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1.
Xiaofan Ji Kelong Zhu Xuzhou Yan Yingjie Ma Jinying Li Bingjie Hu Yihua Yu Feihe Huang 《Macromolecular rapid communications》2012,33(14):1197-1202
All the previously reported supramolecular polymers based on crown ether‐based molecular recognition have been prepared in anhydrous organic solvents. This is mainly due to the weakness of crown ether‐based molecular recognition in the presence of water. Here we report a linear supramolecular polymer constructed from a heteroditopic monomer in an aqueous medium driven by crown ether‐based molecular recognition through the introduction of electrostatic attraction. In addition, the reversible transition between the linear supramolecular polymer and oligomers is achieved by adding acid and base. This study realizes the breakthrough of the solvent for supramolecular polymerization driven by crown ether‐based molecular recognition from anhydrous organic solvents to aqueous media. It is helpful for achieving supramolecular polymerization driven by crown ether‐based molecular recognition in a completely aqueous medium. 相似文献
2.
利用氢键驱动的“之”字型芳酰胺为“引导”组分,本文报道了三个单环、双环及三环分子的动态共价键自组装。单环分子是一个四氨基衍生物,从“U”-型二醛和卟啉二胺的2+2缩合后经NaBH3CN还原制备。而双环及三环分子以刚性的三氨及四氨寡聚体为模板,从两个六组分反应制备得到。 相似文献
3.
Visible‐light‐driven self‐cleaning SERS substrate of silver nanoparticles and graphene oxide decorated nitrogen‐doped titania nanotube array
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Graphene oxide (GO) and silver nanoparticles (Ag NPs) sequentially decorated nitrogen‐doped titania nanotube array (N‐TiO2 NTA) had been designed as visible‐light‐driven self‐cleaning surface‐enhanced Raman scattering (SERS) substrate for a recyclable SERS detection application. N‐TiO2 NTA was fabricated by anodic oxidation and then doping nitrogen treatment in ammonia atmosphere, acting as a visible‐light‐driven photocatalyst and supporting substrate. Ag/GO/N‐TiO2 NTA was prepared by decorating GO monolayer through an impregnation process and then depositing Ag NPs through a polyol process on the surface of N‐TiO2 NTA, acting as the collection of organic molecule and Raman enhancement. The SERS activity of Ag/GO/N‐TiO2 NTA was evaluated using methyl blue as an organic probe molecule, revealing the analytical enhancement factor of 4.54 × 104. Ag/GO/N‐TiO2 NTA was applied as active SERS substrate to determine a low‐affinity organic pollutant of bisphenol A, revealing the detection limit of as low as 5 × 10?7 m . Ag/GO/N‐TiO2 NTA could also achieve self‐cleaning function for a recycling utilization through visible‐light‐driven photocatalytic degradation of the adsorbed organic molecules. Ag/GO/N‐TiO2 NTA has been successfully reused for five times without an obvious decay in accuracy and sensitivity for organic molecule detection. The unique properties of this SERS substrate enable it to have a promising application for the sensitive and recyclable SERS detection of low‐affinity organic molecules. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
三元配合物钯(Ⅱ)-2,2''-联吡啶-L-天冬氨酸与DNA作用研究 总被引:1,自引:0,他引:1
The ternary complex Pd(Ⅱ)-2,2‘-bipyridine-L-asparagic acid was synthesized and characterized by elemental analysis, IR-spectra and molar conductance. The formula of the complex is Pd(bipy)(L-asp). The interaction of the complex with DNA has been studied by UV-spectra, fluorescence spectra, CD-spectra and gel electrophoresis. The results showed that the interaction of the complex with DNA performed mainly in intercalative mode and the extent of interaction was dependent on the concentration of the complex. 相似文献
5.
