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Grošev VM Foretić B Gamulin O 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1376-1379
Pyrimidinium aldoximes are administered intravenously in cases of acute organophosphate poisoning. Since questions regarding their morphology and active conformation in the solution are still open, an effort was made to establish correspondence between their crystal state conformers and vibrational spectra, thus facilitating the future work on the assignment of bands in solution. Normal coordinate analysis including the potential energy distribution for all modes was performed for 1-methyl-pyridinium-2-aldoxime (PAM2AN) and 1-methyl-pyridinium-4-aldoxime (PAM4AN) cations (charge=+e, spin=0). Positions of infrared and Raman bands of corresponding chloride salts agree rather well with predicted values, except for modes taking part in hydrogen bonding to anions. The strength of hydrogen bonding is estimated to be of medium strength in both salts, the bonding in PAM2AN being stronger. The calculated and observed values of the characteristic stretching modes for the aldoxime moiety have been in accordance with the stronger acidity of PAM2AN structural isomer. 相似文献
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A series of novel mono-1,2,3-triazole and bis-1,2,3-triazole acyclonucleoside analogues of 9-(4-hydroxybutyl)guanine was prepared via copper(I)-catalyzed 1,3-dipolar cycloaddition of N-9 propargylpurine, N-1-propargylpyrimidines/as-triazine with the azido-pseudo-sugar 4-azidobutylacetate under solvent-free microwave conditions, followed by treatment with K(2)CO(3)/MeOH, or NH(3)/MeOH. All compounds studied in this work were screened for their antiviral activities [against human rhinovirus (HRV) and hepatitis C virus (HCV)] and antibacterial activities against a series of Gram positive and negative bacteria. 相似文献
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Moha Boutat 《Bulletin des Sciences Mathématiques》2009,133(4):335-347
A result of F. Berteloot and G. Patrizio [F. Berteloot, G. Patrizio, A cartan theorem for proper holomorphic mappings of complete circular domains, Adv. Math. 153 (2000) 342-352] states that if f is a proper holomorphic map between two bounded complete circular domains Ω1 and Ω2 in Cn+1 (n?1), such that f−1{0}={0} and such that the principal part fp of the Taylor expansions of f at the origine is nondegenerated i.e. fp−1{0}={0}, then f=fp.Here, we give a partial extension of this result to the case where f is a nondegenerated proper holomorphic map between a quasi-circular domain Ω1 and a complete circular domain Ω2, which are pseudo-convex but not necessarily bounded.We show that if f and its principal part fp are nondegenerated at the origine, then fp−1(Ω2)=Ω1. 相似文献
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Bellete B Rabérin H Flori P El Akssi S Tran Manh Sung R Taourirte M Hafid J 《Natural product research》2012,26(18):1692-1696
The aim of the study was to determine the antifungal effects of the essential oil of Thymus broussonetii Boiss (EOT), an endemic plant in Morocco against Candida albicans, Aspergillus fumigatus and the dermatophytes. EOT was extracted by steam distillation. A suspension of up to 500?μL of C. albicans at a concentration of 10??CFU?mL?1 and A. fumigatus at a concentration of 101??spores?mL?1 were inhibited by 20?μL of EOT incorporated in tubes containing 4 mL of Sabouraud broth. In Sabouraud-chloramphenicol agar slants containing different concentrations of essential oil, 5?×?10? A. fumigatus spores were inhibited by 6?μL (0.0015?mL?mL?1) of the EOT. It has shown good anti-C. albicans and anti-A. fumigatus activity. All the dermatophytes tested were inhibited by 3?μL (0.00075?mL?mL?1) of EOT; the latter has the potential to be a good alternative to the conventional antifungal drugs which are usually expensive and with high toxicity. 相似文献
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Stereocontrol in Dinuclear Triple Lithium‐Bridged Titanium(IV) Complexes: Solving Some Stereochemical Mysteries
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Prof. Dr. Markus Albrecht Dr. Elisabeth Isaak Dr. Verena Moha Prof. Dr. Gerhard Raabe Dr. Roland Fröhlich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(22):6650-6658
Compounds 1 a – f ‐H2 form “monomeric” triscatecholate titanium(IV) complexes [Ti( 1 a – f )3]2?, which in the presence of Li cations are in equilibrium with the triple lithium‐bridged “dimers” [Li3(Ti( 1 a – f )3)2]?. The equilibrium strongly depends on the donor ability of the solvent. Usually, in solvents with high donor ability, the stereochemically labile monomer is preferred, whereas in nondonor solvents, the dimer is the major species. In the latter, the stereochemistry at the complex units is “locked”. The configuration at the titanium(IV) triscatecholates is influenced by addition of chiral ammonium countercations. In this case, the induced stereochemical information at the monomer is transferred to the dimer. Alternatively, the configuration at the metal complexes can be controlled by enantiomerically pure ester side chains. Due to the different orientation of the ester groups in the monomer or dimer, opposite configurations of the triscatecholates were observed by circular dichroism (CD) spectroscopy for [Ti( 1 c – e )3]2? or [Li3(Ti( 1 c – e )3)2]?. A surprising exception was found for the dimer [Li3(Ti( 1 f )3)2]?. Herein, the dimer is the dominating species in weak donor (methanol), as well as strong donor (DMSO), solvents. This is due to the bulkiness of the ester substituent destabilizing the monomer. Due to the size of the substituent in [Li3(Ti( 1 f )3)2]? the esters have to adopt an unusual conformation in the dimer resulting in a stereocontrol of the small methyl group. Following this, opposite stereocontrol mechanisms were observed for the central metal‐complex units of [Li3(Ti( 1 c – e )3)2]? or [Li3(Ti( 1 f )3)2]?. 相似文献
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Moha Outirite Mounim Lebrini Michel Lagrenée Fouad Bentiss 《Journal of heterocyclic chemistry》2007,44(6):1529-1531
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V. Mohaček-Grošev D. Kirin 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(1):85-90
Methyl-mercury(II) halides CH3HgX (X = Cl, Br and I) were studied by means of temperature dependent Raman spectroscopy from 10 K to 410 K. In addition to
the previously reported soft phonons, new changes in the low frequency spectra were observed at T
≈ 70 K in CH3HgBr and at T
≈ 100 K in CH3HgI. The bandwidths of the two internal modes in CH3HgBr, the CH3 symmetric stretching band and the C-Hg-Br bending band, rise towards a local maximum at T
≈ 50 K as the temperature is raised from 10 K to 300 K. On the other hand the bandwidths of the two corresponding modes in CH3HgI crystals monotonously increase with temperature, obeying an Arrhenius law. Besides the three phonon modes present in the
Raman spectra of CH3HgCl at room temperature, the fourth phonon band that has been observed at temperatures below 245 K might correspond to the
freezing of methyl librations. The huge bandwidth of the C-Hg-Br bending mode could suggest the presence of additional weak
bonding of a mercury atom with bromine atoms from other molecules, thus inducing positional disorder.
Received 19 November 1999 and Received in final form 10 November 2000 相似文献