Qingwei Wang

Syntheses, structures and photoluminescence of a series of metal-organic complexes with 1,3,5-benzenetricarboxylate and pyrazino[2,3-f][1,10]-phenanthroline ligands

A series of new metal-organic coordination complexes, [Co2(HBTC)2(Pyphen)2(H2O)4]·4H2O (1), [Mn(HBTC)(Pyphen)(H2O)] (2), [Cd2(OH)(BTC)(Pyphen)2]·H2O (3), [Cu2(OH)(BTC)(Pyphen)] (4), and [Zn2(OH)(BTC)(Pyphen)] (5) were prepared through hydrothermal reactions of pyrazino[2,3-f][1,10]-phenanthroline (Pyphen) and 1,3,5-benzenetricarboxylic acid (H3BTC) with different metal salts. All these compounds were structurally determined by X-ray single-crystal diffraction. In the dinuclear Co(II) compound (1) π–π interactions exist between Pyphen and HBTC2− ligands, resulting in interesting 2D supramolecular layers. For complex (2), the Mn(II) centers are linked by HBTC2− ligands to form a 2D (4,4) coordination layer, and these layers are interdigitated in pairs. Polymer (3) also possesses a 2D network structure composed of the tetrametallic clusters [Cd4(µ2-OH)2], which is extended to 3D arrays through the π–π interactions between Pyphen ligands. The isostructural coordination polymers (4) and (5) show the same 3D framework structure. Solid-state luminescent spectra of the Cd(II) and Zn(II) complexes indicate intense fluorescent emissions.

Syntheses and characterization of four coordination compounds derived from 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene and benzene-dicarboxylic acids

[Co2(TTBT)4(1,2-BDC)2] n u2009·u20094nH2O (1), [Pb2(TTBT)2(1,3-BDC)2] n u2009·u2009nTTBTu2009·u20092nH2O (2), [Fe(TTBT)(1,4-BDC)(H2O)] n (3), and [Zn(TTBT)(1,4-BDC)(H2O)] n (4) have been hydrothermally synthesized by self-assembly of TTBT (TTBTu2009=u200910,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), benzene-dicarboxylic acid ligands 1,2-H2BDC, 1,3-H2BDC or 1,4-H2BDC (1,2-H2BDCu2009=u20091,2-benzenedicarboxylic acid, 1,3-H2BDCu2009=u20091,3-benzenedicarboxylic acid, 1,4-H2BDCu2009=u20091,4-benzenedicarboxylic acid), and various metal salts. Compound 1 has dinuclear cluster units, four dimeric Co2 units connected to form a 32-membered ring via weak offset π–π interactions, which are further stacked via strong π–π interactions to form a 3-D supramolecular framework. Complex 2 contains 2-D layers with rhombohedral grids, which are connected to a 3-D structure by π–π interactions. 3 and 4 feature 1-D infinite chains, which are further extended by strong π–π interactions and O–H···O hydrogen bonds resulting in 3-D supramolecular architectures. The photoluminescent properties of 2 and 4 have also been investigated.

Sensitive Molecularly Imprinted Fluorescence Determination of Pyrethroids Using Green Zinc Oxide Quantum Dots

ABSTRACT Pyrethroids are similar to the natural pyrethrins produced by the flowers of pyrethrums that are effective insecticides but with potential toxicity. Here, a novel core–shell fluorescence probe for pyrethroids was prepared by precipitation polymerization. ZnO quantum dots and cyhalothrin were used as the substrate and template, respectively. Due to the formation of reversible specific recognition sites during copolymerization in the presence of acrylamide and ethyl glycol dimethacrylate, ZnO-based molecularly imprinted polymers containing cyhalothrin recognition sites were obtained. Transmission electron microscopy, infrared spectroscopy, and fluorescence spectroscopy were used to characterize the resulting ZnO-based imprinted polymers. The polymer microspheres were used to sensitively and selectively determine cyhalothrin. In addition, a linear relationship between the concentration of cyhalothrin and the fluorescence intensity was obtained from 0 to 80 µmol L−1 with a correlation coefficient of 0.9964 using the Stern–Volmer equation. The protocol was used for the determination of cyhalothrin in milk demonstrating the suitability of the methodology for practical sample analysis. The selective and sensitive fluorescence recognition, low production cost, and facile synthesis demonstrate attractive properties of ZnO-based molecularly imprinted polymers for specific molecule recognition.

Hydrothermal Synthesis and Photocatalytic Performance of Ag Quantum Dots Sensitized Bi4Ti3O12 Nanobelts

Ag/Bi4Ti3O12 heterostructure with high photocatalytic activity was synthesized via a simple and practical hydrothermal method by using Bi4Ti3O12 nanobelts as substrate materials. The as-prepared Ag/Bi4Ti3O12 heterostructure included Ag quantum dots assembling uniformly on the surface of Bi4Ti3O12 nanobelts. Comparing with pure Bi4Ti3O12 nanobelts, the composite photocatalyst exhibited enhanced photocatalytic activity under visible light irradiation in the decomposition of rhodamine B aqueous solution. The enhancement performance is believed to be induced by the intimate contact interface, where silver quantum dots serve as good electron acceptor for facilitating quick photoexcited electron transfer and thus decreasing electron-hole recombination. It was also found that the photodegradation of rhodamine B molecules is mainly attributed to the oxidation action of the generated radicals.

Quaternary heterostructured Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} composite: Synthesis and enhanced visible-light-driven photocatalytic activity

Abstract In this work, a novel quaternary heterostructured Ag–Bi 2 O 2 CO 3 /Bi 3.64 Mo 0.36 O 6.55 /Bi 2 MoO 6 composite was fabricated through a low-temperature solution-phase route. The XRD, SEM, EDX and XPS results indicated the as-prepared sample is a four-phase composite of Bi 2 O 2 CO 3 , Bi 3.64 Mo 0.36 O 6.55 , Bi 2 MoO 6 , and Ag. The photocatalytic activities of the as-synthesized samples were evaluated towards the degradation of phenol red aqueous solution. The results showed that the as-synthesized Ag–Bi 2 O 2 CO 3 /Bi 3.64 Mo 0.36 O 6.55 /Bi 2 MoO 6 photocatalysts displayed much higher photocatalytic activities in comparison with pure Bi 3.64 Mo 0.36 O 6.55 , pure Bi 2 MoO 6 , and Bi 3.64 Mo 0.36 O 6.55 /Bi 2 MoO 6 composite. Among them, the 2.5% Ag–Bi 2 O 2 CO 3 /Bi 3.64 Mo 0.36 O 6.55 /Bi 2 MoO 6 sample performed the best. The enhanced photocatalytic activity of the composite photocatalyst was attributed predominantly to the efficient separation of photoinduced electrons and holes. In addition, Ag nanoparticles were photodeposited on the surface of the composite to increase visible-light absorption via the surface plasmon resonance, which is also beneficial to the enhancement of photocatalytic performance. The possible photocatalytic mechanism of the quaternary heterostructure was also discussed in detail.

Crystal structure of (.4-oxygen)tetra(2-(4'-chlorobenzoyl) benzoato)trilead(II), Pb3O(C14H8O3Cl)4

C112H64Cl8O26Pb6, monoclinic, P21/n (no. 14), a = 11.4546(9) Å, b = 15.414(1) Å, c = 30.348(2) Å, * = 92.271(1)°, V = 5353.9 Å, Z = 2, Rgt(F) = 0.030, wRref(F ) = 0.077, T = 292 K.