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Three new complexes, namely, [Cu2(H2bdcpb)2(pyridine)2] (1), [Cu3(bdcpp)2(CH3NCH3)(H2O)] (2), and [Cu2(H2bdcpp)2(H2O)2]·2H2O (3), have been synthesized through the hydro/solvothermal reaction of cu...

Suitable chemical components in water systems for human health are a crucial prerequisite for mankind's survival. Simple and effective innovations are being developed to efficiently monitor healthy and toxic substances. Here, with a hydrothermal technique, a novel thermostable metal–organic framework (MOF) [Cd2(L)(bib)0.5(H2O)3]n·1.75n(H2O) (MOF-1, H4L = biphenyl-2,3,3′,5′-tetracarboxylic acid, bib = 1,4-bis(imidazolyl)butane) was designed and synthesized. MOF-1 shows a 4,5-connection binodal 3D fsx-type topological net with irregular cages, which the bulk materials show high phase purity, excellent thermo/aqua-stability and intense fluorescence. The luminescent MOF was studied for the highly sensitive detection of trace amounts of Fe3+ ions and nitrobenzene and shows high KSV values of 4.653 × 104 and 5.724 × 104, respectively. It was also demonstrated that MOF-1 possesses superior probing ability towards nine other nitroaromatic explosives with remarkable quenching percentages. These results offer a new possibility for the potential multiple recognition of various chemical substances in human body and water systems by utilizing novel dual-functionalized luminescent MOF sensors.

A novel in situ cyclocondensation reaction of anp (anp = 2-amino-5-nitropyridine) and ethanol into L (L = 6-nitro-imidazo(1,2-a)pyridine) under solvothermal conditions has been observed for the first time. Crystal structure of a metal complex, CdL2I2 (1), has been obtained. Complex 1 was synthesized from a solvothermal reaction of anp with CdI2 in anhydrous ethanol and water. Complex 1 crystallizes in orthorhombic space group Pnma with a = 13.662(9) A, b = 16.734(11) A, c = 8.767(5) A. The structure of 1 shows mononuclear units. Weak hydrogen bonds and π···π stacking intermolecular interactions assemble units to form a 3-D supramolecular network of 1.

A novel 3D NbO metal-organic framework, [Cd2(pam)2(bpt)2(H2O)]n·0.68nH2O (1) (H2pam = pamoic acid and bpt = 2,5-bis(4-pyridyl)-1,3,4-thiadiazole), has been synthesized by the structural cooperation of well-chosen flexible aromatic acid and rigid bipyridyl ligand. The rare severely distorted mixed-ligand mesomeric networks accommodate two individual heterochiral frameworks interpenetrating with each other. The bulk materials of 1 display excellent fluorescent properties.

A three-dimensional Cd(II)–organic framework, formula as [Cd(tib)2∙(NO3)2]∙4DMF (tib = 1,3,5-tri(1H-imidazol-1-yl)benzene and DMF = N, N-dimethylformamide), has been successfully constructed by solvothermal synthesis. The as-made complex has been investigated and characterized by single X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analyses, luminescent spectra, and UV-Vis adsorption spectra. By virtue of its stability and luminescent property, this complex can used as a luminescent sensor toward picric acid and nitrofurantoin. The calculated KSV value is approximate 1.29 × 104 M–1 with the R2 value of 0.9946 for picric acid and 3.02 × 104 M–1 with the R2 value of 0.9973 for nitrofurantoin. Meanwhile, this as-synthesized complex has good recyclability.

From the same starting materials, two novel metal–organic frameworks, namely {(cation)[Cu4(bptca)2(OH)(H2O)2]·x(solvent)}n (1) and {(cation)[Cu3(bptca)2(H2O)3]·y(solvent)}n (2) (H4bptca = biphenyl-2,3,3′,5′-tetracarboxylic acid), have been synthesized through the linkage of Cu2(COO)4 paddle-wheel clusters. The complex 1 possesses both dinuclear [Cu2O2] subunits encapsulated into cage-like units and tetranuclear [Cu4(μ3-OH)2] clusters, which exhibits an unusual 3D 4-nodal (4,4,4,8)-connected network with {412.812.104}{43.83}4{46}{86} topology. Reducing the metal-to-ligand ratio, the other 3D (4,4)-connected framework 2 with {42.84} PtS-type topology was constructed under the intervention of mononuclear Cu(bptca)2 and single Cu2(COO)4 paddle-wheel supporting layers. Notably, both of the frameworks 1 and 2 accommodate infinite open 1D nanosized quadrate channels.

Two new coordination polymers, namely [Ag(L)]n (1) and [Cd(L)2(bpe)]n (2) [HL = 2-fluoroisonicotinic acid, bpe = 1,2-bi(4-pyridyl)ethylene], have been synthesized by solvent evaporation and layered-diffusion technique, respectively. The structural analysis revealed that compound 1 is a linear chain structure, whereas compound 2 shows a 1D ladder-like structure with dinuclear [Cd(COO)2] stretched by bpe linkers in parallel arrangement. The thermal stability and photoluminescent properties of both 1 and 2 in the solid state were also investigated, which demonstrated the perfect thermal stability and a certain degree of redshift fluorescent characteristic. Two Ag(I)/Cd(II) CPs were synthesized by solvent evaporation and layered-diffusion technique. Both CPs were characterized by elemental analysis, FT-IR, single-crystal XRD, PXRD and TGA techniques. The solid state photoluminescent study indicates those have strong fluorescent emissions.

