共查询到20条相似文献,搜索用时 15 毫秒
1.
Merlin C. E. Bandeira Joseph A. Crayston Norberto S. Gonçalves Lúcia K. Noda Andrew Glidle César V. Franco 《Journal of Solid State Electrochemistry》2007,11(2):231-239
The electropolymerization of trans-[RuCl2(vpy)4] (vpy=4-vinylpyridine) on Au or Pt electrodes was studied by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM) technique, and Raman spectroscopy. Cyclic voltammetry of the monomer at a microelectrode shows the typical Ru(III/II) and Ru(IV/III) waves, together with the vinyl reduction waves at −1.5 and −2.45 V and adsorption wave at −0.8 V. Electrodeposition on EQCM technique performed under potential cycling between −0.9 and −2.0 V revealed that the polymerization proceeded well in advance of the vinyl reduction waves. At potentials more positive than −0.9 V, soluble oligomers were deposited irreversibly on the electrode during the oxidative sweep. The film also showed reversible mass changes due to the oxidation and accompanying ingress of charge-balancing anions and solvent into the film. In contrast, potentiostatic growth of the polymer at −1.6 V was slower because the oligomeric material was lost completely from the electrode. Unreacted vinyl groups were detected by in situ Raman spectroscopy for films grown at −0.7, −0.9, and −1.6 V but were absent when the polymerization was carried out at −2.9 V vs Ag/Ag+. 相似文献
2.
A new synthetic approach to 4E,7Z-tridecadien-1-ylacetate, a component of the Phthorimaea opercucella (Zeller) potato moth sex pheromone, was developed using a highly stereoselective Claisen rearrangement and Wittig reaction.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 235–236, May–June, 2007. 相似文献
3.
M. Madesclaire V. P. Zaitsev J. V. Zaitseva S. Kh. Sharipova 《Chemistry of Heterocyclic Compounds》2007,43(10):1325-1332
A synthesis is reported for (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones and (1′R,4R)-and (1′S,4S)-4-[hydroxy(4-nitrophenyl)methyl]oxazolidin-2-ones from (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols. The effect of the experimental conditions on the formation of these compounds
was studied.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1562–1570, October, 2007. 相似文献
4.
Summary. An efficient direct conversion of THP ethers into the corresponding acetates was achieved with acetic anhydride in the presence of CuSO4 · 5H2O as an available and green catalyst in high yields. 相似文献
5.
I. A. Vakulenko V. A. Startseva L. E. Nikitina N. P. Artemova L. L. Frolova A. V. Kuchin 《Chemistry of Natural Compounds》2005,41(6):686-688
The reaction of cis-verbenol with thiols in the presence of ZnCl2 occurred stereospecifically with substitution of the hydroxyl by a sulfide.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 565–567, November–December, 2005. 相似文献
6.
The new norditerpenoid alkaloid shawurensine in addition to β-sitosterol and the known alkaloids elatin, delbrulin, and methyllycaconitine were isolated from Delphinium shawurense. A structure for shawurensine was proposed based on spectral data.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 248–250, May–June, 2007. 相似文献
7.
E. Tomaszewicz 《Journal of Thermal Analysis and Calorimetry》2008,93(3):711-715
Three new compounds MPr2W2O10 (M=Mn, Co, Cd) were prepared by the solid-state reaction. They are isostructural and crystallize in the orthorhombic system.
MPr2W2O10 (M=Mn or Co) melt incongruently above 1150°C and the solid product of melting is Pr2W2O9. The CdPr2W2O9 compound starts decomposing in the solid-state at 1156°C to Pr2W2O9 and CdO. 相似文献
8.
