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1.
A hyperbranched poly(aryleneethynylene) containing anthracene chromophore was synthesized by palladiumcatalyzed cross-coupling reaction of 2,4,6-triiodophenyl 9-anthracenylcarboxylate with 9,9-bis[4-(2-propynyloxy)phenyl]- 9H-fluorene. The structure and properties of the polymer are characterized and evaluated by NMR, IR, UV, PL and TGA analyses. The polymer is soluble in common organic solvents, possesses high thermal stability (Td 〉 330℃), and emits a strong blue light of 465 nm in both solution and solid states.  相似文献   

2.
A terpyridine derivative DPTP [di-(4-methylphenyl)-2,2':6',2"-terpyridine] was conveniently synthesized from 2-bromopyridine via halogen-dance reaction, Kharash coupling and Stille coupling reaction. Then its corresponding ruthenium complex Ru-DPTP [N,N,N-4,4''-di-(4-methy,phenyl)-2,2':6',2"-terpyridine-N,N,N-tris(is,-thi,cyanat,)- ruthenium(H) ammonium] was obtained and fully characterized by IR, UV-Vis, ESI MS and elemental analysis. The MLCT absorption band of Ru-DPTP was blue-shifted from 570 to 500 nm upon addition of Hg^2+. Among a series of surveyed metal ions, the complex showed a unique recognition to Hg^2+, indicating that it can be used as a selective colorimetric sensor for Hg^2+.  相似文献   

3.
The kinetics of the oxidation of lactic acid(Lac) by dihydroxyditelluratoargentate(Ⅲ)[abbreviated as DDA of Ag(Ⅲ)]anions was studied in an aqueous alkaline medium by conventional spectrophotometry in a temperature range of 25-40℃.The order of the redox reaction of lactic acid and DDA was found to be first-order.The rates increased with the increase in [OH^-]and decreased with the increase in [tellurate].No free radical was detected.In the view of this the dihydroxymonotelluratoargentate(Ⅲ)species(DMA) is assumed to be the active species.A plausible mechanism involving a two-electron transfer is proposed,and the rate equation derived from the mechanism can be used to explain all the experimenttal results.The activation parameters(25℃)and the rate constants of the rate-determining step along with the preequilibrium constants at different temperatures were evaluated.  相似文献   

4.
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.  相似文献   

5.
Photochemical oxidation of thiophene in n-octane/water extraction system using O2 as oxidant was studied. The reaction mechanism ofthiophene oxidation was proposed. Results obtained here can be used as the reference for the oxidative desulfurization of gasoline because thiophene is one of the main components containing sulfur in fluid catalytic cracking gasoline. Thiophene dissolved in n-octane was photodecomposed and removed into the water phase at ambient temperature and atmospheric pressure. A 500 W high-pressure mercury lamp (main wave length 365 nm, 0.22 kW/m) was used as light source for irradiation, and air was introduced by a gas pump to supply O2. Thiophene can be photo-oxidized to sulfone, oxalic acid, SO4^2-, and CO2. The desulfurization yield of thiophene in n-octane is 58.9% under photo-irradiation for 5 h under the conditions of air flow at 150 mL/min and V(water):V(n-octane)=1:1. It can be improved to 92.3% by adding 0.15 g zeoliteartificial into 100 mL reaction system, which is the adsorbent for O2 and thiophene. And under such conditions, the photo-oxidation kinetics of thiophene with O2/zeoliteartificial is first-order with an apparent rate constant of 0.5047 h^-1 and a half-time of 1.37 h. The sulfur content can be depressed from 800 μL/L to less than 62 μL/L.  相似文献   

6.
A superoxide dismutase( SOD ) was purified to homogeneity from fresh camellia pollen by means of ammonium sulfate precipitation and column chromatography with DEAE-cellulose( DE52 ), Sephadex G-100 and phenyl sepharose^TM 6 Fast Flow columns. Its specific activity could reach to 4034 U/mg protein and it was determined to be Cu/ Zn-SOD according to its different sensitivities to different inhibitors. The molecular weight of the SOD and its subunit were 69500 and 34700, respectively, based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS- PAGE), which implicates that the SOD in camellia pollen is a dimmer composed of two identical subunits. The isoelectric point of the enzyme was determined to be 4. 1 by isoelectric focusing electrophoresis and the N-terminal amino acid was identified to be Gly by the DNS-Cl method. Its α-Helix was also calculated to be approximately 21.8% according to the circular dichroism(CD) spectra.  相似文献   

7.
Catalysts based on Co(II) supported on active carbon were prepared and loaded in static bed. The hydroquinone would be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(II)/active carbon catalyst. After activate treatment, the active carbon was immerged in cobaltous nitrate solution, then put into a drying oven, Co(II) could be loaded on the micro-surface of carbon. Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(II) was used to reduce activation energy of hydroquinone. Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard. Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(II). The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40 ℃, pH 5 and reaction time 2.5h.  相似文献   

