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991.
A direct, concise, synthetic method for the generation of [1,2,3]triazolo[5,1-a]isoquinoline derivatives, using a selective cascade cyclization of unsymmetrical substituted 1,2-bis(phenylethynyl)benzene derivatives with NaN3, has been developed. The reaction gave different substituted [1,2,3]triazolo[5,1-a]isoquinolines in moderate to good yields. It was found that the substituents on the alkynes were important for the selectivities of the cascade cyclization sequences. 相似文献
992.
Shu‐Xian Hu Jian‐Guo Yu Eddy Y. Zeng 《International journal of quantum chemistry》2013,113(8):1128-1136
Calculations using density functional theory were performed to explore the mechanisms for atmospheric degradation of isopropyl methyl methylphosphonate (IMMP). The potential energy surface profiles for OH‐initiated reaction of IMMP were constructed, and all possible degradation channels were considered. Rate constants were further calculated using transition state theory. It was established from these calculations that H‐abstractions from alkyl groups have much lower energy barriers than substitutions of alkoxyl groups, and four possible H‐abstraction channels are competitive. Investigations into the secondary reactions under the presence of O2/NO were also performed. It is shown that O2 addition, reaction of peroxide radicals with NO to form RO radicals, and removal of ·RO are the major degradation pathways for alkyl radicals. Four selected products, CH3OP(O)(CH3)OC(O)CH3, CH3OP(O)(O)CH3, (CH3)2CHOP(O)(CH3)OH, and (CH3)2CHOP(O)(CH3)OCH?O, are predicted to be the major products in this study. © 2013 Wiley Periodicals, Inc. 相似文献
993.
A series of new dispiropyrrolidine derivatives were synthesized via the three‐component 1,3‐dipolar cycloaddition reaction of azomethine ylides generated in situ by the decarboxylative condensation of acenaphthenequinone and sarcosine or l ‐thioproline with 5‐benzylidene‐1,3‐dimethylpyrimidine‐2,4,6‐trione. The structures of the products were identified by IR, 1H‐NMR, and HRMS spectra. 相似文献
994.
Shanshan Zhu Ning Gan Daodong Pan Yi Li Ting Yang Futao Hu Yuting Cao Dazhen Wu 《Mikrochimica acta》2013,180(7-8):545-553
We have prepared core-shell magnetic molecularly imprinted polymer nanoparticles for recognition and extraction of tributyl tin (TBT). The use of particles strongly improves the imprinting effect and leads to fast adsorption kinetics and high adsorption capacities. The functional monomer acrylamide was grafted to the surface of Fe3O4 nanospheres in two steps, and MIP layers were then formed on the surface by creating a MIP layer on the surface consisting of poly(ethyleneglycol dimethacrylate) with a TBT template. The particles were characterized in terms of morphological, magnetic, adsorption, and recognition properties. We then have developed a method for the extraction of TBT from spiked mussel (Mytilidae), and its determination by liquid chromatography-tandem mass spectrometry. The method has a limit of detection of 1.0 ng?g?1 (n?=?5) of TBT, with a linear response between 5.0 and 1,000 ng?g?1. The proposed method was successfully applied to the determination of trace TBT in marine food samples with recoveries in the range of 78.3–95.6 %. Figure
The preparation procedures of core-shell magnetic molecularly imprinted polymer nanoparticles for recognition and extraction of tributyl tin (TBT) in seafood 相似文献
995.
We are reviewing the state of electrochemical sensing of H2O2 based on the use of metal nanoparticles. The article is divided into subsections on sensors based on nanoparticles made from Ag, Pt, Pd, Cu, bimetallic nanoparticles and other metals. Some sensors display high sensitivity, fast response, and good stability. The review is subdivided into sections on sensors based on heme proteins and on nonenzymatic sensors. We also discussed the challenges of nanoscaled sensors and their future aspects. Figure
Sensing mechanism of (A) mediator-based enzyme biosensor, (B) mediator-less enzyme biosensor and (C) nonenzymatic sensors with metal nanoparticles for the electrocatalytic reduction toward H2O2 相似文献
996.
