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51.
Prof. Dr. Masakazu Nambo Yasuyo Tahara Dr. Jacky C.-H. Yim Prof. Dr. Cathleen M. Crudden 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(8):1923-1926
A new method for the synthesis of benzhydryl amines from the reaction of readily available sulfone derivatives with amines is described. The Cu-catalyzed desulfonylative amination not only provides structurally diverse benzhydryl amines in good yields, but is also applicable to iterative and intramolecular aminations. Control experiments suggested that the formation of a Cu-carbene intermediate generated from the sulfone substrate, which represents a new route for desulfonylative transformations. 相似文献
52.
Zujin Zhao Tao Jiang Yanju Guo Liyuan Ding Bairong He Zhengfeng Chang Jacky W. Y. Lam Jianzhao Liu Carrie Y. K. Chan Ping Lu Liwen Xu Huayu Qiu Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(11):2265-2274
Hydrosilylation polymerizations of 1,1‐dimethyl‐2,5‐bis(4‐ethynylphenyl)‐3,4‐diphenylsilole with aromatic silylhydrides including 1,4‐bis(dimethylsilyl)benzene, 4,4′‐bis(dimethylsilyl)biphenyl, 2,5‐bis(dimethylsilyl)thiophene, and 2,7‐bis(dimethylsilyl)‐9,9‐dihexylfluorene in the presence of Rh(PPh3)3Cl catalyst in refluxed tetrahydrofuran afford a series of silole‐containing poly(silylenevinylene)s. Under optimum condition, the alkyne polyhydrosilylation reactions progress efficiently and regioselectively, yielding polymers with high molecular weights (Mw up to 95,300) and good stereoregularity (E content close to 99%) in high yields (up to 92%). The polymers are processable and thermally stable, with high decomposition temperatures in the range of 420?449 °C corresponding to 5% weight loss. They are weakly fluorescent in the solution state but become emissive in the aggregate and film states, demonstrating their aggregation‐enhanced emission characteristics. The explosive sensing capabilities of the polymers are examined in both solution and aggregate states. The emissions of the polymers aggregates in aqueous mixture are quenched more efficiently by picric acid in an exponential pattern with high quenching constants (up to 27,949 L mol?1), suggesting that the polymers aggregates are sensitive chemosensors for explosive detection. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
53.
Yuning Hong Hao Xiong Jacky Wing Yip Lam Dr. Matthias Häußler Dr. Jianzhao Liu Yong Yu Yongchun Zhong Dr. Herman H. Y. Sung Dr. Ian D. Williams Prof. Kam Sing Wong Prof. Ben Zhong Tang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(4):1232-1245
Whereas most conventional DNA probes are flat disklike aromatic molecules, we explored the possibility of developing quadruplex sensors with nonplanar conformations, in particular, the propeller‐shaped tetraphenylethene (TPE) salts with aggregation‐induced emission (AIE) characteristics. 1,1,2,2‐Tetrakis[4‐(2‐triethylammonioethoxy)phenyl]ethene tetrabromide (TPE‐ 1 ) was found to show a specific affinity to a particular quadruplex structure formed by a human telomeric DNA strand in the presence of K+ ions, as indicated by the enhanced and bathochromically shifted emission of the AIE fluorogen. Steady‐state and time‐resolved spectral analyses revealed that the specific binding stems from a structural matching between the AIE fluorogen and the DNA strand in the folding process. Computational modeling suggests that the AIE molecule docks on the grooves of the quadruplex surface with the aid of electrostatic attraction. The binding preference of TPE‐ 1 enables it to serve as a bioprobe for direct monitoring of cation‐driven conformational transitions between the quadruplexes of various conformations, a job unachievable by the traditional G‐quadruplex biosensors. Methyl thiazolyl tetrazolium (MTT) assays reveal that TPE‐ 1 is cytocompatible, posing no toxicity to living cells. 相似文献
54.
