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排序方式: 共有106条查询结果,搜索用时 15 毫秒
51.
52.
Anca Paun Irina Zarafu Miron T. Caproiu Constantin Draghici Maria Maganu Ani I. Cotar Mariana C. Chifiriuc Petre Ionita 《Comptes Rendus Chimie》2013,16(7):665-671
Starting from benzocaine, a well-known anaesthetic, ten derivatives were synthesized and characterized by UV–vis, IR, NMR, and elemental analysis. Most of the compounds contain residues with recognized biological activity, like nicotinic acid (vitamin B3 or PP), biotin (vitamin B7 or H), lipoic acid (thioctic acid), adamantine, as well as other residues of crown-ether type, benzofurazane, naphtylurea, di- and tri-nitrobenzene, and a nitroxide radical. The biological evaluation of the obtained compounds included hydrophobicity (lipophobicity) assay, total antioxidant and microbiological activity tests. 相似文献
53.
Viktor O. Iaroshenko Friedrich ErbenSatenik Mkrtchyan Ani Hakobyan Marcelo Vilches-HerreraSergii Dudkin Alina Bunescu Alexander VillingerVyacheslav Ya. Sosnovskikh Peter Langer 《Tetrahedron》2011,67(41):7946-7955
4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins react with electron-rich aminoheterocycles, dimethyl 1,3-acetonedicarboxylate, hydrazines, alkyl thioglycolates, and methyl sarcosinate to give a variety of 3,4-heteroannulated coumarins. The starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride. An NMR study and X-ray crystallographic analysis are reported. 相似文献
54.
55.
Neema Ani Mangalam M.R. Prathapachandra Kurup 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,71(5):2040-2044
Four oxovanadium and one dioxovanadium complex with 2-hydroxyacetophenone N(4)-phenylthiosemicarbazone (H2L) which are represented as [VOLphen]·2H2O (1), [VOLbipy] (2), [VOLdmbipy] (3), [VOL]2 (4) and [VO2HL]·CH3OH (5) have been synthesized and characterized by elemental analyses, electronic, infrared and EPR spectral techniques. In all the complexes 1–4 the ligand coordinates through phenolic oxygen, azomethine nitrogen and thiolate sulfur. But in complex [VO2HL]·CH3OH, coordination takes place in thione form instead of thiolate sulfur. All the complexes except [VO2HL]·CH3OH are EPR active due to the presence of an unpaired electron. In frozen DMF at 77 K, all the oxovanadium(IV) complexes show axial anisotropy with two sets of eight line patterns. 相似文献
56.
Neema Ani Mangalam Sarika Sivakumar M.R. Prathapachandra Kurup Eringathodi Suresh 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):686-692
The syntheses and characterization of six copper(II) complexes of 2-benzoylpyridine benzhydrazone in the form of [Cu(BPB)2], [Cu(BPB)Cl]·H2O, [Cu(BPB)Br], [Cu2(BPB)2](ClO4)2·4H2O, [Cu(BPB)N3]·H2O, and [Cu(BPB)NCS]·H2O·CH3OH are reported. The analytical methods used for the characterization of complexes include partial elemental analyses, IR, electronic and EPR spectra, conductivity measurements, magnetic susceptibility measurements and single crystal X-ray diffraction. From the crystal structure, it is clear that the hydrazone adopts the E conformation about the azo bond to attach to the metal through the Npy–Nazo–O chelating system. In the EPR spectra of complexes in DMF at 77 K four hyperfine quartets in the parallel region could be resolved and a half field signal is observed at 1500 G for complex [Cu2(BPB)2](ClO4)2·4H2O in polycrystalline state at 298 K which gives evidence for its binuclear nature indicating a weak interaction between the two Cu(II) ions. 相似文献
57.
The collisional removal of vibrationally excited OH(upsilon=1) by N(4S) atoms is investigated. The OH radical was prepared by 193 nm photolysis of H2O2, and N(4S) atoms were generated by a microwave discharge in N2 diluted in argon. The concentrations of OH(upsilon=0 and 1) were monitored by laser-induced fluorescence as a function of the time after the photolysis laser pulse. The N(4S) concentration was determined from the OH(upsilon=0) decay rate, using the known rate constant for the OH(upsilon=0) + N(4S) --> H + NO reaction. From comparison of the OH(upsilon=0 and 1) decay rates, the ratio of the rate constant k(upsilon=1)(OH-N) for removal of OH(upsilon=1) in collisions with N(4S) and the corresponding OH(upsilon=0) rate constant, k(upsilon=0)(OH-N) was determined to be 1.61 +/- 0.42, yielding k(upsilon=1)(OH-N) = (7.6 +/- 2.1) x 10(-11) cm3 molecule(-1) s(-1), where the quoted uncertainty (95% confidence limits) includes the uncertainty in k(upsilon=0)(OH-N). Thus, the collisional removal of OH(upsilon=1) by N(4S) atoms is found to be faster than for OH(upsilon=0). 相似文献
58.
Lun Wang Jie Fu Hongqi Chen Ani Liang Binbin Qian Bo Ling Cailing Zhou 《Journal of luminescence》2010,130(5):845-850
One-step aqueous synthesis of CdS nanoparticles as a novel fluorescence probe for sensitive and selective determination of DNA with synchronous fluorescence spectrometric method has been developed. Different from the traditional organometallic route, in which toxic precursors or solvents might be used, the wet chemical approach demonstrated in this paper is superior in terms of simplicity, using of nontoxic materials, mild synthetic condition and good reproducibility. When Δλ=255 nm, maximum synchronous fluorescence is produced at 264 nm, the synchronous fluorescence intensity of the composite nanoparticles is significantly decreased in the presence of trace DNA at PH 0.91. Under optimal conditions, the linear ranges of the calibration curves are 0.08-30.0 μg mL−1 for ctDNA and 0.05-35.0 μg mL−1 for hsDNA, respectively. The detection limits are 1.5 ng mL−1 for ctDNA and 2.2 ng mL−1 for hsDNA, respectively. Furthermore, the method is successfully applied to the quantification of DNA in synthetic samples. The results show that this proposed method is stable, sensitive and practical for the determination of trace DNA. 相似文献
59.
Santhi Ani Joseph Misha Hari Gaurav Sharma V.M. Hadiya V.P.N. Nampoori 《Optics Communications》2010,283(2):313-581
Dual beam mode-matched thermal lens method has been employed to measure the heat diffusion in nanofluid of silver with various volumes of rhodamine 6G, both dispersed in water. The important observation is an indication of temperature dependent diffusivity and that the overall heat diffusion is slower in the chemically prepared Ag sol compared to that of water. The experimental results can be explained assuming that Brownian motion is the main mechanism of heat transfer under the present experimental conditions. Light induced aggregation of the nanoparticles can also result in an anomalous diffusion behavior. 相似文献