•A fluorescence probe for Hg2 + and Zn2 + ions was designed and synthesized.•The geometry optimizations were carried out using the Gaussian 09 program based on DFT.•The method exhibited high selectivity and sensitivity, wide range of linear response and low detection limit.•The fluorescence chemosensor can be used for imaging of metal ions in living cells.A fluorescence probe has been designed and synthesized, and applied with a combined theoretical and experimental study. Research suggests that the probe can be used to sense Zn2 + and Hg2 + through selective turn-on fluorescence responses in the aqueous HEPES buffer (0.05M, pH = 7.4). The limit of detection (LOD) were determined as 1.46 × 10− 7 M (Zn2 +) and 2.50 × 10− 7 M (Hg2 +). Moreover, based on DFT, the geometry optimizations of probe 1, [1-Hg2 +] complex and [1-Zn2 +] complex were carried out using the Gaussian 09 program, in which the B3LYP function was used. The electronic properties of free probe 1 and the metal complexes were studied based on the Natural Bond Orbital (NBO) analyses. The probe 1 has also been successfully applied to detection of Zn2 + and Hg2 + in living cells.Download high-res image (71KB)Download full-size image

A three-phase hollow fiber liquid-phase microextraction (HF-LPME) was used to determine the trace amounts of Lead (II) in environmental water and tea drinks. In this approach, green solvent ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF6) was used as membrane carrier that dissolved in hollow fiber pores. 1-(2-Pyridylazo)-2-naphthol (PAN) was placed in aqueous solution to form hydrophobic complex with Pb(II). Ethylene diamine tetraacetic acid (EDTA) was used as stripping agent that it can form water-soluble complex with Pb(II). After extraction, the acceptor solution was directly injected into the graphite furnace atomic absorption spectrometry (GF-AAS) for analysis. Some important parameters that influence the extraction efficiency were investigated, such as PAN concentration, pH, EDTA concentration, stirring rate, extraction time, and interfering metal ions. Under the optimized conditions, an enrichment factor (EF) of 210 and a limit of detection (LOD) of 0.004 ng mL−1 were obtained. The calibration curve was linear in the range of 0.05–0.5 ng mL−1 (R = 0.999). The relative standard deviation (RSD) at the 0.12 ng mL−1 Pb(II) level is 4.5 % (n = 6). The proposed method was successfully applied to determination of Pb(II) in environmental water and tea drinks samples with satisfactory recoveries in the range of 94–105 %.

Six new metal–organic coordination complexes, [Cd(MEDPQ)(2,5-pydc)]n (1), [Cd2(MOPIP)2(2,5-pydc)2]n (2), [Cu2(MOPIP)2(2,5-pydc)2]·H2O (3), [Mn(MOPIP)2(2,5-pydc)]·3H2O (4), [Cd(MOPIP)2(2,6-pydc)]·3H2O (5) and [Cd2(MOPIP)2(2,3-pydc)2·H2O]n (6) (MEDPQ = 2-methyldipyrido[3,2-f:2′,3′-h]quinoxaline, MOPIP = 2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, 2,5-H2pydc = pyridine-2,5-dicarboxylic acid, 2,6-H2pydc = pyridine-2,6-dicarboxylic acid, and 2,3-H2pydc = pyridine-2,3-dicarboxylic acid), have been prepared through hydrothermal reactions. The transformation of coordination modes of transition metal ions and organic carboxylate ligands has a crucial influence on the multinuclear structures of these series. In compounds 1 and 2, binuclear Cd(II) subunits occur, which are connected by 2,5-pydc anions to construct an undulating network. By selecting the different transition metal ions, we get the compounds 3 and 4. For the compound 3, the Cu(II) centers are linked by 2,5-pydc ligands to form a binuclear dimer. Compound 4 shows a mononuclear compound. For complexes 5 and 6, by changing the dicarboxylate ligands, Cd(II) adopts a heptacoordinated mode to form a mononuclear compound and chain framework. In addition, fluorescent properties of 2–4 have been reported.Under hydrothermal conditions, we prepared five new metal–organic coordination complexes by combining transition metal salts together with organic carboxylate anion ligands. Different metal centers (Cd, Cu and Mn) adopt variable coordination numbers and versatile coordination modes to construct complexes 2–4 with different structures and dimensions. The 2,5-H2pydc, 2,6-H2pydc and 2,3-H2pydc possess different steric hindrance, which result in the different coordination modes of the carboxylate ligand. Three types of coordination structures (layer, cluster and chain) have been observed in complexes 2, 5 and 6. In addition, fluorescent properties of complexes 2–4 have been reported.

