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The fatigue cracks of rib-to-deck welded joints in an orthotropic steel deck are one of the critical conundrums that restrict the sustainable development of steel bridges. Double-sided welded joints were achieved by introducing internal welding technology to overcome the initial “crack-like” manufacturing defects at the welding roots of single-sided welded joints. Through the observation of the macro-section of the welded joint, the differences between single-sided welding, partial-penetration welding, and full-penetration welding in rib-to-deck welded joints are compared. Relying on the Shenzhen–Zhongshan link, the fatigue failure and mechanism of single-sided rib-to-deck welded joints are clarified by the nominal stress and structural stress methods, and those of double-sided welded joints were determined through fatigue tests. The fatigue strength of rib-to-deck welded joints is higher than the FAT90 of Chinese standard and the FAT C joints of American standard. The fatigue strength of double-sided rib-to-deck welded joints is significantly higher than that of single-sided welded joints. The fatigue strength of rib-to-deck welded joints is within a ± 2σ range of main S-N curves by the structural stress method. It is suggested to adopt the double-sided welded joints in practice, and to ensure that the penetration rate is beyond 80%. The trial data are limited, and further tests are needed to confirm the results.

The pollution of the water environment affected by organic dyes has been become an increasingly serious and concerning environmental problem. Metal–organic frameworks (MOFs), as an excellent adsorb...

Two novel 3D fluorescent metal-organic frameworks (MOFs), [Cd(L)(bbibp)]n (1) and [Cd(L)(bbibp)0.5]n (2), where H2L = 4,4'-(4,4'-bipyridine-2,6-diyl)dibenzoic acid and bbibp = 4,4'-bis(benzoimidaz-1-yl)biphenyl, were acquired through a conventional method and characterized via IR spectra, single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction (PXRD), scanning electron microscopy, N2 adsorption-desorption isotherms, and X-ray photoelectron spectroscopy (XPS). The crystal framework of Cd-MOF 1 remained stable in the range of pH = 1.0-12.0. Interestingly, the emission peak of 1 showed a red shift and exhibited a fluorescence turn-on effect in an acidic environment. X-ray diffraction measurement revealed that the crystal structure of 1 remained unchanged after immersion in a pH = 1.0 solution. In addition, Cd-MOFs 1 and 2 displayed fluorescent quenching to l-glutamic acid with high sensitivity and selectivity. Meanwhile, 1 showed high selectivity in recognizing Fe3+ under acidic conditions, which made 1 capable of detecting Fe3+ in acidic industrial wastewater. Finally, the fluorescent sensing mechanism was carefully studied by PXRD, transient fluorescence lifetime, XPS, and UV spectroscopy.

Recently, lots of organic dye adsorbents were introduced; the pollution of water bodies caused by adsorbents was an urgent problem to be solved. The modified metal–organic frameworks with magnetic properties provided a great platform for solving this disadvantage. In this study, a novel magnetic material Fe3O4@PmPD–[Co-BT] (Co-BT = [Co(bcpo)0.5(tib)(H2O)2]n, bcpo = 2,5-bis(4-carboxylphenyl)-1,3,4-oxadiazole, tib = 1,3,5-tris(1-imidazolyl)benzene)) was prepared using Fe3O4 modified by mPDs (mPD = m-phenylenediamine). This material was successfully characterized by transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD), and it was confirmed that Co-BT was adhered to the Fe3O4 surface by PmPDs. The dye adsorption performance of magnetic Fe3O4@PmPD–[Co-BT] was investigated in detail with selectivity, capacity, thermodynamics and kinetics studies, and with respect to influence factors including the pH value, solvent types, and ionic strength. Notably, the saturated adsorption capacity of magnetic Fe3O4@PmPD–[Co-BT] for CR dyes could reach 347.8 mg g−1. The dye removal mechanism was investigated by zeta potential analyses and Fourier transform infrared (FTIR) spectroscopy.

Mg batteries are attractive for low-cost and sustainable energy storage because Mg as an anode material is highly abundant in the crust of the Earth, it has a high charge capacity (2205 Ah kg−1 or 3832 A h L−1) benefiting from its two electron redox chemistry, and it undergoes less dendritic growth than other metals (Li and Na). However, the development of Mg batteries is still hampered by the lack of easy-to-make, chemically stable Mg electrolytes. In the current work, we conveniently prepared an ionic liquid Mg electrolyte (MMAC-IL) by mixing MgCl2, AlCl3, Mg, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) together and using them in a one-pot reaction; the product of this reaction did not need to be purified. The MMAC-IL electrolyte exhibited superior anodic and cathodic electrochemical performances, according to electrochemical and spectroscopic studies. Specifically, MMAC-IL delivered robust Mg deposition/stripping cycling for 300 h with minimum polarization change in Mg/Mg half-cell studies. Moreover, the MMAC-IL electrolyte with its high ionic strength significantly suppressed the shuttle effect of magnesium polysulfides and enabled a stable Mg–S battery.

A novel metal organic framework, namely, {[Zn3(btc)2(bimmb)2.5]·2H2O·CH3CN}n (1) (btc = 1,3,5-benzenetricarboxylic acid), bimmb = 1,4-bis(imidazol-l-ylmethyl) benzene), has been reasonably designed...

