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1.
L. O. Khafizova L. R. Yakupova R. A. Tuktarova V. A. D’yakonov L. M. Khalilov A. G. Ibragimov U. M. Dzhemilev 《Russian Journal of Organic Chemistry》2008,44(9):1311-1315
[4π + 2π]-Cycloaddition of substituted alumina-and magnesacyclopenta-2,4-dienes with such dienophiles as maleic anhydride, N-methylmaleimide, 1,4-benzoquinone, and 1,4-naphthoquinone resulted in the formation of the corresponding fused alumina-and magnesanorbornenes whose hydrolysis gave isobenzofuran, isoindole, naphthalene, and anthracene derivatives in high yields. 相似文献
2.
Reactions of pyridine N-oxide with ethylenediamine and o- and p-phenylenediamines in the presence of p-toluenesulfonyl chloride in alkaline medium lead to the formation of the corresponding N,N′-bis-(p-tolylsulfonyl)-N,N′-bis(pyridin-2-yl)diamines as a result of reductive acylamination. 相似文献
3.
Hamzeh Eyni Mansour Jahangiri Farhoush Kiani Hasan Tahermansouri 《Journal of solution chemistry》2018,47(6):1079-1095
In this work we investigate the thermodynamic properties and pKa value of lamivudine and pefloxacin drugs, in aqueous solutions, by ab initio and density functional theory (DFT) methods at different temperatures. Molecular structures and solute–solvent effects of the anions, cations, and neutral molecules of lamivudine and pefloxacin were studied by the polarizable continuum model (PCM). The calculation was done at the DFT-B3LYP/6-31+G(d) level of theory using Tomasi’s method to analyze the formation of intermolecular hydrogen bonds (IHB) in aqueous solution. The pKa1 values of lamivudine and pKa2 values of pefloxacin increase with temperature increase. In contrast, the pKa1 values of pefloxacin decrease when the temperature increases. Further, the thermodynamic properties of the ionization processes (?H, ?S and ?G) of the drugs in aqueous solution were determined and discussed. The results of this work are in good agreement with the literature data at 298.15 K. 相似文献
4.
M. L. Antipova D. L. Gurina E. G. Odintsova V. E. Petrenko 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(4):708-714
The solvate structures formed by the ortho-, meta-, and para-isomers of hydroxybenzoic acid (o-HBA, m-HBA, and p-HBA) with a polar co-solvent (methanol at a concentration of 0.030 and 0.035 mole fractions) in supercritical carbon dioxide at a constant density of 0.7 g/cm3 and temperatures of 318 and 328 K have been studied by the classic molecular dynamics. It has been determined that a stable hydrogen-bonded complex with the co-solvent forms via the hydrogen of the carboxyl group for all isomers. The probability of this complex existence is high at all temperatures and concentrations. In the o-HBA molecule, the other functional groups are engaged in the intramolecular hydrogen bond, but not involved in interactions with methanol. It has been found that m-HBA and p-HBA can be involved in hydrogen bonds with methanol via hydroxyl hydrogen and oxygen atoms; they are characterized by the presence of one more co-solvent molecule (rarely, two molecules) in their solvation shell and intermittent formations/breakages of hydrogen bonds via other functional groups. These bonds are far less stable, and their formation is sensitive to change of temperature and co-solvent concentration. It has been concluded that the degree of selective solvation of m-HBA and p-HBA by co-solvent molecules is approximately the same, but the rate of structural rearrangements in the nearest environment of m-HBA is higher than that of p-HBA. 相似文献
5.
Rouhollah Heydari Mohammad Hosseini Reza Rezaeepour 《Journal of the Iranian Chemical Society》2017,14(8):1691-1698
In this study, a new device for semi-automated salt-assisted liquid–liquid extraction was designed and coupled with high-performance liquid chromatography (HPLC) to determine three aromatic hydrocarbons in aqueous samples. In order to evaluate the performance of the designed device, three aromatic hydrocarbons including 2-naphthol, naphthalene and anthracene were selected as model analytes. Sample solution, extraction solvent and salt solution using separate channels were transferred to a sample holder, respectively. These three components were mixed using a magnetic stirrer. After stirrer stopping, the aqueous and organic phases were separated and organic layer transferred to the injection loop of HPLC system. Optimization process was achieved using response surface methodology by Design-Expert software. A central composite design was used to optimize the main parameters including pH (A), stirrer time (B), organic solvent volume (C) and salt concentration (D). The limit of quantitation for 2-naphthol, naphthalene and anthracene was 15.0, 25.0 and 1.0 ng mL?1, respectively. Under the optimum conditions, obtained recoveries for three analytes were in the range of 76.0–96.2% with relative standard deviation less than 8.2%. The salt-assisted liquid–liquid extraction method using the proposed device has been successfully used for the analysis of real samples containing studied analytes in various matrices. 相似文献
6.
