Four coordination polymers, namely, [Zn(HL1)(L2)0.5]·H2O (1), [Cd(HL1)(L2)0.5]·H2O (2), [Zn(L1)(L3)0.5]·H2O (3), and [Cd(L1)(L3)0.5] (4) (H3L1 = (3,5-dicarboxyl-phenyl)-(4-(2′-carboxyl-phenyl)-benzyl)ether, H2L2Cl2 = 1,1′-bis(4-carboxy-benzyl)-4,4′-bipyridinium dichloride, and L3Cl2 = 1,1′-dimethyl-4,4′-bipyridylium dichloride), have been synthesized hydrothermally. The structures of compounds 1–4 have been determined by single-crystal X-ray diffraction analyses, and further characterized by elemental analyses, infrared (IR) spectra, powder X-ray diffraction (PXRD) analyses, and thermogravimetric analyses. Compounds 1 and 2 display three-dimensional 2-fold interpenetrating frameworks, whereas compounds 3 and 4 exhibit two-dimensional layer structures. These compounds display photochromic behaviors from pale yellow to green under UV light, visible light, or sunlight. The photochromic mechanisms of these compounds have been studied by IR spectra, PXRD analyses, UV–vis absorption spectra, electron paramagnetic resonance spectra, density functional theory calculations, and X-ray photoelectron spectroscopy. The capabilities of compounds 1 and 2 as inkless and erasable printing media have also been tested. Moreover, the photomodulated fluorescence of these compounds has also been investigated.

•The two compounds have the same metal to ligand ratio but different metal ions.•The compounds are based on the phosphonic acid and multidentate N-donor ligand.•The effects of the metal ions on the final structures have been discussed.•The optical band gaps of the two compounds have been investigated.•The photoluminescent and photocatalytic properties of the compounds have been studied.Two new coordination polymers [Cd(4,4′-tmbpt)(HL)(H2O)] (1) and [Cu(4,4′-tmbpt)(HL)]·H2O (2) (H3L = 2′-carboxybiphenyl-4-ylmethylphosphonic and 4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole) have been synthesized hydrothermally. The two compounds have the same metal to ligand ratio, but different metal ions. As a result, the two compounds display different 2D layer structures, which is mainly caused by the different coordination numbers of the different metal ions. The effects of the metal ions on the structures, the optical band gaps and photoluminescent and photocatalytic properties of the compounds have been studied.Two new coordination polymers based on 2′-carboxybiphenyl-4-ylmethylphosphonic and the multidentate N-donor ligand 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole have been synthesized with different metal ions under hydrothermal conditions. The effects of the metal ions on the structures of the compounds have been discussed. Moreover, the optical band gaps, photoluminescent and photocatalytic properties of the compounds have been studied.

Hydrothermal reactions of 2′-carboxybiphenyl-4-ylmethylphosphonic acid (H3L) with Cd(CH3COO)2·2H2O and 1,10-phenanthroline (phen) under different reaction temperatures afforded three new compounds, namely [Cd(phen)(HL)]·H2O (1), [Cd3(phen)4(L)2(H2O)]·9H2O (2) and [Cd4(phen)5(HL)(L)2]·2.5H2O (3). Compounds 1–3 have the same component but different structures. Compound 1 synthesized at 100 °C displays a one-dimensional chain structure containing mononuclear Cd. Compounds 2 and 3 formed at 160 °C exhibit one-dimensional chain structure containing trinuclear Cd unit and zero-dimensional structure containing hexanuclear Cd unit, respectively. The compounds have been characterized by elemental analyses, infrared spectra (IR), UV–vis spectra, single-crystal X-ray diffraction analyses and thermogravimetric analyses. The optical band gaps and photoluminescent properties of compounds 2 and 3 have been investigated.

