Thiourea functionalized CdSe/CdS quantum dots as a fluorescent sensor for mercury ion detection

CdSe/CdS quantum dots(QDs) functionalized by thiourea(TU) were synthesized and used as a fluorescent sensor for mercury ion detection.The TU-functionalized QDs were prepared by bonding TU via electrostatic interaction to the core/shell CdSe/CdS QDs after capping with thioglycolic acid(TGA).It was observed that the fluorescence of the functionalized QDs was quenched upon the addition of Hg~(2+).The quantitative detection of Hg~(2+) with this fluorescent sensor could be conducted based on the linear relationship between the extent of quenching and the concentration of Hg~(2+) added in the range of1-300 μg L~(-1).A detection limit of 0.56 μg L~(-1) was achieved.The sensor showed superior selectivity for Hg~(2+) and was successfully applied to the determination of mercury in environmental samples with satisfactory results.     

金属酞菁化合物在TiO2表面的分散研究

Dispersion of copper(Ⅱ) phthalocyanine (CuPc), copper(Ⅱ) phthalocyaninesulfonate (CuPcS) and cobalt(Ⅱ)phthalocyaninetetrasulfonate (CoPcTS) on the surface of titanium dioxide was investigated by XRD, XPS, FT-IR and UV-Vis techniques. Results show that interaction between CuPc and TiO2 was very weak and CuPc was difficult to disperse on the surface of the support. While partly sulfurized CuPcS could be dispersed on the surface of support through sulfo-groups and its dispersion capacity was determined to be 0.085 g CuPcS/g TiO2. Completely sulfurlzed CoPcTS could also be dispersed on the surface of TiO2 as a monolayer and its dispersion capacity was 0.12 g CoPcTS/g TiO2. Interactions of the sulfo-groups as well as the electrons of CoPcTS with the surface of TiO2 could be evidenced by FT-IR characterization. Therefore, it was suggested that CoPcTS molecules be adsorbed on the surface of TiO2 in a flat-lying mode while CuPcS in a slanting one. UV-Vis spectra show that the dispersed CuPcS and CoPcTS molecules exist in both forms of monomers and dimers.     

Optical and gas sensing properties of mesoporous hollow ZnO microspheres fabricated via a solvothermal method

Mesoporous,hollow Zn O microspheres were synthesized via a hydrothermal method,using glycerol and zinc acetate as the starting materials.XRD and FESEM analysis showed that the surface morphology of the spheres with a Wurtzite structure could be reasonably adjusted by varying the weight ratio(Rw) of Zn(CH3COO)2 2H2O:H2O:C3H8O3.The responses of the gas sensor based on the spheres to 100 ppm ethanol and 100 ppm acetone are 18.9 and 10.4,respectively.The response and recovery times of the sensor to ethanol and acetone are 2 s and 3 s,3 s and 5 s,respectively.The hollow spheres show an intense UV emission at 392 nm and a broad blue-green emission at 488 nm.Interestingly,a light trapping phenomenon is revealed by UV emission and scattering measurements on the microspheres,which can be attributed to the mesoporous shell and hollow structure of the microsphere.     

Label-free Detection of Biotin Using Nanoporous TiO2/DNA Thin-film Coated Wavelength Interrogated Surface Plasmon Resonance Sensors

The sensing sensitivity of the wavelength interrogated surface plasmon resonance（WISPR） biosensor could be improved by self-assembly of nanoporous thin-film of TiO2 nanoparticles/DNA（TiO2/DNA）n（n is the number of bilayer） on wavelength interrogated surface plasmon resonance（WISPR） chips.The growth behavior and surface structure of the nanoporous thin-film were investigated by UV-Vis spectroscopy and scanning electron microscopy,respectively.The home-made WISPR sensor with Krestchmann configuration consisted of a tungsten-halogen lamp as a photon source and a CCD camera as the detector.After the deposition of （DNA/TiO2）n thin film on WISPR chips,the resonance peak of the reflection spectra appeared in air.With the increases of n,the resonance wavelength gradually red shifted,which is consistent with the simulated results.After the optimization of the porous film,the WISPR biosensor was utilized to detect low-molecular-weight analytes,such as biotin.The result demonstrates that the sensitivity of [poly（styrene sulfonate）/polyally lamine hydrochlorides]5（PSS/PAH）5 could be 4 times higher than that of polyelectrolyte multilayer modified WISPR sensor.     