D. V. Ludin A. V. Markin S. D. Zaitsev S. E. Shuvalov Yu. L. Kuznetsova 《Russian Journal of Applied Chemistry》2016,89(6):921-925
Thermal behavior of polymers [poly(methyl methacrylate), poly(methyl acrylate), polystyrene] prepared in the presence of tri-n-butylboron and a series of p-quinones was studied. The heat resistance of the polymers increases with an increase in the inhibition constant of the p-quinone taken for the synthesis. The enhancement of the heat resistance of the polymer is due to a decrease in the amount of weak bonds and to the formation of associates. 相似文献
7.
Yin-Tao Li Quan-Ping Zhang Feng Xiao Yuan-Lin Zhou 《Russian Journal of General Chemistry》2016,86(2):356-359
Three p-phenylenediamine antioxidants (p-phenylenediamine-N,N,N′,N′-tetrapropionic acid tetramethyl ester, p-phenylenediamine-N,N,N′-tripropionic acid trimethyl ester, and p-phenylenediamine-N, N′-dipropionic acid dimethyl ester) were successfully synthesized via atom-economic aza-Michael addition of pphenylenediamine to methyl acrylate p-romoted by graphene oxide in water. The synthesized compounds were characterized by NMR, ESI-MS spectra, and elemental analyses. The effects of the solvent and graphene oxide on the reaction were investigated. 相似文献
8.
Kamal I. Aly Amr H. Moustafa Essam K. Ahmed Hany M. Abd El-lateef Mohamed Gamal Mohamed Sahar M. Mohamed 《高分子科学》2018,36(7):835-847
Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer 1a with different kinds of diacid chlorides (including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4′-azodibenzoyl, 3,3′-azodibenzoyl, p-phenylene diacryloyl) in the presence of LiCl and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy (including 1H-NMR and 13C-NMR) and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis (TGA), wide-angle X-ray diffraction analysis (WAXD) and scanning electron microscopy (SEM). Also, the corrosion inhibition behavior of selected examples of polyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol·L?1 HCl was studied using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency (P, %) was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm. 相似文献
9.
K. V. Turov T. K. Vinogradova B. S. Drach 《Russian Journal of General Chemistry》2008,78(11):2132-2136
Accessible 2,2-dichloro-1-p-tolylsulfonylethenyl isothiocyanate reacted with hydrazine hydrate to give 5-chloro-2-hydrazino-4-p-tolylsulfonyl-1,3-thiazole whose reactions with thiols and amines followed a complicated pattern. Treatment of 5-chloro-2-hydrazino-4-p-tolylsulfonyl-1,3-thiazole with acetylacetone led to the formation of previously unknown 5-chloro-2-(3,5-dimethyl-1H-pyrazol-1-yl)-4-p-tolylsulfonyl-1,3-thiazole which reacted with O-, S-, and N-centered nucleophiles at the C5 atom with high regioselectivity. 相似文献
10.
Two pairs of amino-acid functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives, namely, poly(N-(tert-butoxycarbonyl)-L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Boc-Met) and poly(N-(tert-butoxycarbonyl)-D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Boc-Met); poly(L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Met) and poly(D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Met) were synthesized via chemical oxidative polymerization of corresponding monomers. The structural characterization, spectroscopic properties and thermal stability of these monomers and polymers were systematically explored by FTIR spectra, Raman spectra, XRD spectra, UV-Vis spectra and thermogravimetric analysis. As chiral electrode materials, these polymers were employed to successfully recognize 3,4-dihydroxyphenylalanine (DOPA) enantiomers by cyclic voltammetry (CV) in sulphuric acid solution. The measurement results reveal that the tendency was hetero-chiral interaction between L-PEDOT-Met/PVA/GCE and D-DOPA, D-PEDOT-Met/PVA/GCE and L-DOPA, respectively. Also, the mechanism of chiral discrimination was discussed. All the results implied that the combination of electrochemical molecular recognition technology and chiral PEDOT materials can be a promising approach for chiral recognition and may open new opportunities for facile, biocompatible, sensitive and robust chiral assays in biochemical applications. 相似文献
11.