Two new coordination polymers (CPs) based on transition metals, namely [Ni2(4,4′-cpmb)2(4,4′-bbibp)2(H2O)4]n (1) and [Co(4,4′-Hcpmb)(1,3-bib)]n (2) (flexible 4,4′-H2cpmb = 4-(4-carboxylphenylmethylthio)benzoic acid, rigid 4,4′-bbibp = 4,4′-bis(benzoimidazo-1-ly)biphenyl and 1,3-Hbib = 1,3-bis(1-imidazo-1-ly)benzoic acid), have been designed and successfully synthesized under solvothermal conditions, which have been characterized by elemental analysis, infrared spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that 1 features a 3D supermolecular structure in ABAB mode by H bonds (O⋯H⋯O) with a 2-fold interpenetrating sql topology framework and 2 displays a 3D supermolecular framework by H bonds (O⋯H⋯O) with a rarely fes topology. Moreover, the photo-degradation and dye adsorption properties of CPs 1–2 have been investigated. Importantly, 2 shows good photo-degradation and dye adsorption properties.

Two different novel coordination polymers were synthesized under hydrothermal conditions, namely {[Ni(bibp)3(H2O)2]·2NO3·0.5H2O}n (1), [NiL(bibp)]n (2) (H2L = 3,3′-azodibenzoic acid, bibp = 4,4′-bis(imidazolyl)biphenyl). Complex 2 is based on the introduction of carboxylic acid ligands on complex 1. These two polymers were characterized by single crystal X-ray diffraction, IR spectra, elemental analysis, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Single crystal X-ray diffraction analysis showed that complex 1 formed a 3D structure by weak force. Complex 2 possesses a uninodal 4-connected 3D (three-dimensional) sql topology framework with the point symbol (44·62). In addition, the photocatalytic degradation properties of the two complexes are investigated. Significantly, complex 1 is a good photocatalyst for the degradation of organic dyes (RhB/MO), complex 2 is a good photocatalyst for the degradation of organic dyes (MB). And the possible photodegradation mechanism was proposed and explored.

One novel metal–organic frameworks (MOFs) constructed by one angular ligand and 5-aminoisophthalic acid, namely {[Ni(L)(bpt)(H2O)]·2H2O}n (H2L = 5-aminoisophthalic acid, bpt = 2,5-bis(4-pyridyl)-1,3,4-thiadiazole) has been designed and successfully synthesized under solvothermal condition. This compound was characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction analysis reveals that the compound possesses a uninodal 3-connected 3D (three-dimensional) hcb topology framework with the point symbol (63). The thermal stabilities and electrochemical behavior in the solid state of the compound have been investigated in detail. Moreover, the photocatalytic degradation of the compound has been investigated. The results show photocatalytic activity of the compound for three dyes is MB > MV > RhB.

Two metal-organic frameworks (MOFs) {[Zn(L1)]·2DMA·H2O}n (1) and {[Zn(L2)]·2DMA·H2O}n (2) (H4L1/H4L2 = 5,5’-(1,4/3-xylylenediamino) diisophthalic acid) were synthesized under solvothermal conditions and structurally characterized. Both of the crystals are isomorphs and featuring the dia topological 3D interpenetrated framework, and constructed with Zn(II) cations and two isometric aromatic tetracarboxylate ligands, respectively. The optical adsorption and diffuse-reflection spectrum show that the two crystals could be the potential UV photocatalytic materials, and photocatalytic studies exhibit great degradation activity of three organic dyes (methylene blue (MB), Rhodamine B (RhB) and Methyl orange (MO)).

Six functional metal-organic frameworks build by 4,4'-(1H-1,2,4-triazol-1-yl)methylenebis (benzonic acid) (H2tmlb), namely: [Zn4(tmlb)4(H2O)]n (1), [Ni4(tmlb)4(H2O)]n (2), [Cu(tmlb)]n (3), [Co(tmlb)]n (4), [Pb(tmlb)(H2O)]n (5), {[Zn(tmlb)(H2tmlb)]H2O}n (6), have been successfully synthesized. The X-ray diffraction analysis show that the complexes 1 and 2 exhibited a two interpenetrating (3, 6, 6)-connected framework with a Schlafli symbol of (4·62)2 (42·610·83) topology. The complexes 3 and 4 show a two interpenetrating (3, 6)-connected net with (611·84) (63)2 topology. The complex 5 shows a (3, 8)-connected network with a point symbol of (4·62)2 (42·615·78·8·92) topology. The complex 6 exists a 2-fold interpenetrating topology framework and the point symbol is (6·6·6). Moreover, the photocatalytic studies show that complexes 1–5 have highly photocatalytic ability to degrade methylene blue (MB). In addition, the complex 6 can efficiently adsorb Congo red through H-bonds and the adsorption kinetic have been discussed.

Six functional metal-organic frameworks constructed from semi-flexible 4,4′-bis(imidazolyl)diphenyl ether (bidpe), namely: [Zn(bidpe)(mpa)]n (1), [Cu(bidpe)(mpa)(H2O)]n (2), [Cd(bidpe)(mpa)]n (3), [Zn1.5(bidpe)2(smpa)(H2O)]n (4), [Cu1.5(bidpe)2(smpa)(H2O)]n (5), [Cd(bidpe)(hmpa)]n (6) (H2mpa = m-Phthalic acid, H2smpa = 5-sulfonatobenzene-1,3-dicarboxylate, H2hmpa = 5-Hydroxyisophthalic acid), have been synthesized under solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that complexes 1–4 and 6 show 2D→3D supramolecular structure with a Schlafli symbol of (44·62), (4·65), (44·62), (42·6) and (63) topology, respectively. Complex 5 possesses an unprecedented (3, 4, 6)-connected 3D framework with a Schlafli symbol of (4·64·8)2(42·64·89)(62·8)2. Meanwhile, complexes 1, 3, 4 and 6 have excellent fluorescence properties and can be used as potential luminescent sensors for sensing Cr(VI) anions, Fe(III) ions and nitrobenzene (NB) with high selectivity and sensitivity. The photocatalytic studies indicate that 1 has good photocatalytic capability in degradation of methylene blue (MB), 1 and 6 have good photocatalytic capability in degradation of methyl violet (MV). Furthermore, the possible sensing mechanism and photocatalytic mechanism have been discussed.

