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排序方式: 共有686条查询结果,搜索用时 15 毫秒
1.
2.
A novel organoantimony complex of 6-cyclohexyl-6,7-dihydrodibenzo[c,f] [1,5]azastibocin-12(5H)-yl nitrate ( 2 ) was synthesized and systematically characterized by techniques such as NMR spectra, TG-DSC, and X-ray diffraction. It was found that the complex 2 exhibits relatively strong Lewis acidity (3.3 < Ho ≤ 4.8) and could be employed as a water tolerant Lewis acid catalyst for the synthesis of synthetically valuable benzimidazole derivatives starting from aldehydes and arylenediamines. This catalytic system shows excellent tolerance toward a wide variety of functional groups, such as methyl, methoxyl, fluoro, chloro, bromo, nitro, cyan, trifluoromethyl, 1-naphthaldehyde, furfural and n-butyl, together with facile reusability in 5 times scale enlarged synthesis. 相似文献
3.
Povilas Virbickas Gerda Ziziunaite Arunas Ramanavicius Aušra Valiūnienė 《Electroanalysis》2023,35(4):e202200230
In this research a Hg2+ ion biosensor was developed by combining Prussian blue (PB) with glucose oxidase (GOx) – an enzyme that can be inhibited by Hg2+ ions. An application of PB in the design of Hg2+ ion biosensor enabled detecting changes in hydrogen peroxide reduction current at low operational potential of 0.2 vs Ag|AgCl,KClsat. The described Hg2+ ion biosensor exhibited wide linear range from 27 μM to 247 μM of Hg2+ and higher maximal detectable concentration of Hg2+ than other GOx inhibition-based biosensors, making it convenient for the analysis of samples with high concentration of Hg2+ ions. 相似文献
4.
Yuen Cheong Tse Dr. Robert Hein Edward J. Mitchell Zongyao Zhang Prof. Paul D. Beer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(58):14550-14559
Anion receptors employing two distinct sensory mechanisms are rare. Herein, we report the first examples of halogen-bonding porphyrin BODIPY [2]rotaxanes capable of both fluorescent and redox electrochemical sensing of anions. 1H NMR, UV/visible and electrochemical studies revealed rotaxane axle triazole group coordination to the zinc(II) metalloporphyrin-containing macrocycle component, serves to preorganise the rotaxane binding cavity and dramatically enhances anion binding affinities. Mechanically bonded, integrated-axle BODIPY and macrocycle strapped metalloporphyrin motifs enable the anion recognition event to be sensed by the significant quenching of the BODIPY fluorophore and cathodic perturbations of the metalloporphyrin P/P+. redox couple. 相似文献
5.
Dual Esterase‐ and Steroid‐Responsive Energy Transfer Modulation of Ruthenium(II) and Rhenium(I) Complex Functionalized Gold Nanoparticles 下载免费PDF全文
Dr. Frankie Chi‐Ming Leung Dr. Vonika Ka‐Man Au Dr. Hai‐Ou Song Prof. Dr. Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16448-16454
A number of adamantane‐containing ruthenium(II) and rhenium(I) complexes have been synthesized, characterized, and noncovalently functionalized with β‐cyclodextrin‐capped gold nanoparticles (β‐CD–GNPs) through the host–guest interaction between cyclodextrin and adamantane. The resultant nanoconjugates have been characterized by transmission electron microscopy (TEM), energy‐dispersive X‐ray analysis (EDX), and 2D ROESY 1H NMR experiments. The Förster resonance energy transfer (FRET) properties of the nanoconjugates can be modulated by both esterase‐accelerated hydrolysis and competitive displacement of steroid, by monitoring the emission intensity and luminescence lifetime. The FRET efficiencies are found to vary with the nature of the chromophores and the length of the spacer between the transition metal complexes and the GNPs. This work constitutes a “proof‐of‐principle” assay method for the dual‐functional detection of important classes of biomolecules, such as enzymes and steroids. 相似文献
6.
