Cd2+, CEDA ligands and bimb ligands, and it is assembled into 2D structure by hydrogen bonding. 3 possesses a 0D [Ag(bimb)] 2 dimer which is assembled into 3D structure by the Ag O weak interaction and hydrogen bonding. Interestingly, a rare 13-core water cluster participates in forming the network of 3. The UV–vis spectrum and luminescence properties were also studied and discussed. Image 1 • Three novel metal-organic complexes were hydrothermal synthesized. • A rare 13-core water cluster participates in forming the network of compound 3. • The three diverse structures are mainly attributed to the weak interactions. • The UV–vis spectrum and luminescence properties were studied. [ABSTRACT FROM AUTHOR]

Semi-rigid 6-(carboxymethoxy)-2-naphthoic acid (H 2 CNA) was successfully synthesized as a ligand containing O-bridging atom. Six coordination polymers based on H 2 CNA ligand and transition metal ions were successfully synthesized under the hydrothermal or solvothermal conditions, which named [Zn(CNA)] n (1), [Cd(CNA) (H 2 O)] n (2), [Co(HCNA) 2 (H 2 O) 4 ] (3), [Ni(HCNA) 2 (H 2 O) 4 ] (4), [Cu(CNA) (H 2 O)] n (5), [Ni(CNA) (H 2 O)] n (6). Single crystal structural analysis revealed that 1 , 2 , 5 and 6 are shown as 2D structures, and 3 – 4 displays 0D structures. All the structures assembled into 3D supramolecular networks by hydrogen bonding interaction. The thermal stability, luminescent properties and UV–vis spectra of these coordination polymers were discussed in detail. In addition, 5 has good adsorption ability for Congo Red with good selectivity. We synthesized and characterized six CPs based on semi-rigid 6-(carboxymethoxy)-2-naphthoic acid. Image 1 • Semi-rigid 6-(carboxymethoxy)-2-naphthoic acid (H 2 CNA) ligand was synthesized. • Six coordination polymers based on H 2 CNA ligand were synthesized. • Compound 5 has good adsorption ability for Congo Red with good selectivity. [ABSTRACT FROM AUTHOR]

Four coordination polymers, namely, [Zn (DBT) (4,4′-dmbpy) (H 2 O)] n (1), [Co(DBT) (2,2′-bpy) (H 2 O)] n (2), [Zn (DBT) (2,2′-bpy)] n (3), [Zn (DBT) 0.5 (2,2′-bpy) 2 ·(HDBT−)] n (4) (H 2 DBT ​= ​2,5-dibromoterephthalic acid, 4,4′-dmbpy ​= ​4,4′-dimethyl-2,2′-bipyridyl and 2,2′-bpy ​= ​2,2′-bipyridyl) have been synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, IR and thermogravimetric (TG) analysis. These four compounds remained stable until 150 ​°C, and the major quality loss (83–90%) occurred between 150 and 700 ​°C. In mixed ligands system, the main ligand H 2 DBT exhibits monodentate or bidentate bridging coordination modes and the auxiliary ligands 4,4′-dmbpy and 2,2′-bpy both possess bidentate chelate coordination modes. An objective of this study was to investigate the pivotal role of chelating ligands in the formation of low dimensional structures. As the bipyridyl ligands occupy the coordination site, compounds 1 – 3 all display two dimensional structures and 4 shows 1D chains, of which compounds 1 and 2 are isomorphic. The hydrogen bonds and π-π stacking work together in the formation of 3D supramolecular structure of these four compounds. Besides, we investigated their photoluminescence properties in the solid state at room temperature. The compounds 1 , 3 and 4 exhibited good fluorescence performance, and their strong emission peaks were located at 447 ​nm (λex ​= ​285 ​nm) for 1 , 427 ​nm (λex ​= ​330 ​nm) for 3 , and 412 ​nm (λex ​= ​310 ​nm) for 4. Image 1 • Four CPs based on H 2 DBT ligand were synthesized and structurally characterized. • Low-dimensional crystals were obtained by changing experimental conditions. • The luminescence properties were studied. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks {[Ni 0.5 (DTA) 0.5 (H 2 O)]‧H 2 O} n (1) and [Ni(DTA)] n (2), where H 2 DTA = 2,5-di(1H-imidazol-1-yl)terephthalic acid, were constructed from the same reaction system at 120 °C and 180 °C, respectively. Different reaction temperatures were found to trigger different assembly processes and final structures. Single-crystal X-ray analyses show that compound 1 exhibits a 2D layered structure, further forming a 3D supramolecular by hydrogen bonding, while compound 2 shows 2-fold interpenetrating 3D framework with PtS topology. Compounds 1 – 2 have been evaluated as electrode materials for supercapacitors. The results show that compound 1 exhibits better electrochemical performance than 2. It may be ascribed to 2D layered structures facilitating electron transport and sufficient interlayer spaces available for the storage. Image 1 • Two Ni-based MOFs were synthesized and structurally characterized. • Different reaction temperatures were found to trigger diverse assembly processes. • Ni-DTA-2D exhibits better superior electrochemical performance. [ABSTRACT FROM AUTHOR]