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1.
A novel reaction-based probe for the dual signaling of hydrogen sulfide (H2S) was investigated. The selective H2S-induced cleavage of the ether linkage of the 7-nitro-2,1,3-benzoxadiazole (NBD) and 7-hydroxycoumarin conjugate resulted in a dual signaling behavior. The colorimetric and fluorogenic signaling behaviors were attributed to the H2S-induced generation of 7-nitrobenzo-2,1,3-oxadiazole-4-thiol (NBD-SH) and 7-hydroxycoumarin, respectively. The signaling behavior was analyzed by ratiometry. The selective signaling of H2S over other common metal ions and anions was possible with a detection limit of 1.6 × 10−6 M in an aqueous DMSO solution. 相似文献
2.
Cristina Lavinia Nistor Dan Donescu Alain Perichaud Wael Ballout Marius Ghiurea 《Journal of Sol-Gel Science and Technology》2011,57(2):164-171
The sol–gel synthesis strategies combined with the templated growth of organic–inorganic hybrid networks provide access to
an immense new area of innovative multi-functional advanced materials. One possible way to prepare such new advanced materials
is to encapsulate liquid active agents (such as monomers, dyes, catalysts and hardeners) in microcapsules. Silica microcapsules
of tetraethylortosilicate (TEOS) and 3-(trimethoxysilyl)propyl methacrylate (MPTS) were prepared in a precursor-monomer/NH4OH water microemulsion system. Trimethylolpropane triacrylate (TMPTA)—a trifunctional monomer useful in manufacturing of coatings,
inks and adhesives—and a corresponding photoinitiator (DAROCUR 1173) were entrapped inside the obtained microcapsules. MPTS
was used to increase compatibility between TMPTA and the sol–gel precursors. As stability agent we added a “home made” product
resulted from functionalization of poly (ethylene glycol) methyl ether (MPEG) with (3-isocyanatopropyl) triethoxysilane (NCOTEOS).
Were obtained microcapsules containing incorporated monomer and having average particle size in range of 0.5–50 μm. Thermal
analysis, morphology study and the increase of the silica microcapsules average diameter, measured by DLS technique confirm
the monomer encapsulation. 相似文献
3.
Atanu Panja 《Supramolecular chemistry》2018,30(8):722-729
A cholesterol-based dithioacetal functionalised compound 1 has been designed, synthesised and successfully applied for the selective detection of Hg2+ ion. The specific Hg2+-induced deprotection of the thioacetal functionality of 1 resulted in sol-to-gel transition in DMF-H2O (1:1, v/v) via the formation of precursor aldehyde 3. This Hg2+-prompted rapid sol to gel conversion is insensitive to the nature of Hg2+-salt. In the study, other metal ions did not show any change. To the best of our knowledge, this is a first time report of a chemodosimeter that functions as a selective ‘naked-eye’ Hg2+-detector by showing in situ sol-to-gel conversion. 相似文献
4.
Highly selective detection of Hg2+ ion has been achieved using the push–pull-type purine nucleoside-based fluorescent sensor L1. The sensor L1 incorporating aza-18-crown-6 at C6 position of purine nucleoside, is highly sensitive and selective toward Hg2+ ion in CH3CN–H2O mixture (92/8, v/v). The detection limit for the fluorescent sensor L1 toward Hg2+ ion is 7.8 × 10−8. 相似文献
5.
Yan Tang Qing Lai Zhao Ke Zeng Pei Kai Miao Ke Zhou Wen Rui Tang Hong Fei Zhou Tao Liu Yi Peng Wang Gang Yang 《中国化学快报》2007,18(8):973-976
A novel benzoxazine monomer 3-(4-allyloxy)phenyl-3,4-dihydro-2H-6-(N-maleimido)-l,3-benzoxazine (AMB) was synthesized and structure was confirmed by FT-IR, 1H NMR. Thermal analysis (DSC) of AMB showed the introduction of allyloxy group melting point and exhibited a narrow and symmetric curing exothermic window. 相似文献
6.
A thymine and acridine conjugate (1), containing a benzylic carbon of thymine and an electron-rich aromatic ring (acridine) within the same molecule, was synthesized. Treatment of 1 with N-bromosuccinimide (NBS) in anhydrous chloroform in the presence of azobisisobutylnitrile produced a dibromo-substituted thymine–acridine conjugate (7) as a major product, in which the bromination was only observed on the acridine ring. Nuclear Overhauser effect (NOE) difference spectroscopy revealed that the actual bromination substitution was on C-2 and C-7 of acridine. Our results suggest that electrophilic aromatic substitution, not the expected benzylic radical reaction, takes place predominantly even when 1 is subjected to the NBS reaction condition, which favors radical processes. In addition, such selectivity is clearly solvent dependent. 相似文献
7.
