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131.
DFT study the interaction of β‐cyclodextrin with benzyl azide and phenyl acetylene in synthesis of 1,2,3‐triazoles
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The phenyl acetylene and benzyl azide cycloaddition reaction in water in the presence of β‐cyclodextrin (β‐CD) as a phase transfer catalyst (PTC) can get a better yield in a shorter time. The interaction between β‐CD and phenyl acetylene or benzyl azide plays an important role in this reaction. This paper studies the complexes of β‐CD with phenyl acetylene and benzyl azide using density functional theory (DFT) method. In order to find out the orientations of guests in the cavity of β‐CD, binding energy and deformation energy are investigated, and the calculated results are confirmed by 1H nuclear magnetic resonance (1HNMR). The data from single point energy indicate that the inclusion complexes can improve the solubilities of phenyl acetylene and benzyl azide in water. The 13C and 15N spectra show that the most obvious variation concentrates on C6 and C8 of phenyl acetylene and N15 of benzyl azide in complexes. Mulliken charge and frontier orbital are employed for revealing the charge distribution. The effect of β‐CD is discussed in terms of the calculated parameters. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
132.
Piao He Jian‐Guo Zhang Li‐Na Feng Kun Wang Tong‐Lai Zhang Shao‐Wen Zhang 《Journal of Physical Organic Chemistry》2015,28(6):423-427
1,5‐Daminotetrazole (DAT) is of much interest because of the practical significance and the diversity of characteristics. The study on the decomposition pathway and the kinetics of DAT has been performed based on the quantum chemistry theory. The minimum energy path (MEP) calculation has shown that NH2N3 and NH2CN are the initially detected products of DAT. And the structures of reactant, products and transition state were optimized with MP2 methods using 6‐311G** basis sets, and the energies were refined using CCSD(T)/6‐311G** levels of theory. The calculated rate constants were obtained using the conventional transition‐state theory (TST) and the canonical variational transition‐state theory (CVT) methods. The calculation results indicated that the energy barrier of decomposition reaction is 47.98 kcal mol?1 and the variational effect is small. In addition, the rate constants and the Arrhenius experience formula of DAT decomposition have been obtained between 200 and 2500 K temperature regions. The fitted three‐parameter expressions calculated using the TST and CVT methods are (TST) and (CVT). This work may provide the theoretical support for further experimental synthesis and testing. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
133.
To realize practical wide-area quantum communication,a satellite-to-ground network with partially entangled states is developed in this paper.For efficiency and security reasons,the existing method of quantum communication in distributed wireless quantum networks with partially entangled states cannot be applied directly to the proposed quantum network.Based on this point,an efficient and secure quantum communication scheme with partially entangled states is presented.In our scheme,the source node performs teleportation only after an end-to-end entangled state has been established by entanglement swapping with partially entangled states.Thus,the security of quantum communication is guaranteed.The destination node recovers the transmitted quantum bit with the help of an auxiliary quantum bit and specially defined unitary matrices.Detailed calculations and simulation analyses show that the probability of successfully transferring a quantum bit in the presented scheme is high.In addition,the auxiliary quantum bit provides a heralded mechanism for successful communication.Based on the critical components that are presented in this article an efficient,secure,and practical wide-area quantum communication can be achieved. 相似文献
134.
Na Wang Yuhu Wu Long Mi Jing Zhang Xuri Li Qinghong Fang 《Journal of Thermal Analysis and Calorimetry》2014,116(1):349-357
The mechanisms of the thermal degradation of polyhedral oligomeric octaphenylsilsesquioxane (OPS), octa(nitrophenyl)silsesquioxane (ONPS), and octa(aminophenyl)silsesquioxane (OAPS) were investigated. The –NO2 or –NH2 substituents on the phenyl group affected the mechanism of the POSS thermal degradation. The thermal stabilities of OPS, ONPS, and OAPS were characterized by TG and FTIR. Thermal degradation of OPS included mainly the degradation of caged polyhedral oligomeric silsesquioxane structures and phenyl groups. Nitro or amino substituents decreased its thermal stability. The thermal degradation processes of OPS, ONPS, and OAPS differed. Phenyl groups and cyclobutadiene were observed in the OPS degradation products. Oxygen radicals that caused intensive CO2 release between 350 and 450 °C were generated by the degradation of ONPS –NO2. OAPS released mainly aminophenyl groups at 370 °C, whereas a small number of phenyl groups decomposed at 500 °C. The OAPS reactivity could enhance the thermal stability of POSS structure in the polyimide OAPS composites. 相似文献
135.
Electrochemical Synthesis of Tetrahexahedral Rhodium Nanocrystals with Extraordinarily High Surface Energy and High Electrocatalytic Activity
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Neng‐Fei Yu Dr. Na Tian Dr. Zhi‐You Zhou Long Huang Jing Xiao Yu‐Hua Wen Prof. Shi‐Gang Sun 《Angewandte Chemie (International ed. in English)》2014,53(20):5097-5101
Noble metal nanocrystals (NCs) enclosed with high‐index facets hold a high catalytic activity thanks to the high density of low‐coordinated step atoms that they exposed on their surface. Shape‐control synthesis of the metal NCs with high‐index facets presents a big challenge owing to the high surface energy of the NCs, and the shape control for metal Rh is even more difficult because of its extraordinarily high surface energy in comparison with Pt, Pd, and Au. The successful synthesis is presented of tetrahexahedral Rh NCs (THH Rh NCs) enclosed by {830} high‐index facets through the dynamic oxygen adsorption/desorption mediated by square‐wave potential. The results demonstrate that the THH Rh NCs exhibit greatly enhanced catalytic activity over commercial Rh black catalyst for the electrooxidation of ethanol and CO. 相似文献
136.