8.
Carbosilane dendrimers with p-bromophenyl core were synthesized by alternating Grignard and hydrosilylation reaction. And the α-naphthalenyl was connected to the core by the Suzuki coupling reaction. A new carbosilane dendrimer with big π-conjugated structure [4-(naphthalen-l-yl)phenyl core] was given. It shows Suzuki coupling reaction is an effective and powerful core-functionalization method and the satisfactory result can be obtained through prolonging the reaction time with the increase of the generation of dendrimer.  相似文献   

9.
刘习奎 《高分子科学》2014,32(8):1052-1059
A green approach to the synthesis and morphological control of high performance polyimides and their nanohybrid shish-kebabs in glycerol through reaction-induced crystallization of nylon-salt-type monomers was reported. Crystalline polyimide nanoplates can be observed by direct polycondensation of pyromellitic acid with various kinds of aliphatic or aromatic diamines. With the existence of carbon nanotuhes, the polyimides can be successfully decorated on the surface of CNTs through a reaction-induced hetero-epitaxial crystallization process, and resulted in novel polyimide/CNT nanohybrid shish-kebabs (NHSKs) structures. The morphologies of the NHSKs can be fine-tuned through changing the concentration of monomers or the reaction temperature, especially through the introduction of dynamic imine chemistry, the formation process of NHSKs can be attributed to a soft epitaxy mechanism. Thus a green approach for the synthesis of high performance polyimides and their CNT based nanohybrid structures was explored, which should be of great value for their applications in high performance reinforced nanocomposites.  相似文献   

10.
Catalytic performance of W/HZSM-5 in selective catalytic reduction of NO by acetylene was investigated in a reaction system with 1600 ppm of NO, 800 ppm of C2H2, and 9.95% of O2 in He. It was found that promotional effect of tungsten on the reaction is strongly affected by catalyst preparation conditions and Si/Al ratio of the parent zeolite. A better dispersion of tungsten on HZSM-5 and relatively more monomeric tungsten species were found on 8%W/HZSM-5 prepared by impregnation of the zeolite with lower SiO2/A1203 ratio (25) in ammonic ammonium tungstate solution and calcination of the resulting material at higher temperature (550 ℃). The highest NO conversion to N2 of 86.3% in the reaction system was obtained at 350 ℃ over the catalyst thus prepared. The mechanism of monomeric tungsten species improving the C2H2-SCR can be attributed to accelerating the formation of active nitrate species.  相似文献   

11.
Fumed silica/bisphenol A dicyanate ester(BADCy)nanocomposites were prepared by introducing different contents of nano-sized fumed SiO2 into the BADCy matrix.Two different average primary particle diameters of 12 and 40 nm were chosen.Dibutyltindilaurate(DBTDL)catalyst was chosen to catalyze the cyanate ester group into triazine group via cyclotrimerization reaction.The SEM micrographs indicated that the fumed SiO2 particles were homogeneously dispersed in the poly(bisphenol A dicyanate)matrix by means of ultrasonic treatment and the addition of a coupling agent. The FTIR spectroscopy shows that,not only DBTDL catalyzes the polymerization reaction but also-OH groups of the SiO2 particles surface help the catalyst for the complete polymerization of BADCy monomer.The thermal stability of the cured BADCy can be improved by adequate addition of fumed SiO2.A slight increase in the dielectric constant and dielectric loss values were identified by testing the dielectric properties of the prepared nanocomposite samples.By increasing the SiO2 content,there was a slight increasing in the thermal conductivity values of the tested samples.The obtained results proved that the fumed silica/BADCy nanocomposites had good thermal and dielectrical properties and can be used in many applications such as in the thermal insulation field.  相似文献   

12.
The thermal decomposition of Zn-MPA complex was investigated under microwave irradiation. ZnO and ZnS nanocrystals could be obtained by decomposing Zn-MPA(3-mercaptopropionic acid) complex under different reaction conditions. It was found that both the pH value of the solution and the molar ratio of Zn2+ and MPA can play an important role in the formation of ZnO and ZnS nanocrystals. MPA mainly acts as an S source or as a complexing agent. This study provides a new route for the controllable preparation of semiconductor nanocrystals.  相似文献   

13.
The kinetics of oxidation of ethylene glycol and 1,3-butylene glycol by dihydroxydiperiodatoargentate(Ⅲ) in alkaline medium have been studied by spectrophotometry in the range of 298.2-318.2 K. It is shown that the reaction was first order with respect to each reductant and Ag(Ⅲ), and kobs increased with an increase of [OH^-]. A plausible mechanism of reaction involving a pre-equilibrium of adduct formation between complex and reductants was proposed, which could be applied to explain all experimental phenomena, and the activation parameters of the ratedetermining step have been also calculated.  相似文献   