Weiping Gan Xiaosong Cao Yi Shi Haifeng Gao 《Journal of polymer science. Part A, Polymer chemistry》2020,58(1):84-90
This article reports a chain-growth coupling polymerization of AB difunctional monomer via copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB n (n ≥ 2) monomers that spontaneously demonstrated a chain-growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step-growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole-based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain-growth mechanism and produced 3-arm star polymers and multi-arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, Mw/Mn ~ 1.05. When acid-degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 84–90 相似文献
8.
Fanrui Gao Xingke Yu Ling Liu Jinlei Chen Yongjun Lv Ting Zhao Jiecheng Ji Jiabin Yao Wanhua Wu Cheng Yang 《中国化学快报》2023,34(2):107558-214
Pillar[5]arene-based molecular universal joints(MUJs), bearing fused crown ether subring(MUJ1 and MUJ3) or a ring without ether oxygen atom(MUJ2), were synthesized and enantio–differentiated. Significant chiral inversion was observed for the crown ether-fused MUJs upon the addition of equivalent cations Na+, showing an anisotropy(g) factor of 0.014, while alkyl subring-fused MUJ2 showed no CD inversions. Unprecedentedly, sodium ion triggered rolling-in motion of the subring to the pillar[5]arene... 相似文献
9.
In this paper, a simple, selective and reusable electrochemical biosensor for the sensitive detection of mercury ions (Hg2+) has been developed based on thymine (T)-rich stem–loop (hairpin) DNA probe and a dual-signaling electrochemical ratiometric strategy. The assay strategy includes both “signal-on” and “signal-off” elements. The thiolated methylene blue (MB)-modified T-rich hairpin DNA capture probe (MB-P) firstly self-assembled on the gold electrode surface via Au–S bond. In the presence of Hg2+, the ferrocene (Fc)-labeled T-rich DNA probe (Fc-P) hybridized with MB-P via the Hg2+-mediated coordination of T–Hg2+–T base pairs. As a result, the hairpin MB-P was opened, the MB tags were away from the gold electrode surface and the Fc tags closed to the gold electrode surface. These conformation changes led to the decrease of the oxidation peak current of MB (IMB), accompanied with the increase of that of Fc (IFc). The logarithmic value of IFc/IMB is linear with the logarithm of Hg2+ concentration in the range from 0.5 nM to 5000 nM, and the detection limit of 0.08 nM is much lower than 10 nM (the US Environmental Protection Agency (EPA) limit of Hg2+ in drinking water). What is more, the developed DNA-based electrochemical biosensor could be regenerated by adding cysteine and Mg2+. This strategy provides a simple and rapid approach for the detection of Hg2+, and has promising application in the detection of Hg2+ in real environmental samples. 相似文献
10.
11.
《Angewandte Chemie (International ed. in English)》2023,62(51):e202314198
This invited Team Profile was created by Jiaxiang Chu at the University of Chinese Academy of Sciences (China) and Dominik Munz at Saarland University (Germany) . They recently reported isocyanide homologation mediated by aluminium(I) as a Fischer–Tropsch model reaction. Up to five molecules were coupled, and the step-by-step mechanism was elucidated. Combined mechanistic/computational work provided evidence that carbenes are the key intermediates during this process. “Evidence for Carbene Intermediates in Isocyanide Homologation by Aluminium(I)”, C. J. Zhang, F. Dankert, Z. A. Jiang, B. L. Wang, D. Munz, J. X. Chu, Angew. Chem. Int. Ed. 2023, 62, e202307352 . 相似文献
12.
Kinetics of fiber impregnation by a binder. Gradient generalization of Navier–Stokes–Darcy equations
P. A. Belov A. S. Borodulin L. P. Kobets G. V. Malysheva 《Polymer Science Series D》2016,9(2):205-208
A model of polymer composition material that is composed of a unidirectional fiber and binder has been considered. The space between two neighboring filaments of fibers is considered as a capillary along which the binder propagates during impregnation. In order to describe the flow process, a gradient generalization of the Navier–Stokes equation has been suggested. A corrected model of the flow of binder in the capillary-porous space of a unidirectional fiber material is developed on its basis. In particular cases, the found solution coincides with the Navier–Stokes–Darcy equations and conventional Navier–Stokes equation. The model that has been developed allows the refinement of the nonclassical effect of the existence of two boundary layers that appear during flow and may prevent it. 相似文献
13.