Pavel Hradil Lubomír Kvapil Jan Hlav
Tom Weidlich Antonín Ly
ka Karel Lemr 《Journal of heterocyclic chemistry》2000,37(4):831-837
The cyclization of phenacyl anthranilate has been studied with the aim to develop the synthesis of 2‐(2′‐aminophenyl)‐4‐phenyloxazole. However, a different course of the reaction than expected was observed. 2‐Phenyl‐2‐hydroxymethyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 3a ) was formed by the reaction of phenacyl anthranilate ( 2 ) with ammonium acetate under various conditions. 3‐Hydroxy‐2‐phenyl‐4(1H)‐quinolinone ( 4 ) arose by heating compound 3a in acetic acid. The same compound was obtained by melting compound 3a , but the yield was lower. Different types of products resulted in the reaction of compound 3a with acetic anhydride. Under mild conditions acetylated products 2‐acetoxymethyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 7a ) and 2‐acetoxymethyl‐3‐acetyl‐2‐phenyl‐4‐oxo‐1,2,3,4‐tetrahydroquinazoline ( 8 ) were prepared. If the reaction was carried out under reflux of the reaction mixture, molecular rearrangement took place to give cis and trans 2‐methyl‐4‐oxo‐3‐(1‐phenyl‐2‐acetoxy)vinyl‐3,4‐dihydroquinazolines ( 9a and 9b ). All prepared compounds have been characterised by their 1H, 13C and 15N NMR spectra, IR spectra and MS. 相似文献
6.
Silicomolybdate‐doped‐glutaraldehyde‐cross‐linked poly‐L ‐lysine (PLL‐GA‐SiMo) film modified glassy carbon electrode was successfully prepared by means of electrostatically trapping the silicomolybdate anion in PLL‐GA cationic coating. The PLL‐GA‐SiMo film was stable and the charge transport through the film was fast. The modified electrode shows excellent electrocatalytic activity towards bromate reduction with significant reduction of overpotential. In amperometric determination of bromate, the calibration plot was linear over the concentration range of 5×10?5 to 1.2×10?3 M with a sensitivity of 3.6 μA mM?1. Furthermore, PLL‐GA‐SiMo film electrode showed fast response and good stability. 相似文献
7.
Michael J. Hearn Eleanor R. Webster Michael H. Cynamon 《Journal of heterocyclic chemistry》2005,42(6):1225-1229
1‐Piperidino‐3‐arylthioureas, of interest in the investigation of novel heterocyclic structures for their anti‐tubercular activity, may be conveniently prepared in good yield and purity by the reaction of 1‐arninopiperi‐dine with aryl isothiocyanates in ethanol. The reaction takes place readily without the complication of thiourethane contaminants, and the products may be suitably identified by significant characteristics in the infrared spectra and the hydrogen and carbon magnetic resonance spectra. 相似文献
8.
A series of Ag‐enhanced TiO2–x/C composites (Ag/TiO2–x/C composites) with metal‐organic frameworks (MOFs) as precursors were prepared, and their photocatalytic activities were evaluated by the UV‐light driven photodegradation behaviors of methyl blue (MB). The as‐obtained samples were characterized by several techniques such as SEM, XRD, N2‐adsorption, XPS, UV/Vis spectrophotometry and UV/Vis diffuse‐reflectance spectra. The best photocatalytic performance was achieved in Ag/TiO2–x/C composite pyrolyzed at 1000 °C (ATC‐P10) due to rapid capture of electrons caused by silver doping, higher density of TiO2–x lattice oxygen vacancies for better trapping of electrons, and high surface area due to reduction and evaporation of metallic Zn. No obvious deactivation was observed after 10 cycles of UV‐light degradation of MB under the same experimental conditions. This report reveals a new approach to prepare stable and highly efficient UV‐light‐driven photocatalysts for organic pollutants in water. 相似文献
9.
This paper describes the synthesis of protein microtube motors having a urease interior surface and highlights their nonbubble‐propelled behavior driven by enzymatic reaction (urea→NH3 and CO2). The precursor microtubes were prepared by layer‐by‐layer assembly using a track‐etched microporous polycarbonate membrane. Immobilization of a urease on the internal wall was accomplished using avidin–biotin interaction. The tubules swam smoothly in an aqueous media containing a physiological concentration of urea. Each tubule was rotating laterally while moving forward. It is remarkable that the microtubes were digested completely by proteases, demonstrating perfect biodegradability. 相似文献
10.
