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11.
Summary The formation constants of mixed-ligand complexes of cobalt(II) and nickel(II) with glycine, DL--alanine and DL-valine as primary ligands and imidazole as secondary ligand have been determined potentiometrically under physiological-like conditions (T=37°C and I=0.15 M KNO3). The proton association constants of the free ligands and the stability constants for binary systems involving the amino acids and imidazole were also determined under identical conditions, and the experimental pH-titration data were analysed using the computer SUPERQUAD program. The relative stability of the ternary complex as compared to that of the corresponding binary complexes has been quantitatively expressed in terms of log K and log X values. 相似文献
12.
Summary Mixed-ligand complexes of CuII and ZnII with glycine(GL), DL--alanine (AL) and DL-valine (VL) as primary ligands and imidazole (IM) as secondary ligand have been studied potentiometrically under physiological conditions (t=37° C and I=0.15 M KNO3). The experimental pH-titration data were analysed with aid of the SUPERQUAD computer program in order to evaluate formation constants of binary and ternary systems involying amino acids (AA) and IM. The relative stability of each of the ternary complexes was compared with that of corresponding binary complexes in terms of log K and log X values. 相似文献
13.
Meghna Ghosh Sanjukta Parida Huma Khatoon Nanigopal Bera Sabyashachi Mishra Nilmoni Sarkar 《Chemphyschem》2023,24(16):e202300174
Curcumin, a well-known medicinal pigment, has seen limited applications in biology despite having great potential as a therapeutic drug. Deprotonation is one of the possible ways to enhance solubility of curcumin in polar solvent. Here, we have explored the effect of deprotonation on the ultrafast dynamics of this biomolecule with the help of the time-resolved fluorescence spectroscopic measurements using the femtosecond fluorescence upconversion technique. The excited state photophysics of fully deprotonated curcumin significantly differs from that of neutral curcumin. We have observed that the completely deprotonated curcumin not only has higher quantum yield, but also higher excited state lifetime and slower solvation dynamics in comparison to neutral curcumin. We propose solvation dynamics and intramolecular charge transfer as the excited state processes associated with the radiative decay of the completely deprotonated molecule, while ruling out the possibility of excited state proton exchange or proton transfer. Our results are well supported by time-dependent density-functional theory calculations. Lastly, we have also demonstrated the possibility of modulating the ultrafast dynamics of fully deprotonated curcumin using non-aqueous alkaline binary solvent mixtures. We believe our results will provide significant physical insight towards unveiling the excited state dynamics of this molecule. 相似文献
14.
TLC Determination of Strychnine and Brucine of Strychnos nux vomica in Ayurveda and Homeopathy Drugs
Strychnos nux vomica is an important plant source for drugs of ayurvedic and homeopathic system of medicine. In this paper a thin layer chromatographic
(TLC) method has been developed for the quantitative estimation of the two major alkaloids strychnine and brucine in the plant
fruit and in ayurvedic and homeopathic drugs. Chloroform–ethyl acetate–diethyl amine (0.5:8.5:1) as mobile phase gave clear
separation with no interference between the bioactive markers. The R
f
values for strychnine and brucine were 0.55 and 0.42. The TLC method was found to be precise, rugged, robust and accurate
with recovery of strychnine in the range 93.11–99.82% and brucine 96.95–99.48%. The limit of detection (LOD) and limit of
quantification (LOQ) for strychnine were 1.9 and 8.25 ng and for brucine 2.2 and 9.2 ng respectively. 相似文献
15.
A new eudesmane sesquiterpene, pluchargen A (3-beta-[3'-chloro-2'-hydroxy-2'-methyl butyroyl]-cuauhtemone), was isolated from the whole plant of Pluchea arguta, and the structure was elucidated on the basis of 1- and 2-D NMR spectroscopic studies. 相似文献
16.
JPC – Journal of Planar Chromatography – Modern TLC - Dendrophthoe falcata (Linn. f.) Etting. is a stem parasite commonly known as ‘Vanda’ in the Ayurvedic system of... 相似文献
17.
A new melilotic ester, meliloester [2-ethyl-hexyl-3-(2-hydroxyphenyl) propionate], was isolated from the whole plant of Melilotus alba. Its structure was elucidated on the basis of spectroscopic and mass spectrometric analyses, including EI-MS, HR-MS, and UV, IR, 1D and 2D-NMR spectroscopic studies. 相似文献
18.
A new method for determining the O/U ratio in uranium oxide is described. The method consists of dissolving an accurately weighed sample in a known excess of ceric ammonium nitrate in 2N perchloric acid at room temperature and estimating the unreacted Ce/IV/ with benzohydroxamic acid. A standard deviation of 0.0016 for ten estimations is observed. 相似文献
19.
Hongwen Chen Bei-Er Jia Xinsheng Lu Dr. Yichuan Guo Rui Hu Dr. Rabia Khatoon Prof. Dr. Lei Jiao Prof. Dr. Jianxing Leng Prof. Dr. Liqiang Zhang Prof. Dr. Jianguo Lu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9973-9983
Tin diselenide (SnSe2), as an anode material, has outstanding potential for use in advanced lithium-ion batteries. However, like other tin-based anodes, SnSe2 suffers from poor cycle life and low rate capability due to large volume expansion during the repeated Li+ insertion/de-insertion process. This work reports an effective and easy strategy to combine SnSe2 and carbon nanotubes (CNTs) to form a SnSe2/CNTs hybrid nanostructure. The synthesized SnSe2 has a regular hexagonal shape with a typical 2D nanostructure and the carbon nanotubes combine well with the SnSe2 nanosheets. The hybrid nanostructure can significantly reduce the serious damage to electrodes that occurs during electrochemical cycling processes. Remarkably, the SnSe2/CNTs electrode exhibits a high reversible specific capacity of 457.6 mA h g−1 at 0.1 C and 210.3 mA h g−1 after 100 cycles. At a cycling rate of 0.5 C, the SnSe2/CNTs electrode can still achieve a high value of 176.5 mA h g−1, whereas a value of 45.8 mA h g−1 is achieved for the pure SnSe2 electrode. The enhanced electrochemical performance of the SnSe2/CNTs electrode demonstrates its great potential for use in lithium-ion batteries. Thus, this work reports a facile approach to the synthesis of SnSe2/CNTs as a promising anode material for lithium-ion batteries. 相似文献
20.
A. Khatoon Abadi H. R. Rezazadeh M. Mehrpooya A. Morovvatpoor F. Golgoii 《International Journal of Theoretical Physics》2011,50(10):3251-3274
This paper presents some mathematical aspects of Classical Liouville theorem and we have noted some mathematical theorems
about its initial value problem. Furthermore, we have implied on the formal frame work of Stochastic Liouville equation (SLE). 相似文献