Chen Ruiyu Lu Shouxiang Li Changhai Li Manhou Lo Siuming 《Journal of Thermal Analysis and Calorimetry》2015,120(1):449-456
Journal of Thermal Analysis and Calorimetry - The thermal decomposition behavior of the commercial flame-retardant ethylene–propylene–diene monomer (EPDM) rubber was studied employing... 相似文献
14.
Zhao M Zhao C Jiang XQ Ji LN Mao ZW 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4469-4476
Two N-donor ligands (L(1) and L(2)) derived from a β-cyclodextrin (βCD) monomer and dimer were employed to mediate the hydrolytic activity and stability of the Ce(IV) ion in aqueous solution. Complexes Ce(IV)-L(1) and Ce(IV)-L(2) were prepared in situ and characterized by means of UV-vis and NMR measurements. Ce(IV)-L(1) catalyzed the hydrolysis of a DNA model, bis(4-nitrophenyl)phosphate (BNPP) with k(cat) = 5.2 × 10(-3) s(-1) (half-life t(1/2) ≈ 2 minutes) under mild conditions, which represented an approximate 130 million-fold acceleration with respect to the spontaneous hydrolysis of BNPP. The dinuclear species, [Ce(2)L(1)(2)(OH)(5)](3+), contributed splendidly to the catalytic efficiency which echoed the active species postulation of [Ce(2)(OH)(7)](+) in the literature. Ce(IV)-L(2) exhibited efficient binding with BNPP giving 1/K(M) = 2.1 × 10(5) M(-1) which exceeded other Ce(IV) species, e.g. [Ce(4)(OH)(15)](+), by 2 orders of magnitude, which highlighted the hydrophobicity effect of βCDs. Such a highly binding affinity leads to the second-order rate constant, k(cat)/K(M) = 2.3 × 10(2) M(-1) s(-1), which probably ranks as the highest in the non-enzymatic cleavage of BNPP under similar conditions. Additionally, Ce(IV)-L(2) showed favorable tolerance to basic aqua owing to the bulky protection of double βCD pendants. 相似文献
15.
Kumar Rohit Raj Abhishek Kardam Jyoti Kumar Arora Shalini Srivastava 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):797-801
The tendency of selenium to interact with heavy metals in presence of naturally occurring species has been exploited for the
development of green bioremediation of toxic metals from soil using Artificial Neural Network (ANN) modeling. The cross validation
of the data for the reduction in uptake of Hg(II) ions in the plant R. sativus grown in soil and sand culture in presence of selenium has been used for ANN modeling. ANN model based on the combination
of back propagation and principal component analysis was able to predict the reduction in Hg uptake with a sigmoid axon transfer
function. The data of fifty laboratory experimental sets were used for structuring single layer ANN model. Series of experiments
resulted into the performance evaluation based on considering 20% data for testing and 20% data for cross validation at 1,500
Epoch with 0.70 momentums The Levenberg–Marquardt algorithm (LMA) was found as the best of BP algorithms with a minimum mean
squared error at the eighth place of the decimal for training (MSE) and cross validation. 相似文献
16.
Songling Ma Jiwon Choi Xuemei Jin Hyun-Yi Kim Ji-Hye Yun Weontae Lee Kang-Yell Choi Kyoung Tai No 《Journal of computer-aided molecular design》2018,32(5):643-655
The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl–CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide–ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl–CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl–CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl–CXXC5 interaction. Overall, CXXC5–Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl–CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl–CXXC5 interaction disruptors. 相似文献
17.
Influence of the third monomer on lauryl methacrylate–methyl methacrylate emulsion terpolymerization
Rukhsana Shabnam Abu M. I. Ali Muhammad A. J. Miah Klaus Tauer Hasan Ahmad 《Colloid and polymer science》2013,291(9):2111-2120
An experimental study shows how the emulsion terpolymerization of lauryl methacrylate (LMA) and methyl methacrylate is influenced by the nature of the third monomer. The third monomer is either glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, or styrene. We report the synthesis of terpolymer particles with an appreciably high content of the very hydrophobic LMA (between 0.2515 and 0.238 molar fraction in the monomer mixture) in 60:40 weight water/ethanol mixture as the continuous phase, poly(vinyl pyrrolidone) as a polymeric steric stabilizer, and potassium peroxodisulfate as the initiator. The emulsion terpolymerization proceeds smoothly without the formation of coagulum and leads to particles with an average diameter clearly below 1 μm. We discuss the overall polymerization behavior regarding conversion–time curves, particle morphology, and glass transition temperature of the terpolymers in dependence of the lyophilicity/lyophobicity of the monomer mixture. 相似文献
18.