Ten new ortho, meta and para substituted derivatives of 2‐benzylthio‐6‐aminouracils have been prepared. Electron Impact (EI) induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of the M+‐ and the selected fragment ions of these compounds is discussed. The data obtained create the basis for dinstinguishing isomers. The 1H and 13C NMR spectra of these compounds were assigned unambiguously using a combination of heteronuclear (HETCOR) spectra the chemical shifts. The data derived from these spectra can be used to differentiate the isomers. 相似文献
11.
Hyunji Jung Dr. Abhishek Dubey Hyun Jung Koo Dr. Vaishali Vajpayee Dr. Timothy R. Cook Dr. Hyunuk Kim Prof. Se Chan Kang Prof. Peter J. Stang Prof. Ki‐Whan Chi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(21):6709-6717
The synthesis of six new [2+2] metallarectangles through the coordination‐driven self‐assembly of octahedral RuII‐based acceptors with ambidentate pyridyl‐carboxylate donors is described. These molecular rectangles are fully characterized by 1H NMR spectroscopy, high‐resolution electrospray mass spectrometry, and single‐crystal X‐ray diffraction. In each case, despite the possible formation of multiple isomers, based on the relative orientation of the pyridyl and carboxylate groups (head‐to‐head versus head‐to‐tail), evidence for the formation of a single preferred ensemble (head‐to‐tail) was found in the 1H NMR spectra. Furthermore, the cytotoxicities of all of the rectangles were established against A549 (lung), AGS (gastric), HCT‐15 (colon), and SK hep 1 (liver) human cancer cell lines. The cytotoxicities of rectangles that contained the 5,8‐dihydroxy‐1,4‐naphthaquinonato bridging moiety between the Ru centers ( 9 – 11 ) were particularly high against AGS cancer cells, with IC50 values that were comparable to that of reference drug cisplatin. 相似文献
12.
Yoichi Habata Makoto Takeshita Yoji Fukuda Sadatoshi Akabori Jerald S. Bradshaw 《Journal of heterocyclic chemistry》2001,38(6):1323-1327
Dedicated to Professor Jerald S. Bradshaw Bis(2′‐hydroxyethyl) 2,6‐pyridinedicarboxylate (1) was prepared and the structure was characterized in solid (fourier transform‐ir and X‐ray analyses), in liquid (1H and 13C nmr titrations), and in the gas‐phase (fast atom bombardment (fab) and electron spray ionization (esi) ms). Two bis(2′‐hydroxyethyl) 2,6‐pyridinedicarboxylate molecules each with an included water molecule are bound together through hydrogen bonding to give a pseudo‐macrocycle in the solid state and in chloroform solution. The fab and esi mass spectra also suggested that ligand 1 forms a dimer in the gas‐phase. 相似文献
13.
A Methylthio‐Functionalized‐MOF Photocatalyst with High Performance for Visible‐Light‐Driven H2 Evolution
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Hui Chen Xian‐Bao Bu Yi‐Xuan Gao Hui Gao Prof. Yang Tian Prof. Gui‐Sheng Li Prof. Guo Wang Prof. Sheng‐Li Cao Prof. Chong‐Qing Wan Prof. Guo‐Cong Guo 《Angewandte Chemie (International ed. in English)》2018,57(31):9864-9869
Recently, the emergence of photoactive metal–organic frameworks (MOFs) has given great prospects for their applications as photocatalytic materials in visible‐light‐driven hydrogen evolution. Herein, a highly photoactive visible‐light‐driven material for H2 evolution was prepared by introducing methylthio terephthalate into a MOF lattice via solvent‐assisted ligand‐exchange method. Accordingly, a first methylthio‐functionalized porous MOF decorated with Pt co‐catalyst for efficient photocatalytic H2 evolution was achieved, which exhibited a high quantum yield (8.90 %) at 420 nm by use sacrificial triethanolamine. This hybrid material exhibited perfect H2 production rate as high as 3814.0 μmol g?1 h?1, which even is one order of magnitude higher than that of the state‐of‐the‐art Pt/MOF photocatalyst derived from aminoterephthalate. 相似文献
14.