Jingjing Shi Imran Murtaza Shan Shao Xiaosi Zhu Yang Zhao Mengmeng Zhu Osamu Goto Hong Meng 《中国科学:化学(英文版)》2017,60(1):90-98
A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole) (P(t-EDOT-mPy)) and poly(5,5′,5′′,5′′′-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine)) (P(t-EDOT-Th)) are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th, respectively. Compared with the linear 2D structured poly(thiophene) (E g=2.2 eV) and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene) (E g=1.7 eV), P(t-EDOT-Th) (E g=1.62 eV) has the lowest band gap. Hence, we speculate that the band gaps of the two polymers, having 3D structures, are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers, thiophene and 1-methyl-1H-pyrrole. The results indicated that P(t-EDOT-Th) thin films are more stable and show higher transmittance amid two polymers, which may find their utilization in organic optoelectronics. 相似文献
12.
Mono-, di-, and tetrasubstituted derivatives of p-tert-butylthiacalix[4]arene containing tert-butylcarbamate, tert-butylcarbonate, and tert-butyl fragments have been prepared for the first time. Depending on the reaction conditions (reagents ratio, temperature, and the presence of a base), the interaction of the monoamine derivative of p-tert-butylthiacalix[4]arene with di-tert-butyl dicarbonate can lead to the formation of mono-, di-, and tetrasubstituted products. 相似文献
13.
p-Phenylenediamine was oxidized with p-benzoquinone in the aqueous solutions of methanesulfonic acid (MSA). The conductivity of the products increased with increasing concentration of MSA from 1.5?×?10?12 S cm?1 in 0.1 M MSA up to 3.4?×?10?4 S cm?1 in 5 M MSA. The low-molecular-weight products are basically composed of one p-benzoquinone and two p-phenylenediamine molecules. Their molecular structure is discussed on the basis of mass, Fourier-transform infrared, Raman, NMR and electron paramagnetic resonance (EPR) spectroscopies. The formation of 2,5-di(p-phenylenediamine)-p-benzoquinone protonated with methanesulfonic acid best complies with the information provided by spectroscopic techniques. Its conversion to hydroquinone tautomer explains the formation of unpaired spins observed by EPR and their potential contribution to the conduction. 相似文献
14.
O. V. Andreeva B. F. Garifullin A. T. Gubaidullin V. A. Al’fonsov V. E. Kataev D. V. Ryzhikov 《Journal of Structural Chemistry》2007,48(3):540-546
Crystalline inclusion complexes of diterpenoid isosteviol (ent-16-ketobeyeran-19-oic acid) with individual benzene, o-, m-, p-xylenes, ethylbenzene, isopropylbenzene, o-and m-nitoranilins, benzaldehyde, styrene and naphthalene are obtained and characterized by single crystal X-ray diffraction. As determined by GC and 1H NMR spectroscopy, isosteviol selectively includes toluene from the equimolar benzene-toluene mixture, o-xylene from a commercial mixture of xylenes, o-and m-nitroanilins from their mixture with p-nitroanilin, and also styrene from styrene-ethylbenzene and styrene-isopropylbenzene mixtures thus yielding crystalline inclusion complexes. 相似文献
15.
Juan Du Zhie Zhou Xueqing Zhang Shuang Wu Jianhua Xiong Wenjun Wang Qiushui Luo 《Journal of Cluster Science》2017,28(6):3149-3158
Biosynthesis of gold nanoparticles (GNPs) by flavonoids from Lilium casa blanca has been developed. Several parameters such as pH, reaction temperature, reaction time and concentration of flavonoids were explored to control the formation of the GNPs. The synthesized GNPs were characterized by UV–Vis spectroscopy, transmission electron microscopy and X-ray diffraction. Stability and catalytic activity of the synthesized GNPs were also discussed. The results showed that the synthesized GNPs were in spherical, about 2.6 nm, with a face centered cubic structure. Synthesized GNPs showed good catalytic activity in the reduction of p-nitrophenol (p-NP) to p-aminphenol (p-AP). This method for synthesis of GNPs is simple, economic, nontoxic and efficient. 相似文献
16.