“Click” Chemistry Mildly Stabilizes Bifunctional Gold Nanoparticles for Sensing and Catalysis
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Na Li Dr. Pengxiang Zhao Dr. Na Liu María Echeverria Dr. Sergio Moya Dr. Lionel Salmon Dr. Jaime Ruiz Prof. Dr. Didier Astruc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8363-8369
A large family of bifunctional 1,2,3‐triazole derivatives that contain both a polyethylene glycol (PEG) chain and another functional fragment (e.g., a polymer, dendron, alcohol, carboxylic acid, allyl, fluorescence dye, redox‐robust metal complex, or a β‐cyclodextrin unit) has been synthesized by facile “click” chemistry and mildly coordinated to nanogold particles, thus providing stable water‐soluble gold nanoparticles (AuNPs) in the size range 3.0–11.2 nm with various properties and applications. In particular, the sensing properties of these AuNPs are illustrated through the detection of an analogue of a warfare agent (i.e., sulfur mustard) by means of a fluorescence “turn‐on” assay, and the catalytic activity of the smallest triazole–AuNPs (core of 3.0 nm) is excellent for the reduction of 4‐nitrophenol in water. 相似文献
137.
Cube‐in‐Cube Hollow Cu9S5 Nanostructures with Enhanced Photocatalytic Activities in Solar H2 Evolution
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Miao Xu Min Wang Tiannan Ye Na Liang Lun Jin Dr. Jiantao Zai Prof. Xuefeng Qian 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13576-13582
Hydrogen produced from water under solar energy is an ideal clean energy source, and the efficiency of hydrogen production usually depends on the catalytic systems based on new compounds and/or a unique nanostructure. Herein, well‐defined cube‐in‐cube hollow Cu9S5 nanostructures have been successfully prepared with Cu2O nanocubes and CS2 as precursors, and single‐shell hollow Cu9S5 nanocubes could be obtained by replacing CS2 with Na2S. The formation mechanism of cube‐in‐cube hollow nanostructures has been proposed based on the Kirkendell effect and an outward self‐assembly process. Further studies revealed that the cube‐in‐cube hollow Cu9S5 nanostructures exhibited better photocatalytic activity toward solar H2 evolution and would be a promising photocatalyst in the solar hydrogen industry. 相似文献
138.
MnO2‐Modified Persistent Luminescence Nanoparticles for Detection and Imaging of Glutathione in Living Cells and In Vivo
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Dr. Na Li Wei Diao Yaoyao Han Dr. Wei Pan Tingting Zhang Prof. Bo Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16488-16491
Persistent luminescence nanoparticles (PLNPs) hold great promise for the detection and imaging of biomolecules. Herein, we have demonstrated a novel nanoprobe, based on the manganese dioxide (MnO2)‐modified PLNPs, that can detect and image glutathione in living cells and in vivo. The persistent luminescence of the PLNPs can be efficiently quenched by the MnO2 nanosheets. In the presence of glutathione (GSH), MnO2 was reduced to Mn2+ and the luminescence of PLNPs can be restored. The persistent luminescence property can allow detection and imaging without external excitation and avoid the background noise originating from the in situ excitation. This strategy can offer a promising platform for detection and imaging of reactive species in living cells or in vivo. 相似文献
139.
固相萃取-高效液相色谱法测定果蔬中异菌脲残留量 总被引:1,自引:0,他引:1
建立了固相萃取-高效液相色谱法测定果蔬中异菌脲残留量的方法。样品用乙腈提取,C18固相萃取柱净化,甲醇-水(70:30,V/V)为流动相,经C18液相色谱柱分离,DAD紫外检测器(218 nm)检测。结果表明:异菌脲在0.1~2.0 mg/L范围内线性关系良好(R2=0.9998),方法定量限(以S/N=10计)为0.05 mg/kg,在0.05,0.1,0.5 mg/kg添加水平下的加标回收率范围为81.3%~98.3%,相对标准偏差(n=6)为3.9%~8.9%。方法适用于大多数水果、蔬菜中异菌脲残留量的测定。 相似文献
140.
基于含有氨基类物质对三联吡啶钌电化学发光的促进作用,建立了直接测定组胺的电化学发光方法。通过MWCNT/ZnO/Nafion复合物膜修饰玻碳电极(GC)固定三联吡啶钌,研究了此工作电极在组胺溶液中的ECL发光行为。在最优的实验条件下,组胺质量浓度在1.0~1.0×104ng/mL范围内时其对数值与电化学发光信号呈良好的线性关系(R2=0.9968),检出限为0.64 ng/mL,组胺的加标回收率为96%~103%,RSD为2.7%。 相似文献