Gold nanoparticles-enhanced bisphenol A electrochemical biosensor based on tyrosinase immobilized onto self-assembled monolayers-modified gold electrode

A novel electrochemical sensor based on the immobilization of tyrosinase(tyr) onto gold nanoparticles(nano-Au) and thioctic acid amide(T-NH2) self-assembled monolayers(SAMs)-modified gold electrode has been developed for the determination of bisphenol A(BPA).It was found that the nano-Au could significantly enhance the electrochemical response of tyr/nano-Au/T-NH2/Au electrode to BPA,and the enhancement effect of nano-Au on the current response was also related to the enzyme.The results indicated that the biosensor could be used as a detector for BPA determination with a linear range from3.99 ×10-7mol/L to 2.34 ×10-4mol/L and a detection limit of 1.33×10-7mol/L.In addition,this biosensor showed good reproducibility.     

Degradation of anthracene, pyrene and benzo[a]-anthracene in aqueous solution by chlorine dioxide

Polycyclic aromatic hydrocarbons (PAHs) constitute an important group of micropollutants, which are known to be mutagenic, carcinogenic and/or co-carcinogenic and relatively persistent in the environment. The effects of chlorine dioxide (ClO2) on the degradation of anthracene (ANTH), pyrene (PYR) and benzo[a]anthracene (BaA) in aqueous solution were investigated using high performance liquid chromatography (HPLC). In preliminary experiments, it was observed that ClO2 could remove these three PAHs effectively within a short time. Several factors including reaction time, the concentration of ClO2 and pH of the reaction mixture influencing the degradation ratio of PAHs have been studied by batch experiments. The results showed that the degradation ratio of PAHs was affected by reaction time and the concentration of ClO2 instead of pH. The degradation ratio of ANTH, PYR and BaA could reach their maximum as approximately 99.0%, 67.5% and 89.5%, respectively, under the condition as follows: reaction time 30, 60 and 120 min, the concentration of ClO2 0.1, 0.4 and 0.5 mmol·L-1, and pH 7.2. ANTH was selected as the representative to study the reaction mechanism with ClO2. The oxidation products formed in the reaction of ANTH with ClO2 were tentatively identified by gas chromatography-mass spectrometry (GC-MS), and the results showed that the main product was 9, 10-anthraquinone, which could be biodegraded more easily and quickly than ANTH. Through analyzing the reaction properties of ANTH and ClO2, the possible pathway for the ANTH-ClO2 reaction was proposed based on the theory of single electron transfer (SET).     

Synthesis of Novel Amphiphilic Poly （ester-amine） Dendrimers and Their Recognition of Hg2＋ at the Air／Water Interface

Two novel amphiphilic poly(ester-amine)dendrimers were synthesized and characterized by 1H NMR,13C NMR and IR spectra.Their properties of Langmuir film were investigated at the air/water interface.The relationship between the surface pressure and area isotherms of the dendrimers was found to be dependent on the nature of subphases,Interaction between HgCl2 and the dendrimers was observed,indicating that the amphiphilic dendrimers could act as a sensor for Hg^2 .     

Calix[4] crowns with Methoxynaphthoylmethyl Pendant Groups

The novel calix [4] crowns with two pendant groups were prepared by the alkylation of calix 141 crowns with 6-methoxy-2-bromoacetylnaphthalene. ^1H NMR titration and picrate extraction experiments indicated that they exhibit higher complexing efficiency than their parent compounds and possess obvious selectivity for Na^ or K^ , respetively, and that the cation is encapsulated inside the preorganized ionophoric cavity defined by carbonyl oxygens, the crown ether and the phenoxy oxygens.From UV and fluorescent spectra it is revealed that calix [4]crown-4 3a with 6-methoxy-2-naphthoylmethyl pedant groups exhibits remarkable cation-induced photophysical effects and it could be utilized as a selective fluorescent sensor for Ca^2 .     