Three novel coordination polymers (CPs) based on transition metals, namely {[Cu(bpt)2(H2O)2]·2NO3}n (1), {[Cu(bpt)(SO4)(H2O)]·H2O}n (2) and [Cd(bpt)(SO4)]n (3) (tib = 1,3,5-tris(1-imidazolyl)benzene and bpt = 2,5-bis(4-pyridyl)-1,3,4-thiadiazole), have been designed and successfully synthesized under solvothermal conditions. All of these three polymers were characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction analysis reveals that complex 1 possesses a uninodal 4-connected 3D (three-dimensional) spl topology framework with the point symbol (44·62). Complex 2 showing a 1D zigzag chain, which is connected by a sulfate anion to form a 2D network, is further assembled into a 3D supramolecular structure, whereas complex 3 displays a 3D 3,5-connected tfz-d topology with chiral inorganic 2-D layers. Moreover, the photocatalytic degradation of the three complexes has been investigated. Significantly, complex 1 is the best photocatalyst for the degradation of organic dyes (MB/MV/RhB).

Four novel Zn(II) metal–organic frameworks (MOFs) including {[Zn(L)0.5(bimb)]·2H2O·0.5(CH3)2NH}n (1), {[Zn(L)0.5(bimmb)]·2H2O}n (2), {[Zn(L)0.5(btdpe)]·H2O}n (3), and [Zn(L)0.5(bidpe)]n (4) (H4L = 5,5′-(1,4-xylylenediamino) diisophthalic acid, bimb = 1,4-bis(imidazol-1-yl)-butane, bimmb = 1,4-bis(imidazol-1-ylmethyl)benzene, btdpe = 4,4′-bis(4H-1,2,4-triazol-4-yl)diphenyl ether, and bidpe = 4,4′-bis(imidazolyl)diphenyl ether) were solvothermally prepared and further characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis showed that complex 1 features a 3-fold interpenetrated bbf topological framework with the Schlafli symbol of (64·82)(66)2. Complex 2 displayed an unprecedented 2-nodal (4,4)-connected 3D framework with the Schlafli symbol of (86), while complexes 3 and 4 showed 3-nodal (2,4,4)-connected (4·8·104)2(4)2(84·10·12)-unprecedented frameworks. Luminescence studies revealed that complexes 1–4 can be used as high selectivity luminescence sensors for sensing Fe(III) cations, Cr(VI) anions (Cr2O72− and CrO42−) and nitroaromatic compounds. Furthermore, a possible sensing mechanism was investigated in this paper.

Four functional metal–organic frameworks constructed from 4,4′-(1H-1,2,4-triazol-1-yl)methylenebis(benzoic acid) (H2tmlb), namely: {[Co4(tmlb)4(H2O)]·2CH3CN·4H2O}n (1), {[Co(tmlb)(bbibp)]·1.5CH3OH·2H2O}n (2), {[Co2(tmlb)2(bimmb)]·6CH3CH2OH·4H2O}n (3), and {[Co(tmlb)(bibp)(H2O)]·DMA}n (4) (bbibp = 4,4′-bis(benzoimidazo-1-yl)biphenyl, bimmb = 1,4-bis(imidazol-1-ylmethyl)benzene, bibp = 4,4′-bis(imidazolyl)biphenyl), have been synthesized under solvothermal conditions. Four Co complexes have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). The single-crystal X-ray diffraction analysis reveals that complex 1 shows a two-fold interpenetrating (3,6,6)-connected framework with a Schlafli symbol of (4·62)2(42·610·83) topology; complex 2 shows a two-fold interpenetrating uninodal 4-connected cds topology with a point symbol of (65·8); complex 3 shows a 2D → 3D supramolecular structure through weak interactions; complex 4 shows a (3,4,6)-connected network with a point symbol of (4·62)2(42·64·93·106)(64·9·10) topology. Furthermore, the variable temperature magnetic susceptibilities of complexes 1–4 have been discussed. Complex 4 can selectively adsorb sulfate-containing dyes by Lewis acid–base interactions. And the four complexes all exhibit excellent photocatalytic capability in degradation of MB/MV.

