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61.
ngel Ramos Julio Santos Laura Abad Dionisio Bermejo Víctor J. Herrero Isabel Tanarro 《Journal of Raman spectroscopy : JRS》2009,40(9):1249-1256
An anomalous lineshape of stimulated Raman spectra obtained from the region very close to the nozzle of supersonic pulsed expansions of nitrogen is presented. High‐resolution Raman spectra of the Q branch of the fundamental vibration mode of N2 have been recorded from two different nitrogen expansions at T0 = 295 K and P0 = 1.5–3.5 bar, the lasers crossing the jet axis in the range z/D = 0.25–1.25, where D is the effective nozzle diameter. The combination of Doppler shifts and strong gradients of density and temperature in the near‐nozzle region yield an inhomogeneous broadening and a double peak structure of the recorded Raman line profiles. The comparison of the experimental results with the simulation of the Raman spectrum from this region provides valuable information about the near‐nozzle flow field. The lineshape described here is different from another reported previously in the literature, which is based on a depletion of the density of free molecules on the axis due to condensation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
62.
César Menor‐Salván Dr. Dra. Marta Ruiz‐Bermejo Marcelo I. Guzmán Dr. Susana Osuna‐Esteban Sabino Veintemillas‐Verdaguer Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(17):4411-4418
From urea to nucleobases : Freeze–thaw cycles in urea ( 1 ) solutions under methane/nitrogen atmospheres lead, with application of an energy source, to the synthesis of pyrimidines (mainly cytosine ( 2 ) and uracil ( 3 )), triazines (such as cyanuric acid ( 4 )), and adenine. This synthesis appears to be dependent on the atmosphere and the freezing conditions. At room temperature, hydantoin ( 5 ) is obtained. However, a freezing urea/water system subjected to an energy source under an inert atmosphere generates s‐triazines.
63.
Cámpora P Bermejo AM Tabernero MJ Fernández P 《Rapid communications in mass spectrometry : RCM》2006,20(8):1288-1292
An analytical method for the simultaneous determination of codeine, morphine and 6-acetylmorphine (6AM) in human oral fluid was developed. The method involves liquid-liquid extraction in Toxitubes A, derivatization with 99:1 (v/v) N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS), and gas chromatography/mass spectrometry with positive chemical ionization (GC/PCI-MS) determination. The detector response was linear over the concentration range 30-500 ng/mL with coefficients of correlation higher than 0.99. The precision was acceptable with coefficients of variation less than 7.5%. The limits of detection achieved were 0.7 ng/mL for codeine, 2.0 ng/mL for morphine, and 0.6 ng/mL for 6AM. The method proposed was applied to 80 oral fluid samples from opiates users, 98% of which were positive for the three analytes. Human oral fluid is a suitable biological fluid for the determination of opiates by GC/PCI-MS. 相似文献
64.
Numerous members of the Anthemideae tribe are important as cut flowers and ornamental crops, as well as being medicinal and aromatic plants, many of which produce essential oils used in folk and modern medicine and in the cosmetics and pharmaceutical industry. Essential oils generally have a broad spectrum of bioactivity, owing to the presence of several active ingredients that work through various modes of action. Due to their mode of extraction, mostly by distillation from aromatic plants, they contain a variety of volatile molecules such as terpenes, phenol-derived aromatic and aliphatic components. The large genus Artemisia L., from the tribe Anthemideae, comprises important medicinal plants which are currently the subject of phytochemical attention due to their biological and chemical diversity. Artemisia species, widespread throughout the world, are one of the most popular plants in Chinese traditional preparations and are frequently used for the treatment of diseases such as malaria, hepatitis, cancer, inflammation and infections by fungi, bacteria and viruses. Extensive studies of the chemical components of Artemisia have led to the identification of many compounds as well as essentials oils. This review summarizes some of the main reports on the chemistry and anti-infective activities of Artemisia. Li. essential oils from the data in the recent literature (2000-2011). 相似文献
65.