DNAzyme based electrochemical sensors for trace uranium 总被引:1,自引:0,他引:1
Qiong Tang Yali Yuan Xilin Xiao Ping Guo Jianbang Hu Dandan Ma Yangyang Gao 《Mikrochimica acta》2013,180(11-12):1059-1064
We have developed a uranyl-specific DNAzyme that was immobilized on the surface of a gold electrode to give a highly sensitive and selective biosensor for uranyl ion. The typical DNAzyme system consisted of the RNA (rA) as the substrate (ADNA), and the other strand is the enzyme (TDNA) with a ferrocene (Fc). The presence of uranyl ion induces the cleavage of the DNA substrate strand at the rA position to form two fragments. The Fc unit thereby is released from the surface of the electrode, and this results in a decreased peak current. This electrochemical biosensor has a dynamic range from 2 nM to 14 nM of uranyl ion, with a detection limit at 1 nM. It exhibits high sensitivity and excellent selectivity over other metal ions, and thus represents a promising technique for simple, fast, on-site, and real-time electrochemical sensing of UO2(II) ion. It also serves as a guide in choosing different methods for designing electrochemical sensors for other metal ions. Figure
We have developed a uranyl-specific DNAzyme that was immobilized on the surface of a gold electrode to give a highly sensitive and selective biosensor for uranyl ion. The typical DNAzyme system consisted of the RNA as the substrate and the other strand is the enzyme with a ferrocene (Fc). This electrochemical biosensor exhibits high sensitivity and excellent selectivity, and represents a promising technique for simple, fast, on-site, and real-time electrochemical sensing of UO2(II) ion. 相似文献
997.
Optically active 1, 2-Diphenylethylendiamine(9) is obtained by asymmetric oxidative coupling reaction of d-camphor ketimine anion (4). Among various oxidating agents, TiCl(Oipr)3 is better than l2, Br2, CuCl2, FeCl3 and BrCH2CH2Br. 相似文献
998.
Aluminium powder has been used to reduce titanium tetrachloride to generate the low valent titanium (LVT)reagent which can induce the reductive coupling of aldehydes and ketones to form the corresponding pinacols or olefins. However, arylsulfonyl chlorides will give diaryldisulfides under the same condition. 相似文献
999.
A series of heterometallic LnIII–SbIII edta‐containing compounds with the formulas [Sb2(edta)2Ln]NO3 · nH2O [edta = ethylenediaminetetraacetate; Ln = Eu, n = 7 ( 1 ); Gd, n = 7.5 ( 2 ) and Tb, n = 8 ( 3 )] were synthesized and characterized by elemental analyses (EA), powder X‐ray diffraction (PXDP), Fourier transform infrared spectroscopy (FT‐IR), and thermogravimetric analyses (TGA). Their fluorescence and magnetic properties were also studied. The thermal analysis demonstrates the compounds formation of the antimony, lanthanide ions, and edta4– ligands. FT‐IR spectra reveal that the antimony and lanthanide ions are connected through the carboxylate bridges. The studies of luminescence properties show that compounds 1 and 3 exhibit typical luminescence in the visible region. Furthermore, magnetic properties reveal compounds 2 and 3 have weak ferromagnetic behavior. 相似文献
1000.
Ya Gao Nan Chen Weiwu Hu Chuanping Feng Baogang Zhang Qian Ning Bin Xu 《Journal of solution chemistry》2013,42(4):691-704
Adsorption is an effective treatment process for removing phosphorus and thus controlling eutrophication. In this study, a clay composite material called Al–dolomite–montmorillonite (Al–DM) was prepared and characterized. Al–DM performed well with respect to phosphate removal, with its performance depending on the Al–DM loading, contact time, initial phosphorus concentration and initial solution pH. Adsorption mechanisms were investigated by conducting batch tests on phosphate adsorption using the Al–DM. The adsorption process fitted both the pseudo-second-order kinetics model and the intra-particle diffusion model. The Langmuir, Freundlich and BET models all adequately described the adsorption isotherm data. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous in nature. Al–DM is an effective adsorbent for phosphate removal mainly due to its hierarchical porous structures as shown by characterization with SEM and EDS. Chemical changes occurring before and after adsorption in a water environment indicated that Al–DM had little negative effect on water quality. 相似文献