Low-bandgap polymers with quinoid unit as π bridge for high-performance solar cells

To construct efficient low band gap polymers, increasing the Quinone structure of the polymer backbone could be one desirable strategy. In this work, two D–Q–A–Q polymers P1 and P2 were designed and synthesized with thiophenopyrrole diketone(TPD) and benzothiadiazole(BT) unit as the core and ester linked thieno[3,4-b]thiophene(TT) segment as π-bridging, and the main focus is to make a comparative analysis of different cores in the influence of the optical, electrochemical, photochemical and morphological properties. Compared with the reported PBDTT_(EH–)TBTT_(HD-i), P1 exhibited the decreased HOMO energy level of-5.38 e V and lower bandgap of 1.48 e V. Furthermore, when replaced with BT core, P2 showed a red-shifted absorption profile of polymer but with up-shifted HOMO energy level. When fabricated the photovoltaic devices in conventional structure, just as expected, the introduction of ester substituent made an obvious increase of V_(OC) from 0.63 to 0.74 V for P1. Besides, due to the deep HOMO energy level,higher hole mobility and excellent phase separation with PC_(71) BM, a superior photovoltaic performance(PCE = 7.13%) was obtained with a short-circuit current density(J_(SC)) of 14.9 m A/cm~2, significantly higher than that of P2(PCE = 2.23%). Generally, this study highlights that the strategy of inserting quinoid moieties into D–A polymers could be optional in LBG-polymers design and presents the importance and comparison of potentially competent core groups.     

Polyethylene Glycol as Support and Phase Transfer Catalyst in Aqueous Palladium-catalyzed Liquid-phase Synthesis

Recently, the liquid-phase synthesis of small organic compounds has been a preferable strategy due to its combination with the advantage of solution-phase and solid-phase methods1. Among the various soluble polymers, polyethylene glycol (PEG) is the most useful as support. It has been reported that PEG bound substrates could also play the role of phase-transfer catalyst (PTC) in some reactions2. Herein we reported that palladium-catalyzed coupling reactions could be taken place smoothly…     

Preparation of Pt／C Catalyst with a New and Simple Organic Sol Method

It is reported for the first time that the Pt/C catalyst can be prepared with a new and simple organic sol method using SnCl2 as the reductant. It was found that the average size of the Pt particles in the Pt/C catalysts could be controlled with controlling the preparation conditions. The effect of the average sizes of the Pt particles in the Pt/C catalysts obtained with this method on the electrocatalytical activity of the oxidation of methanol was investigated.     

MOF-derived Cu_2O/Cu NPs on N-doped Porous Carbon as a Multifunctional Sensor for Mercury(Ⅱ) and Glucose with Wide Detection Range

Cu_2O/Cu nanoparticles(NPs) in the nanoporous carbon matrix(designated as Cu_2O/Cu@NPC) has been synthesized by in-situ calcination of a cupper-based metal-organic framework(Cu-MOF), and its morphology and composition were characterized by PXRD, SEM and Raman. Furthermore, elemental mapping and XPS analysis not only show Cu NPs is generated along with nitrogen(N)-doped carbon, but also indicate Cu_2O NPs locates in the external layer of Cu@NPC. In addition, the adsorption of dye studies implies that Cu_2O/Cu@NPC exhibits obvious interaction with Rhodamine B(Rh B) due to the feature of porous and N-doped structure. Cu_2O/Cu@NPC has highly electrocatalytic performance for glucose and mercury(Ⅱ) with wide detection range and good stability, which can be used as a novel multifunctional sensor for glucose and mercury(Ⅱ).     