A. Zapardiel E. Bermejo J. A. Pérez M. Chicharro 《Analytical and bioanalytical chemistry》2000,367(5):461-466
The detection and determination of s-triazines, atrazine-desethyl and aziprotryne by cyclic voltammetry and an amperometric method using a metallic copper electrode and a glassy carbon electrode are described. The concentrations of atrazine-desethyl and aziprotryne in 0.1 M NaOH solutions were determined using the oxidation signal corresponding to the Cu(0)/Cu(I) redox process. The detection level calculated for these s-triazines were 0.3 and 0.5 μg/mL of analyte, respectively. The glassy carbon electrode was shown to give sensitive reduction response to aziprotryne in flow injection mode. No special activation was required for the glassy carbon electrode. A detection limit of 0.2 μg/mL (20 ng aziprotryne) was obtained for a sample loop of 0.1 mL at a fixed potential of –1.0 V (vs. Ag/AgCl) in 0.1 M HCl and a flow rate of ¶3.5 mL/min. Furthermore, the glassy carbon electrode showed stable response in such a system, and the relative standard deviation was only 2.7% using the same surface, and 6.3% using different surfaces. The method developed was applied to the determination of aziprotryne in environmental and tap water samples; using a prior solid-phase extraction step, aziprotryne concentrations lower than 1.0 ng/mL could be measured. 相似文献
66.
The First One‐Pot Synthesis of Metal–Organic Frameworks Functionalised with Two Transition‐Metal Complexes 下载免费PDF全文
Dr. Ana E. Platero‐Prats Dr. Antonio Bermejo Gómez Dr. Louise Samain Prof. Xiaodong Zou Prof. Belén Martín‐Matute 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):861-866
The synthesis of a metal–organic framework (UiO‐67) functionalised simultaneously with two different transition metal complexes (Ir and Pd or Rh) through a one‐pot procedure is reported for the first time. This has been achieved by an iterative modification of the synthesis parameters combined with characterisation of the resulting materials using different techniques, including X‐ray absorption spectroscopy (XAS). The method also allows the first synthesis of UiO‐67 with a very wide range of loadings (from 4 to 43 mol %) of an iridium complex ([IrCp*(bpydc)(Cl)Cl]2?; bpydc=2,2′‐bipyridine‐5,5′‐dicarboxylate, Cp*=pentamethylcyclopentadienyl) through a pre‐functionalisation methodology. 相似文献
67.
68.
69.
I. L. Eremenko M. A. Golubnichaya S. E. Nefedov A. A. Sidorov I. F. Golovaneva V. I. Burkov O. G. Ellert V. M. Novotortsev L. T. Ermenko A. Sousa M. R. Bermejo 《Russian Chemical Bulletin》1998,47(4):704-718
The reaction of NiCl2·6H2O with Me3CCOOH and KOH taken in a molar ratio of 1:2:2 in water afforded the nonanuclear antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which apparently contains NiII and NiIII atoms. The complex was isolated by extraction with CH2Cl2, benzene, or hexane. The reactions of this complex with pyridine bases (pyridine (Py), 3,4-lutidine (Lut), and nicorandil
(Nic)) gave the adducts L4Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH) (L=Py, Lut, or Nic, respectively). According to magnetic measurements, intramolecular ferromagnetic exchange interactions
in these adducts are complemented by intermolecular antiferromagnetic interactions. Pyrolysis of the pyridine adduct in air
or under an inert atmosphere in xylene yielded the antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which contains NiII atoms. The structures of all the complexes synthesized were established by X-ray diffraction analysis. The electronic absorption
spectra of these compounds are considered.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 725–738, April, 1998. 相似文献
70.
Elena Bermejo Alfonso Castieiras Douglas X. West 《Journal of Molecular Structure》2003,650(1-3):93-97
Condensation of thiosemicarbazide or N(4)-ethylthiosemicarbazide with 1,2,8,9-tetraphenyl-3,7-diazanona-1,9-dione in the presence of copper(II) acetate in 96% ethanol leads to Δ6-5,6-diphenyl-5-methoxy-1,2,4-triazacyclohexene-3-thione, C16H15N3OS, or Δ6-4-methyl-5,6-diphenyl-5-ethoxy-1,2,4-triazacyclohexene-3-thione, C18H19N3OS. For C16H15N3OS the crystal data are monoclinic, P21/c, a=9.7780(7), b=8.5120(3), c=18.2210(13) Å, β=100.958(3)°, V=1488.89(16) Å3, and Z=4 in agreement with an earlier report. For C18H19N3OS the crystal data are orthorhombic, P212121, a=8.6940(3), b=12.9946(3), c=15.5139(5) Å, V=1752.68(9) Å3, and Z=4. 相似文献