Five novel Cd(II) metal–organic frameworks (Cd-MOFs), namely [Cd6(L)4(1,3-bit)2(H2O)4]n (1), [Cd(HL)(4,4′-bbibp)]n (2), [Cd3(L)2(1,4-bimb)2(H2O)2]n (3), [Cd(HL)(4,4′-bidpe)]n (4) and [Cd3(L)2(1,1′-bbi)(H2O)4]n (5) (flexible H3L = 5-(2-carboxylphenoxy)isophthalic acid, rigid 1,3-bit = 1,3-bis(l-imidazoly)toluene, rigid 4,4′-bbibp = 4,4′-bis(benzoimidazo-1-ly)biphenyl, semi-flexible 1,4-bimb = 1,4-bis(imidazol-l-ylmethyl)benzene, semi-flexible 4,4′-bidpe = 4,4′-bis(imidazolyl)diphenyl ether, and flexible 1,1′-bbi = 1,1′-(1,4-butanediyl)bis(imidazole)) were synthesized employing a rational design approach under solvothermal conditions and further characterized by elemental analysis, IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. Diversity architectural topologies have been generated by adjusting the N-donor ligands. They exhibit varied structures: 1 displays an unprecedented 6-nodal (3,3,4,4,8,8)-c 3D topology framework with the point Schlafli symbol of (3·4·5)2(32·42·52·66·78·87·9)(32·63·7)(4·64·8)(410·611·87)(43)2; 2 shows a 2-fold interpenetrating 4-connected cds topology with the point Schlafli symbol of (65·8); 3 exhibits an unprecedented 2-nodal (3,8)-c 3D topology network with the point Schlafli symbol of (42·5)2(44·56·610·75·82·9); 4 shows a 4-connected sql topology with the point Schlafli symbol of (44·62); 5 displays a tfz-d topology 2-nodal (3,8)-c 3D network with the point Schlafli symbol of (43)2(46·618·84). The luminescence studies reveal that MOFs 1–5 display highly sensitive and selective fluorescence sensing towards Fe3+ cations, CrO42− anions and molecular acetone. Meanwhile, the targeted dye adsorption properties of MOFs 1–5 are investigated.

Two novel coordination polymers (CPs) based on cobalt transition metal, namely {[Co(tib)2]·2HNO3}n (1) and {[Co(tib)(4,4′-sbdc)]·H2O}n (2) (tib = 1,3,5-tris(1-imidazolyl)benzene, H2sbdc = 4,4′-stilbenedicarboxylic), have been designed and successfully synthesized under solvothermal conditions, which were characterized by elemental analysis, infrared spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 features a stable 2D → 3D supramolecular frameworks through H-bonds with a rare (3,6)-connected kgd topology and complex 2 displays a 2-fold interpenetrating (2,4)-connected new topology with the point Schlafli of (44·62)(42). Importantly, the photo-catalytic properties of complexes 1–2 have been investigated, and then complex 2 is a good photo-catalyst for the degradation of mixed organic dyes (MB/MV/RhB).

Two novel luminescent coordination polymers, namely, {[Zn(tmlb)(H2tmlb)]·H2O}n (1) and [Zn(tmlb)(bbibp)]n (2) ((bbibp = bis(benzoimidazo-1-ly)biphenyl), H2tmlb = (1H-1,2,4-triazol-1-yl)methylenebis(benzoic acid)), have been rationally designed and successfully solvothermally synthesized. Complexes 1 and 2 have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). Complex 1 possesses a 2-fold interpenetrating 3-connected 3D framework with a point symbol of (63) topology. Complex 2 exhibits a two-fold interpenetrating uninodal 4-connected 3D framework with a (65·8) topology. The luminescence studies reveal that complexes 1 and 2 display highly sensitive and selective luminescent sensing towards Cr(VI) (CrO42− and Cr2O72−) anions, and complex 2 displays highly sensitive and selective luminescence sensing towards Fe(III) cations. In addition, photocatalytic studies show that complex 1 could be a good candidate for the photocatalytic degradation of methylene blue (MB), and complex 2 could be a good candidate for the photocatalytic degradation of methylene violet (MV) and Rhodamine B (RhB).

Four novel Co(II) metal–organic frameworks, namely [Co2(4,4′-cpmb)2(1,1′-bbi)2]n (1), [Co(4,4′-cpmb)(4,4′-bbibp)]n (2), {[Co(4,4′-cpmb)(tib)]·3(H2O)}n (3) and {[Co(4,4′-sdc)(tib)]·(H2O)}n (4) (flexible 4,4′-cpmb = 4-(4-carboxylphenylmethylthio)benzoic acid, rigid 4,4′-sdc = 4,4′-stilbenedicarboxylic acid, flexible 1,1′-bbi = 1,1′-(1,4-butanediyl)bis(imidazole), rigid 4,4′-bbibp = 4,4′-bis(benzoimidazo-1-ly)biphenyl and rigid tib = 1,3,5-tris(1-imidazolyl)benzene) were synthesized employing a rational design approach under solvothermal conditions and further characterized by elemental analysis, IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. The four Co-MOFs display different interpenetrated structures due to the flexibility of O/N-donor ligands. Single-crystal X-ray diffraction analysis reveals that complex 1 displays a 6-fold interpenetrating class Ia net with the point Schlafli symbol of (66). Complex 2 shows a 3-fold interpenetrating sqc5 net with the point Schlafli symbol of (66·8). Complexes 3 and 4 exhibit a 2-fold interpenetrating 4-connected sql topology with the point Schlafli symbol of (44·62). The photodegradation properties and dye adsorption capacity of complexes 1–4 are investigated, and the framework integrity of complexes 1–4 can be well-retained.