Two structurally diverse coordination polymers [Ce2(m-BDC)2(m-HBDC)2(MOPIP)2·3/2H2O]n (1) and [Pr2(m-BDC)3(MOPIP)2·H2O]n(2) have been synthesized by hydrothermal reaction of lanthanide chloride with mixed ligands benzene-1,3-dicarboxylic acid and 2-(4-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (MOPIP). The crystal structures of the complexes are zipper-like chains of octacoordinate Ln3+ ions, in which Ln3+ ions are bridged in different coordination modes by m-BDC2+ and decorated by MOPIP ligands. These chains are further assembled into three-dimensional supramolecular framework by π⋯π stacking and hydrogen bonding interactions. The fluorescent property and thermal stability were also investigated. Additionally, Natural bond orbital (NBO) analysis of complex 2 shows a weak covalent interaction between the coordinated atoms and Pr3+ ions.Graphical abstractHighlights► Two new lanthanide [Ln = Ce(III), Pr(III) ] polymers have been synthesized. ► The two complexes present 1D different zipper-like structure. ► The complex 2 exhibits strong photoluminescence at room temperature. ► NBO analysis shows a covalent interaction between coordinated atoms and metal ions.

Flower-like zinc oxalate with a mean diameter of 50 μm was synthesized via the reaction of zinc acetate and dimethyl oxalate in ether-water bilayer refluxing systems at low temperature. Flower-like zinc oxalate microspheres can be further transformed into the similar morphology to zinc oxide by the decomposition of zinc oxalate at 500°C. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis-differential scanning calorimetric (TG-DSC), energy dispersive X-ray spectrum (EDX) and Fourier transform-infrared spectroscopy (FT-IR) were used to characterize the structure features and chemical compositions of the as-synthesized products. The UV-Vis and photoluminescence spectrum of flower-like zinc oxide microspheres were studied. The experimental results showed that flower-like zinc oxalate microspheres may be self-assembled by the zinc oxalate flakes. The ether-water volume ratio of 4:1 and refluxing temperature of 40°C were considered to favor the preparation of flower-like zinc oxalate microspheres.

Two 3D coordination polymers, [Cd(BDC)(Medpq)·H2O]n1, and [Co(BDC)(Medpq)·H2O]n2 (BDC = terephthalic acid, Medpq = 2-Methyldipyrido[3,2-f:2′,3′-h]quinoxaline), have been synthesized by self-assembly. The structure analyses show that both of the two coordination polymers are formed by 1D infinite chains through non-covalent interactions, and both of them are based on 1D zigzag ones. The photoluminescent study of the coordination polymer [Cd(BDC)(Medpq)·H2O]n shows that it exhibit fluorescent emission bands at 567.7 nm.

Copper oxalate nanowires with a mean diameter of 100 nm and a length of 10 µm were synthesized via the reaction of copper acetate and dimethyl oxalate in ether–water bilayer refluxing system. The volume ratio of ether to water and the concentration of copper acetate were used to examine the effects on forming copper oxalate nanowires. Copper oxalate nanowires were obtained only in the case of the greater volume ratio of ether to water and the lower concentration of copper acetate. Copper oxalate nanowires with a dense structure (enclosed by a smooth surface) can be further transformed into highly porous copper oxide nanowires by the decomposition of copper oxalate nanowires at 350 °C.

•Simultaneous ATPF of sodium chlorophyllin and removal of sugars in one system.•High removal percentage of sugars by ATPF.•Demonstration of surface-activity of sodium chlorophyllin by experiment.An ethanol–tripotassium phosphate aqueous two-phase flotation (ATPF) system was first time studied for the separation of sodium chlorophyllin and sugars. The single factors influencing the recovery of sodium chlorophyllin in the top phase and removal of sugars in the bottom phase were investigated and optimized by response surface methodology (RSM). The maximum recovery percentage (88.28%) of sodium chlorophyllin were obtained at 0.55 g/mL of tripotassium phosphate, 25 mL/min of nitrogen flow rate, 26 min of flotation time and 5 mL of ethanol, meanwhile, the removal percentage of sugars reached 95.84%. Compared with aqueous two-phase extraction (ATPE), ATPF showed advantages of low consumption of organic solvent, high enrichment factors, and high separation effect. Sodium chlorophyllin were demonstrated theoretically and experimentally to have surfactivity. Finally, the scale-up experiments were conducted to further prepare sodium copper chlorophyllin, and the absorbance ratio (A406.00 nm/A631.00 nm) was 3.49. This method may blaze the trail for mass production of sodium copper chlorophyllin in industry.Download full-size image