Heduck Mah Kee Hyuk Chang Kee Dal Nam Hoh‐Gyu Hahn Su Yeoul Bae 《Journal of heterocyclic chemistry》2000,37(4):1003-1008
A new construction of dihydro‐1,4‐dioxin and a synthesis of 5,6‐dihydro‐2‐trifluoromethyl‐1,4‐dioxin‐3‐carboxanilides 22 through polymer‐bound activated ester are described. An intermediate β‐hydroxy ether 18 was prepared from the substitution reaction of α‐thio‐α‐chloro compound 8 with ethylene glycol followed by treatment with Raney Ni. Replacement of hydroxy by chlorine and then dehydrochlorination afforded trifluoromethyl dihydro‐1,4‐dioxin ester 15. The polymer‐bound trifluoromethyl dihydro‐1,4‐dioxin‐3‐carboxylic acid, 4‐hydroxy‐3‐nitrobenzophenone ester ( 21 ) was prepared through the reaction of polystyrene‐bound 4‐hydroxy‐3‐nitrobenzophenone ( 19 ) with the trifluoromethyl dihydro‐1,4‐dioxin‐3‐carbonyl chloride ( 20 ). Refluxing of 21 with substituted aniline in acetonitrile gave the corresponding carboxanilide 22. The reaction rate depended on the nucleophilicity of nitrogen of the aniline. 相似文献
15.
Bismetal Complexes of 5,20‐Bis(5‐formyl‐2‐pyrrolyl)‐[26]hexaphyrin(1.1.1.1.1.1) Exhibiting Strong Near‐Infrared Region Absorptions
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Hirotaka Mori Prof. Dr. Atsuhiro Osuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7007-7011
[26]Hexaphyrin(1.1.1.1.1.1) bearing two 5‐formyl‐2‐pyrrolyl groups at the 5‐ and 20‐positions was prepared by cross‐condensation of 5,10‐bis(pentafluorophenyl)‐substituted tripyrrane with 2,5‐diformylpyrrole as an effective binuclear metal‐coordinating ligand, owing to the two hemiporphyrin‐like NNNN pockets. In fact, metalation of this hexaphyrin with ZnII, CuII, and PdII salts proceed smoothly at room temperature to give the corresponding bismetal complexes that displayed remarkably redshifted absorption spectra reaching deep into near infrared region. These redshifted absorption bands are ascribed, through electrochemical investigations and DFT calculations, to two structural motifs: the N‐metalopyrrole substructure that elevates the HOMO level due to the electron‐donating property and the two coordinated metal ions that serve as Lewis acids to lower the LUMO level. 相似文献
16.
《Electrophoresis》2018,39(19):2460-2470
This study uses negative dielectrophoresis and AC electroosmosis as a driving mechanism and presents an electrically driven microconcentrator that concentrates the sample in the region exterior to the electrodes (termed as exterior‐electrode electrically driven microconcentrator in this paper). The proposed microconcentrator uses a 3‐D face‐to‐face electrode pair; the top electrode is a relatively large planar electrode, and the bottom electrode is formed with three to six long and thin electrodes connected into an open ring. The sample is brought to the vicinity of the open electrode at the bottom by electroosmotic flow; then, negative dielectrophoresis is used to push the sample away from the electrode and concentrate it in the region surrounded by the open ring electrode. Concentration using an exterior‐electrode electrically driven microconcentrator offers promise for convenient use in conjunction with relevant detection systems. The results indicate that for the proposed exterior‐electrode electrically driven microconcentrator, the optimal frequency is 100 kHz and the optimal voltage is 13 Vp‐p. The corner concentration process at the corners of the bottom open electrodes enables the multi‐corner electrodes to exhibit better concentration results than that exhibited by semicircular‐shaped electrodes. The concentration performance is most favorable when the shape of the open electrode at the bottom is a five‐vertex electrode, enabling a concentration enhancement factor of 55 times for a latex particle solution and 11 times for E. coli. The experimental results also demonstrate that the concentration phenomenon in this study is not induced by non‐specific adsorption and can be repeated multiple times. 相似文献
17.