Utilization of Active Ni to Fabricate Pt–Ni Nanoframe/NiAl Layered Double Hydroxide Multifunctional Catalyst through In Situ Precipitation 下载免费PDF全文
Dr. Liangfeng Luo Haiyuan Lu Prof. Gang Zhou Prof. Weixin Huang Prof. Xun Hong Prof. Yuen Wu Prof. Yadong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13181-13185
Integration of different active sites into metallic catalysts, which may impart new properties and functionalities, is desirable yet challenging. Herein, a novel dealloying strategy is demonstrated to decorate nickel–aluminum layered double hydroxide (NiAl–LDH) onto a Pt–Ni alloy surface. The incorporation of chemical etching of Pt–Ni alloy and in situ precipitation of LDH are studied by joint experimental and theoretical efforts. The initial Ni‐rich Pt–Ni octahedra transform by interior erosion into Pt3Ni nanoframes with enlarged surface areas. Furthermore, owing to the basic active sites of the decorated LDH together with the metallic sites of Pt3Ni, the resulting Pt–Ni nanoframe/NiAl–LDH composites exhibit excellent catalytic activity and selectivity in the dehydrogenation of benzylamine and hydrogenation of furfural. 相似文献
7.
8.
Summary Heat transfer to fibers formed in dry spinning has been subjected to fundamental analysis. Solutions of the equation of energy have been derived and tested with experimental data. Results were deemed satisfactory in view of the accuracy of the experimental data. The present work is believed to yield a good representation of the heat transfer in the dry spinning process.Nomenclature
h
heat transfer coefficient, cal/cm2 °C sec
-
k
thermal conductivity, cal/cm °C sec
-
r
radial distance, cm
-
t
time, sec
-
Z
axial distance, cm
-
A
surface area, cm2
-
A
n
or n-th root of
-
A
0
energy required for solvent evaporation, cal/sec cm3
-
C
p
specific heat cal/gm °C
-
J
0
Bessel function of first kind, order zero
-
J
1
Bessel function of first kind, order one
-
J
2
Bessel function of first kind, order two
-
N
k/(R
2
C
p
V)
-
Q
volumetric flow rate cm3/sec
-
R
outside radius, cm
-
T
point temperature, °C
-
T
S
surface temperature °C
-
T
0
initial fiber temperature °C
-
T
ambient air temperature, °C
-
average fiber temperature, °C
-
1
average fiber temperature of preceding segment, °C
-
V
average fiber velocity relative to air strean, cm/sec
-
V
r
radial velocity component, cm/sec
-
V
z
axial velocity components, cm/sec
-
V
direction velocity component cm/sec
-
W
weight of solvent evaporated in a given fiber segment, gms
-
n
a solution of the equation J
0(X)=0
-
heat of vaporization of solvent, cal/gm
-
dimension
-
r/R
-
density, gms/cc 相似文献
9.
Elnaz Miandoabchi Farzaneh Daneshzand Reza Zanjirani Farahani Wai Yuen Szeto 《The Journal of the Operational Research Society》2015,66(6):894-913
This paper aims to model and investigate the discrete urban road network design problem, using a multi-objective time-dependent decision-making approach. Given a base network made up with two-way links, candidate link expansion projects, and candidate link construction projects, the problem determines the optimal combination of one-way and two-way links, the optimal selection of capacity expansion projects, and the optimal lane allocations on two-way links over a dual time scale. The problem considers both the total travel time and the total CO emissions as the two objective function measures. The problem is modelled using a time-dependent approach that considers a planning horizon of multiple years and both morning and evening peaks. Under this approach, the model allows determining the sequence of link construction, the expansion projects over a predetermined planning horizon, the configuration of street orientations, and the lane allocations for morning and evening peaks in each year of the planning horizon. This model is formulated as a mixed-integer programming problem with mathematical equilibrium constraints. In this regard, two multi-objective metaheuristics, including a modified non-dominated sorting genetic algorithm (NSGA-II) and a multi-objective B-cell algorithm, are proposed to solve the above-mentioned problem. Computational results for various test networks are also presented in this paper. 相似文献
10.
Dr. Song Song Vincent Fung Kin Yuen Dr. Lu Di Dr. Qiming Sun Prof. Dr. Kang Zhou Prof. Dr. Ning Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20018-20022
Production of renewable, high-value N-containing chemicals from lignocellulose will expand product diversity and increase the economic competitiveness of the biorefinery. Herein, we report a single-step conversion of furfural to pyrrole in 75 % yield as a key N-containing building block, achieved via tandem decarbonylation–amination reactions over tailor-designed Pd@S-1 and H-beta zeolite catalytic system. Pyrrole was further transformed into dl -proline in two steps following carboxylation with CO2 and hydrogenation over Rh/C catalyst. After treating with Escherichia coli, valuable d -proline was obtained in theoretically maximum yield (50 %) bearing 99 % ee. The report here establishes a route bridging commercial commodity feedstock from biomass with high-value organonitrogen chemicals through pyrrole as a hub molecule. 相似文献