Hydrothermal reaction of the multidentate N-donor ligand 1-((1H-1,2,4-triazol-1-yl)methyl)-3-(4-pyridyl)-5-(2-pyridyl)-1,2,4-triazole (2,4′-tmbpt), 5-hydroxy-1,3-benzenedicarboxylic acid (5-OH-H2bdc), and Cd(CH3COO)2·2H2O in the presence of NaOH afforded a coordination polymer [Cd(2,4′-tmbpt)2(5-OH-bdc)]·5H2O (1), which exhibits a 1D → 2D → 3D supramolecular architecture. The photoluminescent spectra of the compound in different aqueous solutions in the pH range of 1–14 have been investigated. The results indicate that compound 1 can be used as an efficient pH fluorescent sensor and molecular logic gate. The pH sensing mechanism of the compound has been discussed and proved by the UV–Vis spectra.A novel 1D → 2D → 3D supramolecular coordination polymer has been synthesized hydrothermally. This compound can be used as an efficient pH fluorescent sensor and molecular logic gate.Download high-res image (205KB)Download full-size image

•Compounds 1 and 2 are constructed from octamolybdate and NH2-containing ligand.•The compounds are characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR, PXRD and TGA.•Compounds 1 and 2 have small band gaps.•Compounds 1 and 2 have high photocatalytic activities for degradation of MB under visible light irradiation.Two coordination polymers based on octamolybdate and 2-aminopyrazine, namely, [CuI2(HL)2(L)(β-[Mo8O26])]·3H2O (1) and [(H2L)2(β-[Mo8O26])]·4H2O (2) (L = 2-aminopyrazine), have been synthesized hydrothermally. The structures of the compounds were determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra, elemental analyses, powder X-ray diffraction analyses and thermogravimetric analyses. Compound 1 displays a double chain structure, which is extended by the intermolecular NH ⋯ O hydrogen-bonding interactions to generate a 3D supramolecular architecture. Compound 2 exhibits a discrete structure, which is connected by the intermolecular OH ⋯ O hydrogen-bonding interactions to yield a 3D supramolecular architecture. Compounds 1 and 2 display small band gaps of 1.89 and 1.66 eV, respectively. Moreover, compounds 1 and 2 exhibit high photocatalytic activities for degradation of methylene blue under visible light irradiation.Two coordination polymers based on octamolybdate and 2-aminopyrazine have been constructed under hydrothermal conditions. These compounds display small band gaps and high photocatalytic activities for degradation of methylene blue under visible light irradiation.Download high-res image (190KB)Download full-size image

•A dual functional fluorescent coordination polymer for sensing of nitrobenzene and Cr2O72− anion has been obtained.•The sensing mechanism has been confirmed theoretically and experimentally.•The optical band gap and temperature variable luminescence of the compound have been studied.A one-dimensional coordination polymer, namely [Cd(bipy)][HL]n (1) (H3L = 2′-carboxybiphenyl-4-ylmethylphosphonic acid, and bipy = 2,2′-bipyridine) has been synthesized under the hydrothermal condition. The structure of the compound has been determined by single crystal X-ray diffraction analysis, and further characterized by elemental analysis, infrared spectrum, thermogravimetric analysis, and UV–vis absorption spectrum. This compound can be used as an excellent dual functional fluorescent sensor for the selective and sensitive detection of the hazardous environmental contaminants nitrobenzene and dichromate (Cr2O72−) anion. Compound 1 represents a rare example of dual functional fluorescent sensor, which can detect nitrobenzene and Cr2O72− simultaneously. The sensing mechanism of the compound has been confirmed theoretically and experimentally. Moreover, the optical band gap and temperature variable photoluminescence of the compound have been investigated.A one-dimensional coordination polymer has been synthesized hydrothermally. This compound can be used as an excellent dual functional fluorescent sensor for the selective and sensitive detection of the environmental contaminants nitrobenzene and dichromate anion. Moreover, the sensing mechanism, optical band gap and temperature variable photoluminescence of the compound have been investigated.Download high-res image (377KB)Download full-size image

•Compound 1 displays a highly connected structure.•The N-donor ligand is multidentate.•The photoluminescent property of the compound has been studied.•The optical band gap of the compound has been studied.A novel coordination polymer based on the multidentate N-donor ligand 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole (3,3′-tmbpt) and 1,2,4,5-benzenetetracarboxylate anion (btec), namely, [Zn5(3,3′-tmbpt)(btec)2(OH)2] (1), has been synthesized hydrothermally. Compound 1 displays a rare 3D (3,4,11)-connected framework based on a [Zn5(OH)2]8 + cluster. The optical band gap and photoluminescent property of compound 1 have been studied.A novel coordination polymer with (3,4,11)-connected structure has been prepared under hydrothermal condition, where its photoluminescent property and optical band gap have also been studied.