14.
A new mononuclear Cu(Ⅱ) dithiocarbamate complex CuI(prdtc)(phen) 1 (prdtc = N-pyrrolidinyldithiocarbamate, phen = 1,10-phenanthroline) was synthesized and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 8.7110(9), b = 14.7143(14), c = 14.8507(15) A, β = 109.721(6)°, V = 1791.9(3) A3, Z = 4, Dc = 1.916 g/cm3, CI7H16CulN3S2, Mr = 516.89, λ(MoKa) = 0.71073A,μ = 3.178 mm^-1, F(000) = 1012, the final R = 0.0369 and wR = 0.0987. A total of 4082 unique reflections were collected, of which 2916 with I 〉 2σ(I) were observed. The Cu(Ⅱ) atom is five-coordinated in a distorted square-pyramidal geometry by one I atom in the apical position, two S atoms from a prdtc ligand and two N atoms from a phen ligand in the basal plane. There exist face-to-face aromatic π-π stacking interactions between adjacent phen ligands stabilizing the structure and making the complex assemble into a 1D structure along the a axis. It can be concluded that the difference of the dtc flexibility and reaction conditions result in the structural difference between complex 1 and CuI(dmdtc)(phen) (dmdtc = N, N-dimethyldithiocarbamate).  相似文献   

15.
A novel chromogenic reaction involving copper(Ⅱ) and bromosulphonazo Ⅲ (Br-SAZⅢ) in hexamethylenetetramine- hydrochloric buffer solution was investigated. The results showed that a blue complex of copper(Ⅱ) and bromosulphonazo Ⅲ was formed with a molar ratio of 1:1. The apparent molar absorptivity was 3.3×10^5Lmol-1cm-1 and the maximum absorption peak was at 616.8 nm. The proposed procedure was used for quantitative estimation of Cu(II) in the concentration range of 0-1.024μg/mL with the detection limit (3σ) of 7.03 × 10^-4 μg/mL (n = 20). The relative standard deviations (RSDs) were 0.56-4.68%. Under the optimized conditions, total copper in the vegetables and tea was successfully determined. 2007 Li Yuan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.  相似文献   

16.
A selenium-functionalizedε-caprolactone was synthesized by introducing a phenyl selenide group at the 7-position.A polymer was obtained through the ring-opening polymerization of this monomer in a base/thiourea binary organocatalytic system.A living polymerization process was achieved under mild conditions.The resulting polymers had a controlled molecular weight with a narrow molecular weight distributions and high end-group fidelity.Random copolymers could be obtained by copolymerizing this monomer withε-caprolactone.The thermal degradation temperature of the obtained copolymers decreased with the increasing molar ratio of selenide functionalized monomer in copolymers,while the glass transition temperature increased.In addition,the phenyl selenide side group could be further modified to a polyselenonium salt,which resulted in a polymer with good antibacterial properties.The survival rate of E.coli and S.aureus was only 9%with a polymer concentration of 62.5μg/mL.  相似文献   

17.
A phosphrous-containing poly(aryl ether ketone)was synthesized derived from bisphenol-A and bis[4-(4- fluorobenzoyl)phenyl] phenyl phosphine oxide(FPPPO)by nucleophilic substitution reaction.The structure of the polymer was characterized by FT-IR,~1H-NMR and ~(31)p-NMR.The thermal property of the PAEK was measured by DSC and TGA. The glass transition temperature(T_g)of the polymer was 205℃,and the 5% weight loss temperature under nitrogen was 475℃.Good solubility of the polymer in organic solvents,such as N-methylpyrrolidone,dimethylformamide, dimethylacetamide,dimethylsulfoxide and chloroalkanes was observed,flexible film was obtained from the polymer's CH_2Cl_2 solution.The limiting oxygen index(LOI)of the PAEK was 40,which indicated that organic phosphorus moiety can offer good flame retardant property to the polymer.  相似文献   

18.
A new method for the preparation of SBA-15-supported palladium catalyst for Heck reaction in supercritical carbon dioxide was presented.The newly formed SBA-15-supported palladium catalyst(Ph-SBA-15-PPh3-Pd) exhibited high catalytic activity for the Heck reaction of 4-nitrobromobenzene with methyl acrylate.The catalyst can be reused several times without a loss of activity.  相似文献   

19.
The catalytic activity of VO(acac)2 for the cyclohexane(Cy) oxidation was studied. The effects of various parameters, such as the amounts of H202, HNO3, H20 and Cy were investigated. The highest total turnover num- ber(TON) is 234, which can be increased to 353, 342 and 403, respectively with the adding of o-phthalic, m-phthalic or p-phthalic acid. A reaction mechanism was also supposed primarily.  相似文献   

20.
孙杨  唐宁 《中国化学》2007,25(5):674-678
A series of chiral salen-Mn(Ⅲ) complexes featuring two tertiary amine units were synthesized and employed in the enantioselective epoxidation of unfunctionalized alkenes in the presence of pyridine N-oxide and 2,6-dimethylpyridine N-oxide as proximal ligands, respectively. Moderate to high enantioselectivity and acceptable yields were achieved when NaClO was used as terminal oxidant under CH2Cl2/H2O biphasic media. Methyl iodide was found to be an effective additive to accelerate the epoxidation, possibly owing to the formation of quaternary ammonium units on catalysts, which may facilitate the reaction in an oil/water biphasic medium. The subsequent stimulation experiment was carried out, and the resulting ESI-HRMS analysis revealed the formation of a novel (salen)manganese(m) intermediate featuring two quaternary ammonium units, and bearing a pyridine N-oxide and a molecule of water simultaneously axially-coordinated backbone.  相似文献   

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