A structure and kinetic stability study on some complexes with the general formula MN5, where M are the alkali-metal atoms, Li, Na, K, and Rb, has been carried by using hybrid density functional methods. Complex B (C2v) with two points of attachment to the N5 ring is the most energetically favored for all metals considered here. Pyramidal structures A (C5v) are kinetically unstable and they rapidly rearrange to the most stable planar structures B. At the QCISD(T)/6-311 + G*//B3LYP/6-311 + G* + ZPE (B3LYP/6-311 + G*) level, the decomposition barrier heights of LiN5-B, NaN5–B, KN5-B, and RbN5-B are predicted to be 19.9, 22.0, 22.5, and 23.0 kcal/mol, respectively. In addition, the rate constants of the decomposition reaction MN5-B MN3 + N2 (M + Li, Na, K, and Rb) are also predicted using conventional transition state theory and canonical variational transition state theory, respectively. 相似文献
9.
M. Arshad A. H. Qureshi K. Masud N. K. Qazi 《Journal of Thermal Analysis and Calorimetry》2007,89(2):595-600
The production of bulk high T
c superconducting phase (2223) by EDTA-gel (ethylenediaminetetraacetic acid) techniques has been investigated. It is shown
that close control of pH is necessary for the production of a well-complexed precursor which allows subsequent decomposition
in two stages at 300 and 800°C. The problem of carbonate formation was investigated experimentally and solved. Precursors
are characterised by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) and the sintering behaviour
was monitored by dilatometry. At least three different phases Bi2Sr2Cax−1CuxO8+y (BSCCO); where x=1, 2, 3 were identified within superconducting pellets using XRD, named as Bi2Sr2CuO7 (2201), Bi2Sr2CaCu2O9 (2212) and Bi2Sr2Ca3O10 (2223). The superconducting properties of the sintered samples were studied by vibrating sample magnetometer (VSM). Transition
to a superconducting state around 80 K appeared in samples (sintered at 845°C) containing the Bi2Sr2Ca1Cu2Oy (2212) phase. Liquid phase sintering of the samples aided the formation of Bi2Sr2Ca2Cu3Ox (2223) phase at high temperature (860°C), which showed a superconducting transition temperature of 108 K. 相似文献
10.
Mircho Georgiev Tatiana Popova Zhorro S. Nickolov Nikolay Goutev Georgi Georgiev Hiroatsu Matsuura 《Central European Journal of Chemistry》2004,2(4):617-626
The hypothesis that the degree of hydration of poly(oxyethylene) (POE) in aqueous solution depends on the mole ratio of water
molecules to ether oxygen atoms in the molecule has been verified by studying the isotropic Raman spectra in the O−H stretching
region for four short-chain POEs (C 1E
n
C 1 withn=1−4). Excellent coincidence of the O−H stretching Raman band for all four POEs studied in the range of mole ratio H2O/O
ether
from 25 to 0.6 was observed, thus confirming the assumption stated above. A conclusion that all ether oxygen atoms in the
POE molecule participate in hydrogen bonding with water molecules has been made. 相似文献
11.
The geometries of N,N′-diphenylbenzene-1,4-diamine (DPPD), N-phenyl-N′-(1-phenylethyl)benzene-1,4-diamine (SPPD), N-(4-methylpentan-2-yl)-N′-phenylbenzene-1,4-diamine (6PPD), N-propan-2-yl-N′-phenylbenzene-1,4-diamine (IPPD), N-(2-methoxybenzyl)-N′-phenylbenzene-1,4-diamine (MBPPD), and N-phenyl-N′-(2-phenylpropan-2-yl)benzene-1,4-diamine (CPPD) as well as of their dehydrogenation products were optimized by the semiempirical
AM1 method. The results support the idea of stable NB=CX structures formation during the consecutive dehydrogenation of SPPD, 6PPD, IPPD, and MBPPD antioxidants. The biradicals formed
during the second step of dehydrogenation of substituted phenylenediamines might be important for their antioxidant effectiveness.
Dedicated to Professor Vladimír Kvasnička, DrSc., in honour of his 65th birthday 相似文献
12.