Yong-Kai Deng Ya-Rui Zhao Han Xu Prof. Dr. Xiang-Jian Kong Prof. Dr. La-sheng Long Prof. Dr. Lan-Sun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):614-617
Incorporating metal clusters within the skeleton of the organic polymers through a click reaction cannot only effectively prepare cluster–polymer composites, but also effectively avoid the cluster aggregation. Herein, an azide-containing lanthanide–titanium oxo cluster of Eu8Ti10-N3 ( Eu8Ti10-N3 =[Eu8Ti10(μ3-O)14(H2O)4(OAc)2(tbba)30(paza)4(THF)2] ⋅ 4 THF ⋅ 8 H2O ( 1 ), Htbba=4-tert-butylbenzoic acid, Hpaza=4-azidobenzoate, HOAc=acetic acid, THF=tetrahydrofuran) through an in situ solvothermal reaction of 4-azidobenzoic acid and 4-tert-butylbenzoic acid. Reaction of 1 with PEG ( PEG =methoxypoly(ethyleneglycol)alkyne, 2000 g mol−1) through CuI-catalyzed click chemistry generates a lanthanide–polymer composite of Eu8Ti10-N3@PEG ( 2 ). Investigation with IR, 1H NMR and ICP-OES of 2 indicates that the structural integrity of 1 is maintained in 2 . Study of the luminescent properties of 1 and 2 reveals that the quantum yield of 1 itself basically remains unchanged in 2 . Significantly, the formation of 2 cannot only effectively prevent the cluster 1 from aggregation, but also greatly enhance its solubility and adhesion to the substrate. Owing to the solubility and adhesion of luminescent materials being the key to their practical application, present work is thus of great significance for the development of metal cluster–polymer composite luminescent materials. 相似文献
19.
The 2,3,6-trinitro-β-d-glucopyranose as a monomer of nitrocellulose in the 4C1 chair conformation was selected for the alkaline hydrolysis of nitrocellulose within SN2 framework in the gas phase and in the bulk water solution. Both the direct and angular attacks of OH? in the hydrolysis reactions were considered. Geometries were optimized at the B3LYP/6-311G(d,p) level both in the gas phase and in bulk water solution. Effect of bulk water solution was modeled using the PCM approach. Nature of potential energy surfaces of the local minima and transition states was ascertained through harmonic vibrational frequency analysis. Intrinsic reaction coordinate calculations were also performed to validate the computed transition state structures. Effect of electron correlation on computed energies was considered at the MP2/cc-pVTZ//B3LYP/6-311G(d,p) level. It was found that the angular attack of OH? in the hydrolysis reaction will require significantly larger activation energy than the direct attack. Computed transition states correspond to the structure where the presence of hydrogen bonds between the OH? and various sites of nitrocellulose was the necessary stabilizing factor. The ring breaking through the C–O ring bond was not found to be the first step in the alkaline hydrolysis reactions. It was predicted that alkaline hydrolysis would be driven by the addition–elimination (substitution) reaction starting at the C3 site and will progress in the C2 → C6 direction. Entropy of system in water solution will have profound effect on alkaline hydrolysis reaction of nitrocellulose. 相似文献
20.
Amlan K. Roy 《Journal of mathematical chemistry》2014,52(5):1405-1413
Accurate low and high-lying bound states of Tietz–Hua oscillator potential are presented. The radial Schrödinger equation is solved efficiently by means of the generalized pseudospectral method that enables optimal spatial discreti zation. Both $\ell =0$ and rotational states are considered. Ro-vibrational levels of six diatomic molecules viz., H $_2$ , HF, N $_2$ , NO, O $_2$ , O $_2^+$ are obtained with good accuracy. Most of the states are reported here for the first time. A detailed analysis of variation of eigenvalues with $n, \ell $ quantum numbers is made. Results are compared with literature data, wherever possible. These are also briefly contrasted with the Morse potential results. 相似文献