Three novel Mn(II)/Co(II)-based 3D metal-organic frameworks (MOFs), namely {[Mn2(L)(tib)(H2O)]·3DMA·4H2O}n (1), {[Co2(L)(bipd)2]·3H2O}n (2) and {[Co(L)0.5(bimb)]·3H2O·0.5O2}n (3) (H4L ​= ​5,5'-(1,4-xylylenediamino) diisophthalic acid, tib ​= ​1,3,5-tris(1-imidazolyl)benzene, bipd ​= ​3,5-bis(1-imidazoly)pyridine, and bimb ​= ​1,4-bis(lmidazol)-butane), have been successfully synthesized using the mixed-ligand as functionalized organic linker. The structural characterization revealed that both MOFs 1 and 2 exhibited an unprecedented 4-nodal 3D framework that enriching crystal engineering, while MOF 3 featured a 2-nodal three-interpenetrating bbf topology framework with a Schlafli symbol of (64·82)(66)2. The title MOFs have been exploited as photocatalysts for degradation of methylene blue (MB), methyl violet (MV) and malachite green (MG). The photocatalytic results demonstrated that MOFs 2 and 3 exhibited efficient photocatalytic abilities to degrade the three aromatic dyes under UV irradiation. The possible catalytic mechanism was also explored and discussed in detail. Moreover, the variable-temperature magnetic analyses indicated that MOFs 1–3 exhibited weak antiferromagnetic behavior between Mn(II)/Co(II) ions.

Either reduced or excessive metal ions level in biological systems might induce serious metabolic diseases, and the abuse of antibiotics has seriously affected the environment. Despite the significant progress in the development of fluorescence probes over the past decade, the ability to sensitively and selectively detect these metal ions and antibiotics remains a pressing problem. Herein, we demonstrated some effective fluorescence probes for sensing metal ions and antibiotics, six novel and stable Zn(II) metal-organic frameworks (Zn-MOFs), namely [Zn

In this work, five novel Cd/Zn-based MOFs with different topological framework, namely {[Cd(bimb)(Hbipa)]·H2O}n (1), {[Cd3(dimb)3(bipa)2(H2O)2]·2H2O}n (2), [Cd(bimd)(Hbipa)(H2O)]n (3), {[Zn(bipd)(Hbipa)]·H2O}n (4) and [Zn(bimb)(Hbipa)]n (5) had been synthesized and characterized. Worth noting, Complex 1 and 2 had effective separation behaviors towards MO and MBE dyes respectively, which could reach the adsorption equilibrium within a quite short time even if there existed another kind of dye in the system. Meanwhile, Complex 3–5 showed great performance in CR adsorption. Additionally, Complex 3–5 also showed excellent photocatalytic degradation capabilities toward MB and MV dyes under UV irradiation. According to the study, these five metal-organic frameworks can be used as a kind of functional materials in the adsorption and photocatalytic degradation of organic dyes in wastewater.

Three new Zn metal organic frameworks (Zn-MOFs), {[Zn2(L)[H (1,4-bmib)]]·1.5(H2O)}n (1), {[Zn2(HL) (3,5-bip)2]·(H2O)}n (2), and {[Zn2(HL) (4,4′-bbibp)2]·4(H2O)}n (3), have been first synthesized based on a flexible H5L ligand with ether functional group (C–O–C) and successfully characterized (semi-flexible H5L ​= ​3,5-bis(3,5-dicarboxylphenoxy)benzoic acid, flexible 1,4-bmib ​= ​1,4-bis(2-methylimidazol-1-yl)butane, rigid 3,5-bip ​= ​3,5-bis(1-imidazolyl)pyridine, and rigid 4,4′-bbibp ​= ​4,4′-bis(benzoimidazo-1-ly)biphenyl). Zn-MOFs 1–3 are unique topological networks. As multi-responsive fluorescent sensing materials of 1 and 3, they show excellent response and sensitivity for Fe3+, CrO42− and Cr2O72−, and tetracycline (TC) in aqueous system. The quenching mechanism is also investigated in detail.

A multi-responsive fluorescence probe NPH was rational configured on the receptor1-fluorophore-receptor2 model to discriminatively detect Al3+, Mg2+ and Zn2+. The probe NPH contained benzooxazole moiety (receptor1) and 2-aldimine-phenol unit (receptor2), which showed fluorescence “turn on” response for Al3+, Mg2+ and Zn2+ in DMF/H2O (9/1, V/V, pH = 7.4) medium and sensing mechanism was studied by 1H NMR, FT-IR and further confirmed by DFT calculation. The presence Mg2+ inhibited ESIPT and C = N isomerization processes, but the presence Al3+ caused a moderate deprotonation of the naphtholic OH. Finally, the presence of Zn2+ completely deprotonated the naphtholic OH and phenolic OH. The presence of Al3+, Mg2+ and Zn2+ resulted in the different degree deprotonation processes, which resulted the fluorescence responses at different emission wavelength. Interestingly, after addition of EDTA to the NPH/Al3+ complex, caused a new and strong emission peak at 560 nm along with a remarkable color change from yellow-green to yellow-orange, and the value of fluorescence intensity at 560 nm was linearly proportional to the concentration of EDTA. The NPH/Al3+ complex could serve as a fluorescence colorimetric probe for the detection EDTA. In addition, probe NPH was applied in real water samples and construction of molecular logic gate. Importantly, fluorescence image experiments of Al3+, Mg2+, Zn2+ and EDTA in living HeLa cells and HepG cells confirmed its value in biological system.