Shu Yang Xiao-dong Yang Jing-feng Zhao Yang Jin Hong-bin Zhang Liang Li 《Chemistry of Natural Compounds》2008,44(3):334-336
A new C19-diterpenoid alkaloid, habaenine C (1), together with the two known compounds vilmorrianine C and crassicauline A, were isolated from Aconitum habaense. The structure of the new compound was elucidated on the basis of spectral analysis, including 2D NMR spectroscopy.
Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 265–266, May–June, 2008. 相似文献
13.
Jian Chen Zuo-Ming Nie Zheng-Bing Lü Cheng-Gang Zhu Cheng-Zhi Xu Yong-Feng Jin Xiang-Fu Wu Yao-Zhou Zhang 《Applied biochemistry and biotechnology》2007,141(1):149-159
Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) acts on many different kinds of cells, including monocytes,
macrophages, granulocytes, eosinophils, and multipotential stem cells. To explore further explore pharmaceutical action, we
expressed hGM-CSF by the Bombyx mori nucleopolyhedrovirus expression system in silkworm pupae. However, purifying recombinant proteins from silkworm pupae on
a large scale has been a big challenge. To establish purification methods suitable for mass production, we tried two crude
preparation methods: (NH4)2SO4 fractional precipitation and isoelectric precipitation with a combination of gel filtration andion-exchange chromatography.
The isoelectric precipitation method was found to be more efficient. With this method, we eventually obtained approx 11.7
mg of 95% pure product from 1000 g of infected silkworm pupae. The recovery of purified protein was greatly increased, by
approx 40%, compared with the other method. The biologic activity of this protein was determined up to 9.0×106 colony-forming units/mg in the final purified product. 相似文献
14.
J. Meuche-Albeny P. Rathelot M. P. Crozet P. Vanelle 《Chemistry of Heterocyclic Compounds》2003,39(8):989-997
5-Chloromethyl-6-nitrobenzo[1,3]dioxole has been shown to react with 2-nitropropane anion to give C-alkylation by an S
RN1 mechanism. The reaction was extended to various aliphatic, cyclic, and heterocyclic nitronate anions, leading to a new series of nitrobenzo[1,3]dioxole derivatives. 相似文献
15.
A. H. Qureshi M. Arshad S. K. Durrani H. Waqas 《Journal of Thermal Analysis and Calorimetry》2008,94(1):175-180
Sol-gel process was employed to synthesize the Pb-BSCCO system having general composition Bi2−xPbxSr2Ca2Cu3O10−δ, where x=0.2, 0.4 and 0.8. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), dilatometry and vibrating sample
magnetometer (VSM) were employed to study the materials produced at different stages. Two-stage heating firstly at 300 and
then 800°C was adopted in order to avoid the burning of the materials and formation of carbonates. The carbonate formation
was avoided by heating the materials firstly at 300°C for 2 h and without intermediate cooling moved to the furnace having
temperature 800°C and hold for 2 h. The sintering behaviour of samples was studied by dilatometry and the results revealed
that the sample having x=0.4 was stabled up to a temperature of 700°C while samples having x=0.2 and 0.8 to a temperature of 625°C. The maximum shrinkage was observed at 850°C in all the samples. On the basis of dilatometry
results, the samples were sintered at 845°C for 60 h to observe the superconducting phases. The highest volume fraction of
high superconducting phase (2223) was noticed in the sample containing x=0.4 having onset T
c=110 K. 相似文献
16.
The dried and aerial part of Linum mucronatum ssp. mucronatum was analyzed by gas chromatography-mass spectrometry (GC-MS). Two aryltetralin lignans, podophylloyoxin, 6-methoxypodophylloyoxin, and β-peltatin, were identified. This is the first report of the analysis of L. mucronatum ssp. mucronatum.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 24–25, January–February, 2005. 相似文献
17.
