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991.
Laibin Zhang Tingqi Ren Xiuqin Yang Liuzhu Zhou Xiaoming Li 《International journal of quantum chemistry》2013,113(19):2234-2242
The interactions between a size‐expanded Guanine analogue x‐Guanine (xG) and gold nanoclusters, Aun (n = 2, 4, 6, and 8), were studied theoretically using density functional theory. Geometries of neutral complexes were optimized using the B3LYP functional with the 6‐31+G(d,p) basis set for xG and the LANL2DZ basis set for gold clusters. The binding modes, interaction strength, and the charge‐transfer properties of different Aun‐xG complexes were investigated. Natural population analysis was performed for natural bond order charges. It was found that gold nanoclusters form stable complexes with xG and these binding results in a substantial amount of electronic charge being transferred from xG to the gold clusters. The vertical first ionization potential, electron affinity, Fermi Level, and the HOMO–LUMO gap of xG and its complexes with gold nanoclusters were also analyzed. © 2013 Wiley Periodicals, Inc. 相似文献
992.
A new and efficient access to (Z)‐N‐(2‐argio‐1‐(1H‐perimidin‐2‐yl)vinyl)benzamide derivatives from readily available substrates in HOAc is described with aid of microwave irradiation. The results of our study provide a simple, straightforward synthetic route to these interesting classes of 2‐substituted perimidines analogs in excellent yields. 相似文献
993.
Multiplex bead-array competitive immunoassay for simultaneous detection of three pesticides in vegetables 总被引:1,自引:0,他引:1
We report on a multiplex bead-based competitive immunoassay using suspension array technology for the simultaneous detection of the pesticides triazophos, carbofuran and chlorpyrifos. Three hapten-protein conjugates were covalently bound to carboxylated fluorescent microspheres to serve as probes. The amount of conjugates and antibodies were optimized. The new multi-analyte assay has dynamic ranges of 0.02–50 ng?mL?1, 0.5–500 ng?mL?1 and 1.0–1000 ng?mL?1 for triazophos, carbofuran and chlorpyrifos, respectively, and the detection limits are 0.024, 0.93 and 1.68 ng?mL?1. This new multiplex assay is superior to the traditional ELISA in possessing a wider detection range, better reproducibility and the feature of multi-target detection. Cross-reactivity studies indicated that the bead-array method is highly selective for the three target pesticides, and that individual analyses have no significant influence between each other, also without cross-reactions from other structurally related pesticides. The method was applied to analyze vegetables spiked with the three pesticides, and the recoveries were in ranges of 78.5–112.1 %, 72.2–120.2 % and 70.2–112.8 %, respectively, with mean coefficients of variation of <15 %. Figure
Schematic illustration of the multiplex bead-based competitive immunoassay 相似文献
994.
Fei-xiong Chen Li Fu Lu Feng Chuo-chuo Liu Bao-zeng Ren 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(10):1611-1614
The thermal stability and kinetics of isothermal decomposition of diosgenin were studied by thermogravimetry (TG) and Differential Scanning Calorimeter (DSC). The activation energy of the thermal decomposition process was determined from the analysis of TG curves by the methods of Flynn-Wall-Ozawa, Doyle, ?atava-?esták and Kissinger, respectively. The mechanism of thermal decomposition was determined to be Avrami-Erofeev equation (n = 1/3, n is the reaction order) with integral form G(α) = [?ln(1 ? α)]1/3 (α = 0.10–0.80). E a and logA [s?1] were determined to be 44.10 kJ mol?1 and 3.12, respectively. Moreover, the thermodynamics properties of ΔH ≠, ΔS ≠, and ΔG ≠ of this reaction were 38.18 kJ mol?1, ?199.76 J mol?1 K?1, and 164.36 kJ mol?1 in the stage of thermal decomposition. 相似文献
995.
Yiming Ren 《合成通讯》2013,43(11):1670-1676
Esterification of carboxylic acids and transesterification of β-ketoesters with alcohols have been developed using a catalytic amount of iodine in polyethylene glycol (PEG) ionic liquid (IL 1000) to afford the corresponding esters in good yields. By simple separation of the ionic-liquid phase containing the iodine, the system of I2/IL 1000 can be reused several times. 相似文献
996.
Cerium(IV) ammonium nitrate (CAN)-mediated oxidation of methylenecyclobutanes was investigated. Compared with the similar reactions of methylenecyclopropanes, the reaction products were quite different. Instead of the desired ring-enlarged product cyclopentanones, a cyclobutyl ring-intact product, spirocyclobutyl-1,2-dioxethane, was obtained. The structures of these spiroheterocycle-containing compounds are interesting, and the reactions are potentially valuable in both organic synthesis and mechanism research.
997.
An efficient and facile route for the synthesis of coumarins via the Pechmann reaction catalyzed by molecular iodine or AgOTf was described. 相似文献
998.
The reaction of (hydroxymethyl)triphenylphosphonium with benzylic or allylic halide under basic conditions at room temperature affords terminal alkenes in 61–89% yields. In this reaction, both formaldehyde and triphenylphosphine are in situ generated from (hydroxymethyl)triphenylphosphonium and further undergo Wittig olefination with benzylic or allylic halide. 相似文献
999.
Three-component reaction of aromatic aldehyde, 2-naphthalenamine, and 1,2-diphenylethanone in aqueous media catalyzed by triethylbenzylammonium chloride (TEBAC) at 90 °C gave 3-aryl-3-(naphthalen-2-ylamino)-1,2-diphenylpropan-1-one derivatives. The enol form of 1,2-diphenylethanone was tentatively proposed to participate in the formation of the products. Compared with previous methods, this three-component reaction has the advantages of green solvent, good yields, and operational simplicity. 相似文献
1000.
A novel and efficient route to H-pyrazolo[5,1-a]isoquinoline-1-carbaldehydes via a tandem reaction of N′-(2-alkynylbenzylidene)hydrazide with 2-vinyloxirane is described. The reaction proceeds through a silver(I)–rhodium(I) cooperative catalysis. 相似文献