Arnaud Cuisset Francis Hindle Jacky Laureyns Eugne Bychkov 《Journal of Raman spectroscopy : JRS》2010,41(9):1050-1058
The alkali metal halide doping of gallium‐sulfide glasses yields improvements in the optical, thermal and glass forming properties. To understand these improvements, the short‐range order of xCsCl(1 − x)Ga2S3 glasses was probed by Raman spectroscopy. Raman spectra have been interpreted using density functional theory (DFT) harmonic frequency calculations on specific clusters of GaS4H4 and/or GaS3H3Cl tetrahedral subunits. The assignment of the observed vibrational bands confirms the main structural conclusions obtained with X‐ray and neutron diffraction experiments and gives some new insights into the gallium‐network present in the xCsCl(1 − x)Ga2S3 glasses. At the lowest concentration, the observed spectrum may be interpreted with small clusters such as dimers and trimers connected by corner‐sharing (CS) GaS4H4 tetrahedral subunits. The vibrational fingerprints of tri‐clusters with three‐fold coordinated sulfur atoms have also been identified; however, no Raman signature of chlorine‐doped subunits has been found to be caused by their insufficient intensity. For higher CsCl concentrations, distinct spectral features corresponding to chlorine‐doped clusters appear and are increasing in intensity with x. In other words, undoped and Cl‐doped tetrahedra coexist in the xCsCl(1 − x)Ga2S3 glasses. The added chlorine atoms induce a fragmentation of the glass network and replace the sulfur atoms in the CS tetrahedral environment. The comparison of the observed spectra with theoretical predictions and diffraction data favoured one‐fold coordinated chlorine atoms in the glass network. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
55.
Hongqin Liu Gaëlle Piret Brigitte Sieber Jacky Laureyns Pascal Roussel Wenguo Xu Rabah Boukherroub Sabine Szunerits 《Electrochemistry communications》2009,11(5):945-949
The paper reports on the use of electrochemical impedance spectroscopy to determine the doping character and carrier density of freshly prepared and annealed ZnO nanostructures. The ZnO nanostructures were obtained by chemical oxidation of metallic Zn in a 5% N,N-dimethylformamide (DMF) aqueous solution at 95 °C for 24 h. The as-grown nanostructured ZnO samples display a high donor density of 3.71 ± 0.88 × 1021 cm?3. Annealing at 100 and 200 °C did not have any effect on the donor density while thermal annealing at 300 °C in air for 1 h induced a decrease in the doping concentration without affecting the surface morphology. 相似文献
56.
Fluorescent "light-up" bioprobes based on tetraphenylethylene derivatives with aggregation-induced emission characteristics 总被引:1,自引:0,他引:1
Tong H Hong Y Dong Y Häussler M Lam JW Li Z Guo Z Guo Z Tang BZ 《Chemical communications (Cambridge, England)》2006,(35):3705-3707
Aggregation in poor solvents and complexation with calf thymus DNA and bovine serum albumin turn "on" the fluorescence of tetraphenylethylene derivatives, due to the restriction of intra-molecular rotations of the dyes in the aggregates and complexes. 相似文献
57.
Acoustic wave detection of various underivatized amino acids that were hydrodynamically introduced into and electrokinetically migrated along a capillary tube has been achieved. The detection principle is based on the measurement of the ultrasonic absorption and density change of the aqueous amino acid samples as they pass by the detection zone. Acoustic wave detection of underivatized leucine was obtained in the ultrasonic frequency range of 100 kHz to 20 MHz. This was accomplished by measuring the insertion loss from the vector ratio of the signal voltage to the source voltage obtained at the generating and receiving piezoelectric transducers. Linear concentration dependence of the insertion loss of underivatized leucine was established. The effects of capillary internal diameter, capillary geometry (square and circular), buffer concentration, buffer pH and acoustic wave frequency on the insertion loss were investigated. Subsequently, separations of underivatized amino acids (leucine/histidine and leucine/tryptophan) were performed under different buffer conditions and different capillary geometry. 相似文献
58.
ZuJin Zhao DanDan Liu Jacky Wing Yip Lam Ping Lu Bing Yang YuGuang Ma Ben Zhong Tang 《中国科学:化学(英文版)》2010,53(11):2311-2317
The theoretical calculation of the charge mobility of 2,5-bis(trialkylsilylethynyl)-1,1,3,4-tetraphenylsiloles is presented. B3LYP/6-31* calculations demonstrated that these silole molecules possessed large coupling matrix elements and reorganization energies for electron and hole transfers and high electron mobilities. The bulkiness of the trialkyl substituents influenced the charge mobility of the silole molecules, with the smaller trimethyl group imparting higher charge mobility than triethyl and triisopropyl substituents. 相似文献
59.
60.
Jacky Cresson 《随机分析与应用》2018,36(2):224-239
We discuss a method, which was popularized by E. J. Allen and that is frequently used in applications to construct SDE models. The derivation procedure is based on information about the elementary processes involved in the dynamics and their corresponding probabilities. We formulate criteria for the viability of the resulting models. In particular, explicit necessary and sufficient conditions are deduced for the non-negativity and/or boundedness of solutions. Moreover, we show that the class of deterministic models for which the construction leads to an admissible SDE extension is strongly limited. Several examples are presented to illustrate the implications of our results. 相似文献