Two novel Co-MOFs constructed from aromatic polycarboxylic acid named {[Co(tib)2(bimb)2]·4H2O}n (tib = 3-((4-(1H-1,2,4-triazol-1-yl)benzyl)oxy)benzoic acid, bimb = 1,4-bis(imidazole-1-ylmethy) benzene) and {[Co2(bipa)4(bibp)6]}n (bipa = 2-(4-carboxy-2-nitrophenoxy)-6-nitroterephthalic acid, bibp = 4,4′-bis(imidazolyl) biphenyl), have been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra, powder X-ray diffraction (PXRD), thermogravimetric analysis (TG) as well as electrochemistry. The single-crystal X-ray diffraction analysis indicates that Co-MOF 1 exhibits an uninodal net with a (65·8) topology, whereas Co-MOF 2 exhibits an uninodal 4-connected framework with a (44·62) topology. The electrochemistry studies demonstrate that both of the two Co-MOFs can behave as the efficient electrocatalysts for water oxidation in a mild neutral system at the potential around 1.20 V vs. NHE with comparatively low overpotential (η) for Co-MOF 1 and 2 of 337–541 mV vs. NHE. Moreover, the two Co-MOFs also show good photocatalytic degradation capabilities toward MB/MV dyes under UV irradiation, and the mechanism studies demonstrate that the main active species are ·OH radicals. Therefore, these bi-functional Co-MOFs materials can be treated as convenient and efficient catalysts for the oxygen evolution reaction and aromatic dyes degradation.

Assembled from O-containing pentacarboxylate acid ligand (H5L), two new water-stable Cd organic frameworks (Cd-OFs), namely {[Cd4L2]·1,4-bmib}n (1) and [Cd4L2(1,4-bimb)3]n (2) have been solvothermally synthesized and further characterized. Cd-OF 1 possesses a rare 2-nodal (5,10)-c fit topological 3D network based on tetranuclear [Cd4(µ3-O)4(COO)10]2− unit. Cd-OF 2 displays an interesting 2D → 3D interdigitating and penetrating structure with a unique 3-nodal (3,3,5)-c topological framework. The luminescence performance of Cd-OFs 1–2 has been investigated based on their high thermal and good chemical stability. These results reveal that 1–2 can serve as multi-responsive luminescent sensors for tetracycline (TC), Cr2O72− and Fe3+ ions with excellent selectivity and highly sensitive sensing ability. Interestingly, the Cd-OF 2-coated fluorescent test papers can be used to detect TC, Cr2O72− and Fe3+ ions in water system, and thus may have promising application prospect.

Two novel metal-organic frameworks (MOFs) based on transition metals, namely [Ni(sbdc)(4,4′-bbibp)(H2O)2]n (1) and [Co(sbdc)(4,4′-bbibp)]n (2) (H2sbdc = 4,4′-stilbenedicarboxylic, 4,4′-bbibp = 4,4′-bis(benzoimidazo-1-ly)biphenyl), have been designed and successfully synthesized under solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that complex 1 features a 5-fold classical Ia interpenetrated dia framework with 4-connected (66) sqc6 topology and complex 2 displays a 7-fold classical Ia interpenetrated dia network. Further, the photocatalytic properties of complexes 1–2 have been investigated. Significantly, the complexes 1–2 are good photo-catalysts for the degradation of organic dyes (MB/MV/RhB).

A new complex, Ni(C22H26N2O10S2)·2CH3OH, with a sexidentate (N2O4) symmetric bis-Schiff base ligand (C22H26N2O10S2 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane-2-aminoethane-sulfonic acid) has been synthesized and characterized by physico-chemical and spectroscopic methods. The X-ray crystal structure shows that the Ni(II) atom of the complex is six-coordinated by two nitrogens from C N groups, two oxygens from ether groups and two hydroxyl oxygens from sulfonic acid groups in the mono-ligand, forming a distorted octahedral geometry. Theoretical study of the complex is carried out by density functional theory (DFT) method and the B3LYP method employing the 6-3l+G* basis set. Moreover, the complex proved to be good candidate for the photocatalytic degradation of methylene blue.

We reported a sensor BZH bearing AIE (aggregation-induced emission) characteristics in solid state and aqueous ethanol solution. In EtOH/H2O (1/9, V/V) medium, BZH possessed spherical shape with the average diameter of ~142 nm due to the unique dimer formation by intermolecular hydrogen bonds, and exhibited fluorescence ratiometric response to Erythromycin, Zn2+ and Cd2+ and UV–vis ratiometric behavior to Cu2+ along with remarkable naked-eye color changes, respectively. The binding stoichiometry of BZH to Erythromycin was 2:1, but that to metal ions was 1:1. The BZH towards Erythromycin and metal ions showed different sensing mechanisms, and were confirmed by job'plot, 1H NMR FT-IR, ESI-MS, DLS and TEM. The presence of Erythromycin triggered the ESIPT process and induced new intramolecular hydrogen bond formation, but the presence of metal ions (Zn2+, Cd2+ and Cu2+) caused deprotonation processes, these caused the BZH dimers' dissociation and consequently induced monomer emission. Meanwhile, the morphology of BZH changed from spherical to flower shape for Erythromycin and block shape for metal ions, indicating the Erythromycin and metal ions with BZH monomer further formed new aggregates, respectively. Furthermore, the BZH was applied to detect Erythromycin, Zn2+, Cd2+ and Cu2+ in actual water samples and Hela cells.

