排序方式: 共有35条查询结果,搜索用时 15 毫秒
21.
Dayananda BP Revanasiddappa HD Kiran Kumar TN 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(5):1333-1338
A simple and sensitized spectrophotometric method for the determination of trace amounts of beryllium has been described. The method is based on the formation of a ternary complex by the reaction of beryllium with haematoxylin in the presence of micellar medium (cationic surfactant, cetyltrimethylammonium bromide). The ternary complex of beryllium has a maximum absorbance at 592 nm and showed an excellent sensitivity (molar absorption coefficient of 7.07 x 10(4)L mol(-1)cm(-1) and the Sandell's sensitivity being 1.27 x 10(-4) microg cm(-2)) and reproducibility (within-day precision: R.S.D.相似文献
22.
A Facile Spectrophotometric Determination of Nitrite Using Diazotization with p-Nitroaniline and Coupling with Acetyl Acetone 总被引:4,自引:0,他引:4
A simple and sensitive spectrophotometric method is described for the determination of nitrite in water and soil samples.
The method is based on the reaction of nitrite with p-nitroaniline to form a diazonium ion, which is coupled with a new coupling
agent, acetyl acetone in an alkaline medium. The dye shows an absorption maximum at 490 nm and obeys Beer’s law over a range
of 0.5 to 14 μg nitrite per 10 mL analyte. The molar absorptivity of the colour system is 3.2×104 L mol−1 cm−1. The relative standard deviation is 2.7% (n = 10). The dye formed is stable for 3 h. The effect of interfering ions on the
determination is described. The method has been suggested for the determination of nitrite in water and soil samples. The
results obtained were compared with the standard N-(1-naphthyl) ethylenediamine dihydrochloride method.
Received April 12, 2001. 相似文献
23.
Sharma Disha Revanasiddappa Hosakere D. Jayalakshmi Basavegowda 《Journal of the Iranian Chemical Society》2020,17(1):43-58
Journal of the Iranian Chemical Society - Eight new coordination compounds of Mn(III) with (E)-2-((3-(benzyloxypyridinylimino) methyl)-4-bromophenol (L1), (E)-2-((3-(benzyloxypyridinylimino)... 相似文献
24.
Prasad KS Kumar LS Chandan S Jayalakshmi B Revanasiddappa HD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):276-282
Four Schiff base ligands and their corresponding organotin(IV) complexes have been synthesized and characterized by elemental analyses, IR, (1)H NMR, MS and thermal studies. The Schiff bases are obtained by the condensation of 3-amino-2-methyl-4(3H)-quinazolinone with different substituted aldehydes. The elemental analysis data suggest the stoichiometry to be 1:1 ratio formation. Infrared spectral data agreed with the coordination to the central metal ion through imine nitrogen, lactam oxygen and deprotonated phenolic oxygen atoms. All the synthesized compounds have been evaluated for antimicrobial activity against selected species of microorganisms. In addition, DNA binding/cleavage capacity of the compounds was analyzed by absorption spectroscopy, viscosity measurements and gel electrophoresis methods. 相似文献
25.
26.
27.
Reshma Sathyanarayana Boja Poojary Revanasiddappa B. Chandrashekarappa Hemanth Kumar Vijay K. Merugumolu 《中国化学会会志》2020,67(8):1501-1516
Fourteen novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives bearing benzimidazole moiety ( 7a-n ) have been synthesized using the one-pot nitro reductive cyclization method. All the synthesized compounds were confirmed by 1H nuclear magnetic resonance (1H NMR), 13C NMR, fourier-transform infrared (FT-IR), mass spectrum, and elemental analyses. All the title compounds were subjected to in vitro antioxidant activity. The free radical scavenging activity of the compounds was examined using DPPH, nitric oxide, and superoxide radical scavenging methods. The results demonstrated that compound 3-(2-(3,4-dimethoxyphenyl)-1-propyl-1H-benzo[d]imidazol-5-yl)-6-4-tolyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine ( 7c ) was potent in scavenging both DPPH and nitric oxide radical with IC50 values of 13.57 and 18.55 μg/ml when compared to the standard with IC50 values of 23.75 and 23.14 μg/ml, respectively, which was due to the presence of electron-donating groups. The activity was found to decline when electron-donating groups were replaced by electron-withdrawing groups. Moderate scavenging activity was observed for the superoxide radical. Structure activity relationship and physiochemical properties were studied for all the derivatives. 相似文献
28.
AbstractA series of seven coumarinyl-amino acid ester conjugates have been synthesized and characterized by NMR (1H and 13C) and mass spectra. Further, the compounds were investigated for their therapeutic applications such as anti-inflammatory and antioxidant activities. Among the synthesized compounds most of the analogs showed good efficiency compared with the standard. 相似文献
29.
Subramanya Gopal Hegde Vijayakumar G. Revanasiddappa Suchetan P. Adimule Suman Y. Reddy Atanu Ghoshal 《合成通讯》2013,43(19):2485-2495
A new julolidine hybrid analogs have been accomplished in a regio and stereo controlled manner using heterogenous MgSiO3 nanoparticles (NPs) catalyzed intramolecular dipolar cycloaddition reaction as a key step. The synthesized catalyst was used in the preparation of various new julolidine analogs with a good yield ranging from 65 to 85%. Further, catalyst could be recycled in several times without loss of significant activity which was an added advantage to the principles of green chemistry. 相似文献
30.
A sensitive and selective spectrophotometric method for the determination of trace amounts of chromium(VI) is described, based on diazotization and coupling reactions. Chromium(VI) oxidizes hydroxylamine in acetate buffer of pH 4.0 ± 0.5 to nitrite, which then diazotizes p-aminoacetophenone to form diazonium salt. The diazonium salt is then coupled with a new coupling agent, citrazinic acid in an alkaline medium, which gives an azo dye with an absorption maximum at 470 nm, a molar absorptivity of 2.12 × 104L mol–1cm–1, and a Sandell's sensitivity of 0.00246 g/cm2. The color is stable for 6 h and the system obeys Beer's law in the range 2–15 g chromium(VI) in a final volume of 10 mL. The detection limit of chromium(VI) is 0.04 g/mL. Chromium(III) can be determined after it is oxidized with bromine water in an alkaline medium to chromium(VI). The developed method has been successfully applied to the analysis of chromium in alloy steels, industrial effluents, and pharmaceutical preparations. 相似文献