Improved Performance of W／HZSM-5 Catalysts for Dehydroaromatization of Methane

The dehydroaramatization of methane over W-supported ZSM-5 with varying degrees of Li^ ion-exchanged catalysts was studied with and without oxygen at 1073 K and atmospheric pressure.Catalyst activity and stability were found to be influenced by the catalyst acidity related to BrSnsted acid sites and by the presence of oxygen in the feed. The NH3-TPD and FTIR-pyridine results demonstrated that partially exchanged of H^ ions by Li^ into the W/HZSM-5 catalysts could be used to control the amount of strong acid sites on the catalyst surface. Without oxygen, the 3WHLi-Z (5:1) catalyst that has strong acid sites equal to nearly 74% of the original strong acid sites in the parent HZSM-5 exhibited the highest methane conversion and selectivity towards aromatics. However, the catalyst deactivated in a five hour period. In the presence of oxygen, the catalyst activity and stability could be improved further.The results of this study revealed that a suitable amount of strong Bronsted acid sites as well as oxygen addition in the feed increased the catalyst activity and stability. The 3WHLi-Z(5:1) catalyst exhibited improved performance in the dehydroaromatization of methane.     

Syntheses of 10-Hydroxy-5,10-dihydrophenophosphazine 10-Oxide and Its Methyl Derivatives

Ph2NH and PCl3 interacted at a molar ratio of 1:1.05 and slow-elevated temperature and then at 210-220 ℃ for 6h.The brown solution obtained was treated with H2O to produce a very hard brown solid believed to be a mixture of 5,10-dihydrophenophosphazine 10-oxide(1a) and 10,10′(5H,5H′）-spirobipenophosphazinium chloride(1b).This brown solid was directly oxidized with peracetic acid in HOAc prior to the separation of them to give compound 10-hydroxy-5,10-dihydropheno-phosphazine 10-oxide(2) with a higher yield(45%) than that of the literature(27%).When treated with excess SOCl2.compound 2 could quantitatively be converted to the corresponding phosphinyl chloride and the latter could further be transformed into 10-methoxy-5,10-dihydrophenophosphazine 10-oxide in 70% as treated with NaOMe in methanol.Compound 2 could also be converted to a bisanion when treated with NaH in DMF.The resulted bisanion reacted with MeI to give 5-methyl-10-hydroxy-5,10-dihydrophenophosphzine 10-oxide in a 73% yield which would be converted to 5-methyl-10-methoxy-5,10-dihydrophenophosphazine 10-oxide.All these compounds obtained were identified by surveying their melting points.and spectra and elemental analysis.     

Water-soluble Porphyrin as Temperature Sensor Based on Fluorescent Enhancement

A novel water-soluble porphyrin[5,10,15,20-tetra（3-ethoxy-4-hydroxy-5-sulfonate）phenyl porphyrin, H2TEHPPS] was designed and synthesized, which could be used as a potential fluorescence sensor to detect temperature changes. The studies were performed in solution phase and the concentration of H2TEHPPS was 2.0×10^-5 mol/L. The optical properties of H2TEHPPS were investigated based on the UV and fluorescence spectra. The results show that the fluorescence intensity of H2TEHPPS is directly proportional to temperature in the range of 293-353 K So H,TEHPPS can be used as a molecular temoerature sensor in biomedical and other fields.     

Selective catalytic oxidation of NO with O2 over Ce-doped MnOx/TiO2 catalysts

A series of Ce-doped MnOx/TiO2 catalysts were prepared by impregnation method and used for catalytic oxidation of NO in the presence of excess O2. The sample with the Ce doping concentration of Ce/Mn=1/3 and calcined at 300°C shows a superior activity for NO oxidation to NO2. On Ce(1)Mn(3)Ti catalyst, 58% NO conversion was obtained at 200°C and 85% NO conversion at 250°C with a GHSV of 41000 h-1, which was much higher than that over MnOx/TiO2 catalyst (48% at 250°C). Characterization results implied that the higher activity of Ce(1)Mn(3)Ti could be attributed to the enrichment of well-dispersed MnOx on the surface and the abundance of Mn3+ and Ti3+ species. The addition of Ce into MnOx/TiO2 could improve oxygen storage capacity and facilitate oxygen mobility of the catalyst as shown by PL and ESR, so that its activity for NO oxidation could be enhanced. The effect of H2O and SO2 on the catalyst activity was also investigated.     

