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81.
82.
Yuanhong Xu Zhaozi Lv Yong Xia Yanchao Han Baohua Lou Erkang Wang 《Analytical and bioanalytical chemistry》2013,405(11):3549-3558
Graphene-nanosheet-based highly porous magnetite nanocomposites (GN-HPMNs) have been prepared using a simple solvothermal method and used as an immobilization matrix for the fabrication of a solid-state electrochemiluminescence (ECL) sensor on paper-based chips. Highly porous Fe3O4 nanocrystal clusters were coated with acrylate and wrapped tightly on the skeleton of graphene nanosheets. The structures and sizes of the GN-HPMNs could be tuned by varying the proportions of the solvents ethylene glycol and diethylene glycol. Then, the relatively highly porous ones with an average diameter of about 65 nm were combined with Nafion to form composite films on an electrode surface for immobilization of Ru(bpy)3 2+ (bpy is 2,2′-bipyridine). Because of their porosity, negatively charged surface, and cooperative characteristics of magnetic nanomaterials and graphene, under an external magnetic field, the GN-HPMNs ensured effective immobilization, excellent electron transfer, and long-term stability of Ru(bpy)3 2+ in the composite film. The sensor developed exhibited excellent reproducibility with a relative standard deviation of 0.65 % for 30 continuous cycles. It was found to be much more favorable for detecting compounds containing tertiary amino groups and DNAs with guanine and adenine. A detection limit (signal-to-noise ratio of 3) of 5.0 nM was obtained for tripropylamine. As an application example, 0.5 nM single-nucleotide mismatch could be detected. This was the first attempt to introduce magnetic nanomaterials and an external magnetic field into paper-based chips. The sensor developed has the advantages of high sensitivity, good stability, and wide potential applicability as well as simplicity, low cost, and good disposability. Figure
Schematic diagram of using graphene-nanosheet-based highly porous magnetite nanocomposites for fabrication of a solid-state electrochemiluminescence sensor on paper-based chips and application example of the developed sensor for single-nucleotide mismatch discrimination 相似文献
83.
Total synthesis of α-elvucitabine was achieved in 26% overall yield by a concise nine-step procedure starting from L-lyxose, with trimethylsilyl trifluoromethaneoulfonate (TMSOTf)–mediated stereocontrolled α-N-glycosidation and olefination through Barton–McCombie deoxygenation being the key steps, and the stereochemistry of the product was determined by nuclear Overhauser effect spectroscopy. 相似文献
84.
A selective and effective oxidation of alcohols into the corresponding aldehydes and ketones, respectively, with a new reagent, ferric(III) nitrate supported on kieselguhr, under heterogeneous conditions is reported. 相似文献
85.
A new and convenient procedure for the preparation of aldehydes and ketones by the oxidation of the corresponding primary and secondary alcohols with a neutral potassium dichromate-dimethylformamide system is described. 相似文献
86.
Jian-Feng Zhou Xiao-Jun Sun Feng-Wen Lou Meng Lv Lu-Lu Zhang 《Research on Chemical Intermediates》2013,39(3):1401-1408
A series of 3,3′-(4-arylpyridine-2,6-diyl)bis(2H-chromen-2-one) derivatives have been synthesized by the one-pot, three-component reaction of 3-acetylcoumarin, an aromatic aldehyde, and ammonium acetate in acetic acid under microwave irradiation. This procedure has the major advantages of short reaction time, good yields, low energy consumption, easy operation, and environmental friendliness. All of the products were characterized by IR and NMR spectroscopy, MS, and elemental analysis. 相似文献
87.
S. Y. Lou 《Studies in Applied Mathematics》2015,134(3):372-402
A consistent Riccati expansion (CRE) is proposed for solving nonlinear systems with the help of a Riccati equation. A system having a CRE is then defined to be CRE solvable. The CRE solvability is demonstrated quite universal for various integrable systems including the Korteweg–de Vries, Kadomtsev–Petviashvili, Ablowitz–Kaup–Newell–Segur (and then nonlinear Schrödinger), sine‐Gordon, Sawada–Kotera, Kaup–Kupershmidt, modified asymmetric Nizhnik–Novikov–Veselov, Broer–Kaup, dispersive water wave, and Burgers systems. In addition, it is revealed that many CRE solvable systems share a similar determining equation describing the interactions between a soliton and a cnoidal wave. They have a common nonlocal symmetry expression and they possess a formally universal once Bäcklund transformation. 相似文献
88.
89.
Miao Wan Zhilin Meng Hongxiang Lou Lei Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(50):14065-14069
A trityl ion mediated C H functionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemoselectivity and good functional group tolerance. The protocol also exhibits excellent regio‐ and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highly functionalized disubstituted 2,5‐trans tetrahydrofurans (THF), 2,6‐trans tetrahydropyrans (THP), 2,6‐trans dihydropyrans (DHP), and 1,3‐trans isochromans, and highlighting the capacity of the protocol in complex molecule synthesis. 相似文献
90.
Shao‐Jie Lou Dan‐Qian Xu Zhen‐Yuan Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(39):10498-10503
A novel and facile C H bond fluorination proceeds under remarkably mild conditions (close to room temperature in most cases). Both aromatic and olefinic C(sp2) H bonds with a wide range of electronic properties are selectively fluorinated in the presence of a catalytic amount of simple, cheap, and nontoxic nitrate as the promoter. A PdII/PdIV catalytic cycle that is initiated by an in situ generated cationic [Pd(NO3)]+ species was proposed based on preliminary mechanistic studies. 相似文献