Horia Petride Constantin Drãghici Cristina Florea Aurica Petride 《Central European Journal of Chemistry》2004,2(2):302-322
N-Benzylmorpholine,-piperidine, and-pyrrolidine (1A-C, resp.) are oxidised by RuO4 (generated in situ) at both endocyclic and exocyclic (benzylic) N—α-methylene positions to afford lactams (and dioxo-derivatives) and benzaldehyde (and benzoyl derivatives), respectively.
The N-oxides of 1A-C, formed by a minor side reaction, are not involved as intermediates. Control experiments showed the transient formation of
endo- and exocyclic iminium cations trapped with NaCN as the corresponding nitriles. The proposed course of the RuO4-mediated oxidation of 1A-C involves the consecutive steps 1⇒iminium cations+cyclic enamine⇒oxidation products. The endocyclic/exocyclic regioselectivity of the oxidation reaction lies
between 0.8 (for 1A) and 2.1 (for 1B). The amine cation radical and the N-α-C· carbon-centered radical seem not to be involved. 相似文献
18.
Vera L. M. Silva Artur M. S. Silva Diana C. G. A. Pinto Nadine Jagerovic Luis F. Callado José A. S. Cavaleiro José Elguero 《Monatshefte für Chemie / Chemical Monthly》2007,138(8):797-811
Summary. The syntheses of several new 3- and 5-(4-chloro-2-hydroxyphenyl)-5- and -3-(2,4-dichlorophenyl)-1-alkylpyrazoles are reported.
These syntheses started from simple chlorophenols, 2,4-dichlorobenzaldehyde or ethyl 2,4-dichlorobenzoate in order to prepare
pyrazoles bearing three and four chloro substituents in certain positions. The affinity of these compounds towards the CB
1 type cannabinoids receptors was then evaluated in human brain tissues (frontal cortex). The results showed that some of the
compounds exhibit affinity towards this kind of receptors in the micromolar range. 相似文献
19.
Huang Yun Cui Lijian Zhan Wenhong Dou Yuhong Wang Yongli Wang Qiang Zhao Ding 《Chemistry of Natural Compounds》2007,43(6):672-677
A novel steroidal saponin, along with 12 known steroidal compounds, was isolated from the rhizomes of Paris polyphylla var. chinensis. Spectral data, including two-dimensional NMR, showed that the structure of the novel saponin was 3β,21-dihydroxypregnane-5-en-20S-(22,16)-lactone-1-O-α-L-rhamnopyranosyl(1→2)-[β-D-xylopyranosyl(1→3)]-β-D-glucopyranoside. The isolated steroidal compounds were evaluated for their cytotoxic activity on human gastric cancer cell
line HepG2, SGC7901, BxPC3. Diosgenin-3-O-α-L-rhamnopyranosyl(1→2)[α-L-rabinofuranosyl(1→4)]-β-D-glucopyranoside exhibited the most potent cytotoxic activity among the isolated steroids.
Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 556–560, November–December, 2007. 相似文献
20.
Dan Xie Zhigang Zhang Tianling Ren Litian Liu 《Journal of Sol-Gel Science and Technology》2007,42(3):271-276
Bi-layered ferroelectric Bi3TiTaO9 (BTT) thin films with different thickness (ranging from 100 to 400 nm) were successfully fabricated on Pt(111)/TiO2/SiO2/(100)Si substrates using chemical solution deposition (CSD) technique at different annealing temperatures. The c-axis orientation of the films was affected by film thickness and process temperature. The thinner the film and the higher
the process temperature, the higher the c-axis orientation. With the increase of film thickness, the stress decreased but the film roughness increased, which led to
the decrease of c-axis orientation of films. BTT films annealed at 800°C were found to have much improved remament polarization (P
r
) than that of films annealed at 650 and 750°C. The P
r
and coercive field (E
c
) values were measured to be 2 μC/cm2 and 100 kV/cm, respectively. BTT films showed well-defined ferroelectric properties with grain size larger than 100 nm. 相似文献