COORDINATION POLYMERIZATION OF BENZOTRIAZOLE ON THE SURFACE OF METALLIC COPPER

The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild conditions to form bis (benzotriazolato) copper (Ⅱ) and benzotriazolato copper (Ⅰ)which covered the surface of copper metal in the shape of polymeric materials. Since benzotriazole is of great interest as a ligand in that its presence in many biological system with metal ions, and is considered as a corrosion inhibitor, this work will be in favour of the study of protective corrosion.     

π-π Stacking,Hydrogen Bonding and Magnetic Coupling Mechanism on a Mono-nuclear Cu~Ⅱ Complex

A new mono-nuclear CuII complex [Cu(DPP)(DP)Br](ClO4)H2O (DPP = 2-(3,5- dimethyl-1H-pyrazol-1-yl)-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole) has been syn- thesized with 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1,10-phenanthroline and 3,5-dimethyl-1H-pyrazole as ligands, and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic system, space group P21/c with a = 13.765(2), b = 17.044(3), c = 10.9044(16), β= 97.112(2)°, V = 2538.5(6)3, Z = 4, C22H24BrClCuN6O5, Mr = 631.37, Dc = 1.652 g/cm3, F(000) = 1276 and μ= 2.585 mm-1. In the crystal, DPP functions as a tridentate ligand and CuII ions assume a distorted square pyramidal geometry with Br atom lying on the apex, and at the same time, there is π-π stacking between adjacent complexes, which deals with two 1,10-phenanthroline plane rings. In addition to the π-π stacking, there are C-H···Br non-classic hydrogen bonds between adjacent complexes. The theoretical calculations reveal that the π-π stacking and C-H···Br non-classic hydrogen bond result in a weak anti-ferromagnetic interaction with 2J = -5.34 cm-1 and a weak ferromagnetic 2J = 5.92 cm-1, respectively. The magnetic coupling sign from the π-π stacking could be explained with McConnell I spin-polarization mechanism.     

PHOTOINITIATED INVERSE EMULSION POLYMERIZATION OF SODIUM ACRYLATE

Photoinitiated inverse emulsion polymerization of sodium acrylate (AANa) in kerosene was carded out at room or lower temperature, using 2,2-dimethoxy-2-phenylacetophenone (DMPA) as the initiator. Kinetic investigations indicated that the polymerization could be completed in about 30 min and produce polymer with high molecular weight (10^6-10^7). It was found that monomer droplets are the main sites for the polymerization (nucleation). With the increase of DMPA concentration, polymerization rate (Rp) reaches a maximum value while molecular weight of the produced polymer has an adverse result, but the dependence of Rp on incident light intensity is similar. Influences of other parameters such as monomer concentration, emulsifier content and reaction temperature, etc. were also studied. At lower pH values of water phase, Rp depends strongly on the pH due to the electrostatic interaction between the ionized radicals and the monomer. At higher pH, Rp shows a slight dependence on pH.     

EFFECT OF CHRONIC IRRADIATION OF ~(60)Co-γ-RAY AT LOW DOSE RATE ON RHESUS MONKEY——EFFECT ON PERIPHERAL BLOOD AND TESTIS

The authors have demonstrated that after a long-term chronic irradiation of 2.17 rad/day for 2 months, the testis of the experimental monkey (Macaca mulatta) is extremelyatrophied with a loss of reproductive ability. But the effect on peripheral blood is notapparent even after irradiation for 57 months. It shou1d be noted that rhesus monkeys, being as sensitive to irradiation and similar inevolutionary steps as human beings, could be used as experimental animals to further studythe dose rate for aspermatogenesis, the morphological injuring effect on the reproductivesystem and the cytogenetic effect of irradiation, and this is highly important to working outa standard of promised dose of irradiation for X-ray workers and an index of radiationprotection monitoring.