A series of coordination polymers constructed from tripodal N-donor ligands and polycarboxylate anions, namely, [Ag6(3,4′-tmbpt)(btc)2]·2H2O (1), [Ag2(3,4′-tmbpt)(H2btec)]·H2O (2), [Ag2(4,4′-tmbpt)(Hbtc)]·H2O (3), [Cd3(4,4′-tmbpt)(btc)2(H2O)6]·7H2O (4), [Co(4,4′-tmbpt)(btec)0.5(H2O)] (5) and [Ni(4,4′-tmbpt)(btec)0.5(H2O)] (6), where 3,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazole, 4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole, H3btc = 1,3,5-benzenetricarboxylic acid, and H4btec = 1,2,4,5-benzenetetracarboxylic acid, have been hydrothermally prepared. Single crystal X-ray diffraction analyses indicate that compound 1 exhibits a 3D (3,4,6)-connected framework with (4·62)2(6·85)2(4·62·83·12) topology. Compound 2 has a 3D (3,4)-connected framework with (63)2(42·64)(42·63·8) topology. Compound 3 exhibits a 2D layer structure. Compound 4 shows a 3D 2-fold interpenetrating framework with (6·102) topology. Compounds 5 and 6 exhibit similar 2D → 3D polythreading architectures. These compounds have been characterized by infrared spectra (IR), elemental analyses and powder X-ray diffraction (PXRD) analyses. The effects of the organic anions on the structures of the compounds have been discussed. Moreover, the photoluminescent properties of the compounds have been investigated.Six coordination polymers based on multidentate N-donor ligands and different aromatic polycarboxylate anions have been prepared and characterized, where the effects of the organic anions on the structures have been discussed. Moreover, the photoluminescent properties have also been studied.

•Compounds 1 and 2 display highly connected structures.•Compound 3 shows a polythreading architecture.•The N-donor ligand is multidentate.•The photoluminescent properties of the compounds have been studied.Three coordination polymers based on multidentate N-donor ligands and polycarboxylate anions, namely, [Co3(4,4′-tmbpt)4(btc)2]·9.5H2O (1), [Ag4(4,4′-tmbpt)(btec)(H2O)2]·H2O (2) and [Zn(4,4′-tmbpt)(btec)0.5(H2O)]·0.5H2O (3) (4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole, H3btc = 1,3,5-benzenetricarboxylic acid, and H4btec = 1,2,4,5-benzenetetracarboxylic acid) have been prepared under hydrothermal condition. Compound 1 displays a 3D (3,6,8)-connected framework with (4·62)(44·610·8)(414·612·82) topology. Compound 2 is a 3D (4,5,8)-connected framework with (43·62·8)(43·65·82)(48·62)(410·610·88) topology. Compound 3 exhibits a 2D → 3D polythreading architecture. The photoluminescent spectra indicate that at room temperature, compounds 2 and 3 emit green and blue luminescence, respectively.Two coordination polymers with highly connected structures and one with polythreading architecture have been prepared under hydrothermal conditions, where their photoluminescent properties have also been studied.

Two coordination polymers [Cu(phen)(L)0.5(H2O)] (1) and [Ni2(phen)2(L)(H2O)0.5]·0.5H2O (2), where phen = 1,10-phenanthroline and H4L = 5,5′-(ethane-1,2-diyl)-bis(oxy)diisophthalic acid, have been synthesized under hydrothermal conditions. In complex 1, the L anions and the phen ligands connect the Cu(II) ions to form a layer. The phen ligands act as arms and thread into the adjacent layer, forming a 2D → 3D polythreaded architecture. In complex 2, the L anions and the phen ligands link the Ni(II) ions to form a layer. Further, the adjacent layers interdigitate each other through intermolecular π − π interactions to generate a 2D → 3D interdigitated architecture. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR) and elemental analyses. The thermal properties and optical band gaps of complexes 1 and 2 have also been investigated.