Solvothermal reaction of Cd(OAc)2·2H2O and biphenyl-2,3,3′,5′-tetracarboxylic acid (H4bptca) in DMF/H2O afforded one novel coordination polymer [Cd4(bptca)2(DMF)4]n (1). X-ray structural analysis reveals that complex 1 is a chiral bilayer supported by rare asymmetrical tetranuclear [Cd4(μ3-O)2(μ2-O)]. Topologically, the net can be considered as a 3,6-connected Shubnikov plane with the Schlafli symbol {43}2{46.66.83}. Further, the overlapping of 2D grids gives an open 3D framework with 1D channels occupying by dangling DMF. The physical studies of complex 1 showed the good thermal stability and fluorescent properties. One novel 2D Cd(II) chiral coordination polymer with biphenyltetracarboxylate was synthesized and structurally characterized. The bilayering net supported by the rare asymmetrical tetranuclear cluster [Cd4(μ3-O)2(μ2-O)], can be considered as a 3,6-connected Shubnikov plane with the Schlafli symbol {43}2{46.66.83}. The overlapping of 2D grids gives an open 3D framework with 1D infinite channels occupying by terminal DMF moieties. The physical studies of complex 1 showed the good thermal stability and fluorescent properties.

Four new congenetic zinc(II) MOFs, namely [Zn5(bdcpp)3(DMF)(H2O)4]n·x(solvent) (1), [Zn2(bdcpp)(Hbdcpp)]n·y(solvent) (2), [Zn2(bdcpp)(DMF)(H2O)2]n (3), and [Zn2(bdcpp)(NMP)(H2O)2]n (4) (H4bdcpp = 2,6-bis(2′,4′-dicarboxylphenyl)pyridine, DMF = N,N'-dimethyl formamide, NMP = N-methyl-2-pyrrolidone), have been synthesized solvothermally with different solvent systems. Stabilized by Zn2(COO)4 paddle-wheel building blocks, the resulting MOFs 1–4 represent diverse structural features. Structurally, 1 is a rarely 3,4-c binodal 2D bilayered framework, 2 possesses a 4-c 2D (4,4) sql planar network accommodating two kinds of hetero chiral helix chains, 3 and 4 are isostructural 1D loop ladder chains except different solvent molecules occupying the axial terminals of Zn2(COO)4 paddle-wheels. This approach based on solvent-regulated strategy aiming to allow the structural fine-tuning provides a good role model in reticular chemistry. Complexes 1–3 display excellent solid-state photoluminescence stemming from the metal-to-ligand charge transfer or intraligand charge transmission.

A rutile topological 3-D metal organic framework (MOF) has been obtained by reacting CdSO4·8/3H2O with HL (HL = 6-aminonicotinic acid) under solvothermal conditions. Unique right- or left- handed helices can be found in the architecture of the MOF. The framework can exhibit tunable UV-to-visible fluorescence by variation of the excitation light.

An excellent one-center-acceptor–donor ligand, 2-aminoisonicotinic acid, was successfully employed to obtain an acentric 3-D metal–organic framework, which exhibits a unique threefold interpenetrated diamondoid network, second-harmonic-generation response, potential ferroelectric behaviors and photoluminescence.

A new lead coordination polymer [Pb2(mip)2] (1) has been synthesized under the intervention of polycarboxylic acid by hydrothermal method (H2mip = 5-methylisophthalic acid). X-ray single-crystal structure determination reveals that the polymer crystallizes in monoclinic C2/c space group: a = 21.118(2) A, b = 8.0055(7) A, c = 25.556(3) A, and β = 111.1730(10)°. The Pb(II) cations are connected by four mip anions to produce a 2D (6,3) double-layered framework. It should be noted that four-membered rings by two Pb atoms with two μ-O atoms of mip groups link each other to form a one-dimensional Pb–O chain through a corner-sharing Pb center.

Assembly of 5-methoxyisophthalic acid (H2moip) with cadmium(II) ions in the presence of neutral ancillary 1,3-bis(4-pyridyl)propane (bpp) yields a new coordination polymer, [Cd(moip)(bpp)(H2O)]n·nH2O (1). X-ray single-crystal diffraction determination reveals that complex 1 crystallizes in the space group C2/c of monoclinic crystal system: a = 14.545(2), b = 18.749(3), c = 17.359(3) A, β = 105.480(2)o. Complex 1 is a 4-connected 3D diamondoid topological framework with a 2-fold interpenetration. Interestingly, the dense adamantine cages with inherent microporous structure are filled with free water molecules to further stabilize the coordination network.

A novel bent-shaped derivative, 2-thiomethyl-4,6-bis(4-N,N-methylaminostyryl) pyrimidine (TMAP) has been successfully synthesised and fully characterised by elemental analysis, IR, 1H NMR and MS. The molecule possesses D–π–A–π–D structures. Dimethylamino is used as the donor (D), and the pyrimidine ring is used as the acceptor (A). One- and two-photon absorption and fluorescence in various solvents were experimentally investigated. The chromophore shows intense single-photon excited fluorescence (SPEF) and two-photon excited fluorescence (TPEF) in a wide spectral range, with the spectral peak position of the SPEF being basically the same as that of the TPEF. The chromophore combines well with peak TPA cross-sections (up to 352.0 GM) and broad TPA bands throughout the whole 700–900 nm range and high-fluorescence quantum yields could thus be obtained. The theoretical and experimental studies indicate the charge transfer from donor to acceptor.