Peiyi Wang Dr. Jun Hu Prof. Song Yang Prof. Baoan Song Prof. Qian Wang 《化学:亚洲杂志》2014,9(10):2880-2884
The mixing of a polyacid cross‐linker with a pyridinium‐functionalized anthracene amphiphile afforded a supramolecular hydrogel through a self‐assembly process that was primarily driven by π‐stacking and electrostatic interactions. 相似文献
18.
Visible‐Light‐Driven Intermolecular [2+2] Cycloadditions between Coumarin‐3‐Carboxylates and Acrylamide Analogs
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Prof. Dr. Qiang Liu Fu‐Ping Zhu Prof. Dr. Xiao‐Ling Jin Xiao‐Ju Wang Han Chen Prof. Dr. Li‐Zhu Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10326-10329
This paper reports a room temperature visible‐light‐driven protocol for the intermolecular [2+2] cycloadditions between coumarin‐3‐carboxylates and acrylamides analogs by an energy‐transfer process. Using an iridium complex FIrPic as a photosensitizer and a 3 W blue LED as a light source, an array of cyclobutabenzocypyranones were prepared in moderate to excellent yields. 相似文献
19.
By condensing 2‐aminobenzothiazole with 2‐hydroxy‐1‐naphthaldehyde, 2‐hydroxybenzaldehyde, 4‐methoxybenzaldehyde, 4‐hydroxybenzal‐dehyde, benzaldehyde and 4‐dimethylaminobenzaldehyde, and five Schiff bases Ia‐Ie are prepared. Also, two Schiff bases IIa and IIb are prepared by condensation of 2‐amino‐3‐hydroxypyridine with 2‐hydroxy‐1‐naphthaldehyde and 2‐hydroxybenzaldehyde. The 1H NMR, IR and UV/Vis spectra of these seven Schiff bases are investigated. The signals of the 1H NMR spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular structure. The UV/Vis absorption bands in ethanol are assigned to the corresponding electronic transitions and the electronic absorption spectra of Schiff bases Ib and IIb are studied in organic solvents of different polarities. The UV/Vis absorption spectra of 2‐amino‐3‐hydroxypyridine Schiff bases IIa and IIb are investigated in buffer solutions of different pH values containing 5% (v/v) methanol, and the results are utilized for the determination of pKa and ΔG* of the ionization of the phenolic OH‐groups. The fluorescence spectra of IIa and IIb are studied in organic solvents of different polarities. The obtained spectral results are confirmed by some molecular calculations using the atom super position and electron delocalization molecular orbital theory for the Schiff base IIb. 相似文献
20.
Ag/mesoporous black TiO2 nanotubes heterojunctions (Ag‐MBTHs) were fabricated through a surface hydrogenation, wet‐impregnation and photoreduction strategy. The as‐prepared Ag‐MBTHs possess a relatively high specific surface area of ≈85 m2 g?1 and an average pore size of ≈13.2 nm. The Ag‐MBTHs with a narrow band gap of ≈2.63 eV extend the photoresponse from UV to the visible‐light and near‐infrared (NIR) region. They exhibit excellent visible‐NIR‐driven photothermal catalytic and photocatalytic performance for complete conversion of nitro aromatic compounds (100 %) and mineralization of highly toxic phenol (100 %). The enhancement can be attributed to the mesoporous hollow structures increasing the light multi‐refraction, the Ti3+ in frameworks and the surface plasmon resonance (SPR) effect of plasmonic Ag nanoparticles favoring light‐harvesting and spatial separation of photogenerated electron–hole pairs, which is confirmed by transient fluorescence. The fabrication of this SPR‐enhanced visible‐NIR‐driven Ag‐MBTHs catalyst may provide new insights for designing other high‐performance heterojunctions as photocatalytic and photothermal catalytic nanomaterials. 相似文献