A. S. Shkvarin Yu. M. Yarmoshenko N. A. Skorikov A. A. Titov A. N. Titov 《Journal of Structural Chemistry》2011,52(1):65-69
The Cu3p and Cu2p resonance photoelectron spectra of the valence bands and core levels as well as Ti and CuL 2,3 absorption spectra for monocrystals 1T-Cu x TiSe2 were studied. The valence spectra obtained at Cu3p and Cu2p resonance drastically differ from each other. For Cu 3p-3d resonance, there are several bands corresponding to different channels of excited state decay. Spectra of the valence bands at Cu 2p-3d resonance are virtually identical to the spectra of pure TiSe2. As follows from the absorption spectra, titanium atoms have the oxidation state 4+, whereas copper atoms are close to the free ion state. 相似文献
17.
P. I. Fedorov T. P. Fedorova V. P. Sheverdov G. P. Pavlov A. V. Eremkin 《Russian Journal of Organic Chemistry》2016,52(6):806-812
Precursors to terpene alcohols of the o- and p-menthane series (o-cimen-7-ol and o- and p-cimen-9-ols) were synthesized, and their reduction with lithium in ethylenediamine was studied. The reduction of o- and p-cimen-9-ols in the presence of isopropyl alcohol selectively afforded the corresponding 1,4-dihydro derivatives. Under analogous conditions, o-cimen-7-ol was converted into a mixture of unsaturated hydrocarbons. The reduction with lithium in ethylenediamine in the absence of isopropyl alcohol in all cases gave mixtures of menthene alcohols. 相似文献
18.
T. A. Babushkina S. I. Kuznetsov V. M. Burbelo T. P. Klimova M. P. Tsyurupa V. A. Davankov 《Polymer Science Series A》2017,59(5):635-639
Using nuclear quadrupole resonance spectroscopy, it has been found that chloroform and dichloroethane absorbed by microporous hypercrosslinked polystyrene retain the capacity of the crystalline structure formation in small free spaces of the network on cooling, whereas p-dichlorobenzene demonstrates the complete loss of the capacity of crystallization. 相似文献
19.
S. P. Wang L. J. Xu Z. H. Gao R. F. Wang 《Russian Journal of Coordination Chemistry》2010,36(10):786-792
A terbium p-methyl benzoate complex with 1,10-phenanthroline, [Tb(p-MBA)3(Phen)]2 (p-MBA = p-methyl benzoate and Phen = 1,10-phenanthroline), has been prepared and structurally characterized by X-ray diffraction. It crystallizes in triclinic system, space group P \(\bar 1\) with a = 12.8064(12), b = 13.3589(12), c = 19.8277(19) Å, α = 91.668(2)°, β = 97.775(2)°, γ = 106.312(2)°, C72H58N4O12Tb2, M r = 1489.06, V = 3217.6(5) Å3, Z = 2, ρ c = 1.537 g/cm3, μ(MoK α) = 2.246 mm?1, F(000) = 1488, the final R = 0.0622 and wR = 0.0962 for 14128 independent reflections with R int = 0.0843. It consists of two types of crystallographically independent dimeric molecules [Tb(p-MBA)3(Phen)]2 noted as [Tb-1] and [Tb-2]. In the dimeric molecule [Tb-1], each Tb(III) is eight-coordinated with one Phen molecule, two bridging carboxylate groups, and two bidentate chelating carboxylate groups, while in [Tb-2] each Tb(III) is eight-coordinated with one Phen molecule, four bridging carboxylate groups, and one bidentate chelating carboxylate group. The title complex shows intense green luminescence under UV light at room temperature. 相似文献
20.
Z. V. Akhmetzyanova G. R. Allakhverdili A. S. Ovsyannikov S. E. Solovieva A. I. Konovalov 《Doklady Chemistry》2018,479(1):31-35
The paper describes the first synthesis of molecular tectons, a series of ligands based on thiacalix[4]arenes in the 1,3-alternate stereoisomeric form containing photoswitchable azo groups in the side chain and carboxyl groups as potential binding sites for the synthesis of photoswitchable complexes and coordination polymers. In the case of p-tert-butylcalixarenes, the convergent approach is preferred. 相似文献