An efficiently selective sensor for aquatic antibiotic detection based on a photoluminescent cadmium metal–organic framework (Cd-MOF) is researched in this work. The novel and simple luminescent MOF that composed from a π-electron rich ligand bip (3,5-bis(1-imidazol) pyridine) and H3L (2-nitro-5-(4-carboxy-2-nitrophenoxy) isophthalic) was synthesized in hydrothermal condition and characterized. Single crystal X-ray diffraction analysis demonstrated that it had an uncommon 2-nodal (3,6)-connected 3D framework with a (32·4)(34·46·53·62) topology, which could be formulated as [{[Cd2(HL)2(bip)2]·H2O}n]. Benefiting from its unique framework, [{[Cd2(HL)2(bip)2]·H2O}n] can not only respond to the trace quantity of chloramphenicol (CHL) via fluorescence quenching but also show good adsorption capability toward CHL in aqueous solution. The selective response to CHL reached up to the ppb level with high anti-interference ability in aqueous phase, and the effective detection of antibiotics had been theorized by Density Functional Theory (DFT) calculation for energy bands of H3L and antibiotics, which revealed that the cooperation influence on photo-induced electron transfer (PET) process and fluorescence inner filter effect (IFE) made CHL show more sensitive luminescence responses than other experimental antibiotics. Moreover, because of its specific interactions with analytes and relatively high porosity, the pre-enrichment makes the antibiotic fuller contact and interact with the framework, which improves the overall sensing efficiency towards CHL appreciably. Stemming from the abuse, antibiotics have been considered as the great threat to the health of human race and the sustainable development of society. Therefore, it is extremely important to achieve new technology to detect and absorb antibiotics residues in water. This work proves that metal–organic framework complexes can conform the performance of detecting and removing antibiotic in aqueous environment, that emphasizes the application of luminescent MOFs in contaminant monitoring and removing.

In this study, we have synthesized six new coordination polymers (CPs), namely {[Cu6(3,5-bip)6(H2O)12(SO4)6]·3H2O}n (1), [Co(3,5-bip) (H2O)3(SO4)]n (2), {[Cu(1,3-bit)2(H2O)2]·2(NO3)}n (3), {[Cu2(1,3-bit)2 (1,3-bcbb)2]·4(H2O)}n (4), [Cu(4,4′-bibp) (H2O) (NO3)2]n (5), [Cu(4,4′-bibp) (4,4′-Hsbdc)]n (6) via solvothermal methods. The structures of these new CPs have been characterized by elemental analysis, FTIR, TG analysis, PXRD and single crystal X-ray diffraction techniques. Meanwhile, the title CPs are explored for adsorption of organic dyes, i.e., anionic dyes (congo red (CR), and methyl orange (MO)) and cationic dye (methylene blue (MB)) considered extensively as water colorants pollutants. Worth noting, complex 3 can adsorb anionic dyes (CR and MO) quickly; complex 6 shows great performance in CR adsorption. Kinetic study reveals that the adsorption process is performed via pseudo-second-order reaction. The dye removal investigations of complexes 3 and 6 support that ions exchange and H-bonding interactions between CPs and target organic dyes are significant factors, heavily affecting dye adsorption. They have excellent potential in wastewater treatment.

Two novel Co(Ⅱ)-MOFs synthesized under solvothermal conditions, namely [Co3(L)2(bimb)2(H2O)2]n (OUC-1) and [Co2(L)(OH)(H2O)2]n (OUC-2) (bimb = 1,4-bis(lmidazol)butane, H3L = 3-(3,5-dicarboxylphenoxy)-5-carboxylpyridine), were used to remove Congo Red and Orange Ⅳ from aqueous environment, respectively. The influential parameters of the temperature and pH of solution, initial dye concentration, the structure and charge of dye on the adsorption performance were investigated. It is found that the dye with proper structure (i.e. organic groups favorable for adsorption, such as -NH2, -SO3H, etc, proper distance between the groups, linear structure and more benzene rings), richer negative charges, smaller molecular weight facilitates faster adsorbed. The intermittent operation experiments were adopted to make the adsorption isotherm and kinetics data of OUC-1 and OUC-2 accurately described by Langmuir isotherm and pseudo second-order kinetics. The intra-particle diffusion model indicates the adsorption process is controlled by the intra-particle diffusion and other adsorption stages. Two adsorbents release azo dyes easily through simple organic solutions and maintain high adsorption capacity after 8 cycles. Moreover, OUC-1 and OUC-2 also exhibit high adsorption performance in artificial seawater. The mechanism of selective adsorption involves pore filling, π-π stacking interaction, hydrogen bond and electrostatic interaction.

Five novel coordination polymers based on the 2,6-pyridinedicarboxylic acid (H2pdca), namely [Co(pdca)(bibp)0.5H2O)2]n (1), [Ni(pdca)(bibp)0.5(H2O)2]n (2), [Co(pdca)(bbibp)1.5]n (3), [Ni(pdca)(bbibp)1.5]n (4) and Zn(pdca)(bbibp)0.5]n (5) (bibp ​= ​4,4′-bis(imidazole) biphenyl, bbibp ​= ​4,4′-bis(benzoimidazo-l-yl)biphenyl and DMF ​= ​N, N’dimethylformamide) have been synthesized under solvothermal conditions. Single crystal X-ray diffraction analysis reveals that all the complexes have 3D framework structures. In addition, the properties of the complexes for photo-catalytic degradation of organic dyes were discussed. Moreover, luminescence studies reveal that complex 5 shows strong luminescent property and could be a fluorescence sensor for the detection of Cr2O72−ion and antibiotics chloramphenicol. The Ksv values of 5 for Cr2O72− ion and chloramphenicol are 8.05 ​× ​103 ​M−1 and 6.69 ​× ​103 ​M−1, respectively. Meanwhile, the possible mechanism for the luminescence quenching of 5 has been discussed.

Three novel Zn(II)-based coordination polymers (Zn-CPs), namely {[Zn(1,3,5-tib)2(H2O)2]·2(NO3)}n (1), [Zn(1,3,5-tib)(4,4′-saba)]n (2), and {[Zn(1,3-bit)(4,4′-cpmb)]·0.5(1,3-bit)}n (3), have been hydrothermally synthesized and successfully characterized by single crystal X-ray diffraction (1,3,5-tib ​= ​1,3,5-tris(1-imidazolyl)benzene), 4,4′-Hsaba ​= ​4-(4-sulfoacid)-benzoic acid, 1,3-bit ​= ​1,3-bis(l-imidazoly)toluene, and 4,4′-H2cpmb ​= ​4-(4-carboxylphenylmethylthio)benzoic acid). Structural analysis reveals that complex 1 manifests a 2D planar structure with an unprecedented (2,4)-c topological network. Complex 2 and complex 3 display a 3-c fes and 6-fold classical Ia interpenetrated dia framework with 4-c (66) sqc6 topology framework, respectively. Among the three complexes, CPs 1 and 2 demonstrate excellent performance for Azo organic dyes’ adsorption, for which the selectivity and kinetics have been comprehensively studied. CPs 3 shows great luminescent intensity in aqueous solution. It is further applied as a fluorescence sensor to detect Fe3+ cation, Cr2O72− anion, and tetracycline antibiotic.

In this work, naphthalene with good biocompatibility was selected, and the probe NBOS was synthesized with 2-Amino-phenol and 2-Amino-benzenethiol. The structure of probe NBOS was confirmed by X-ray Crystallography. Furthermore, the probe showed absorbance-ratiometic sensing for Ag+ over a pH range from 6 to 7.5 and fluorescence “turn on” signal response towards Zn2+ in the pH range of 6–10 in EtOH/H2O (9/1, V/V, pH = 7.4) mixture. The detection limit was obtained to be 4.24 μM for Ag+ and 3.17 nM for Zn2+. Moreover, it could be efficiently recycled by treating Na2EDTA. The sensing mechanism of probe NBOS toward Ag+ and Zn2+ was investigated by FT-IR, HNMR, job’plot and ESI-MS. Typically, the coordination mode of NBOS with Zn2+ was confirmed by DFT calculation. Moreover, probe NBOS was successfully applied in the detection Ag+ and Zn2+ in real water samples. Importantly, probe NBOS could be used to detect Zn2+ in walnut and living cells. Based on the high throughput analysis strategy, absorbance and fluorescence signals of NBOS could be designed as a NOT and OR logic gate controlled by Ag+ (Input 1) and Zn2+ (Input 2).

Four novel Co(II) coordination polymers (CPs) based on a “V”-shaped 1,3-di(4′-carboxyl-phenyl)benzene acid (H2dpb), namely {[Co2(dpb)2(4,4′-bibp)2]·2(CH3CN)}n (1), [Co(Hdpb)2(4,4′-bibp)]n (2), {[Co2(dpb)2(tib)2]·H2O}n (3) and {[Co(dpb)(bimb)0.5]·DMF·0.5(CH3CN)}n (4) (4,4′-bibp = 4,4′-bis(imidazol-1-yl)biphenyl, tib = 1,3,5-tris(1-imidazolyl)benzene and bimb = 1,4-bis(imidazol-1-ylmethyl)benzene), have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 possesses a uninodal 4-connected 3D (three-dimensional) cds topology framework with the Schlafli symbol (65·8). Complex 2 shows 1D zigzag chains, which are further assembled into a 3D supramolecular structure by O–H⋯O hydrogen bonds. Complex 3 shows an unprecedented 3-nodal (3,4,6)-connected 3D framework with the Schlafli symbol (62·7)2(64·75·84·9·10)(64·82), while complex 4 displays a {Co2(COO)4} binuclear SBU-based 3D 6-connected (44·611)-unprecedented framework. Moreover, the photocatalytic degradation of the four Co(II) compounds (complexes 1–4) has been investigated.

Two novel coordination polymers, namely {[Zn(sbdc)(bmib)]·0.4H2O}n (1) and {[Zn(sbdc)(bibd)]·DMF}n (2) (H2sbdc = 4,4′-stilbenedicarboxylic, bmib = 1,4-bis(2-methylimidazol-1-yl)butane, bibd = 1,1′-(1,4-butanediyl)bis(imidazole), DMF = N,N-dimethylformamide), have been acquired under solvothermal conditions, and have been characterised by elemental analysis, infrared spectra, thermogravimetric analysis, and single-crystal X-ray diffraction (XRD). Single-crystal XRD analysis reveals that 1 shows eight-fold interpenetrating 3D frameworks with a four-connected (66) sqc6 topology and 2 displays four-connected three-fold interpenetrating 3D frameworks. The flexible N-donor ligands play an important role in the construction of the final topological structures for 1 and 2. Furthermore, 1 and 2 exhibit good photodegradation capability and photoluminescence properties.