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排序方式: 共有127条查询结果,搜索用时 62 毫秒
51.
Hanumanthrayappa Manjunatha Doddahalli Hanumantharayudu Nagaraju Gurukar Shivappa Suresh Thimmappa Venkatarangaiah Venkatesha 《Electroanalysis》2009,21(20):2198-2206
The properties of graphite electrode (Gr) modified with poly(diallyl dimethyl ammonium chloride) (PDDA) for the detection of uric acid (UA) in the presence of dopamine (DA) and high concentration of ascorbic acid (AA) have been investigated by cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The polymer modified graphite electrode was prepared by a very simple method just by immersing the graphite electrode in PDDA solution for 20 minutes. The PDDA/Gr modified electrode displayed excellent electrocatalytic activity towards the oxidation of UA, DA and AA compared to that at the bare graphite electrode. The electrochemical oxidation signals of UA, DA and AA are well resolved into three distinct peaks with peak potential separations of 220 mV, 168 mV and 387 mV between AA‐DA, DA‐UA and AA‐UA respectively in cyclic voltammetry studies and the corresponding peak potential separations are 230 mV, 130 mV and 354 mV respectively in differential pulse voltammetry. The lowest detection limits obtained for UA, DA and AA were 1×10?7 M, 2×10?7 M and 800×10?9 M respectively. The PDDA/Gr electrode efficiently eliminated the interference of DA and a high concentration of AA in the determination of UA with good selectivity, sensitivity and reproducibility. The modified electrode was also successfully applied for simultaneous determination of UA, DA and AA in their ternary mixture. 相似文献
52.
Gomathi Devi Lakshmipathi Naik Nagaraju Kottam Girish Kumar Shivashankar 《中国化学》2010,28(11):2151-2161
Mn2+ ion was doped into the TiO2 matrix and its photocatalytic activity was evaluated for the degradation of a mono azo dye methyl orange (MO) and a di‐azo dye brilliant yellow (BY) under UV/solar light. X‐ray diffraction results revealed the phase transformation from anatase to rutile due to the inclusion of Mn2+ ion into the TiO2 matrix. All the doped catalysts showed a red shift in the band gap to the visible region. The degradation reaction of the dyes was found to be dependent on its structure. It was found that mono azo dye degrades faster than di azo dye under UV/solar light. The rate constant under identical conditions calculated for the degradation of MO is 2.4 times (under UV light) and 4.5 times (under solar light) higher compared to BY. Among the photocatalysts studied, Mn2+(0.06 at.%)‐TiO2 showed higher activity under both UV and solar light illumination. The synergestic effect in the bicrystalline framework of anatase and rutile effectively suppresses the charge carrier recombination and enhances the photocatalytic activity. The degradation reaction was followed by UV‐visible spectroscopy and the photoproducts formed were analyzed by GC‐MS techniques. 相似文献
53.
Ganganagappa Nagaraju Pallellappa Chithaiahb Siddaramanna Ashokac Narayanappa Mahadevaiah 《Crystal Research and Technology》2012,47(8):868-875
In this paper, we report a synthesis, characterization and electrochemical properties of V2O5 nanobelts. V2O5 nanobelts have been prepared via hydrothermal treatment of commercial V2O5 in acidic (HCl/H2SO4) medium at relatively low temperature (160 °C). The hydrothermally derived products have been characterized by powder X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), Raman spectroscopy, X‐ray photo electron spectroscopy (XPS), UV‐Vis spectroscopy, Scanning/Transmission electron microscopy (SEM/TEM). XRD pattern of V2O5 nanobelts show an orthorhombic phase. From the FTIR spectrum, the peak observed at 1018 cm−1 is characteristic of the stretching vibration mode of the terminal vanadyl, V = O. The UV‐Vis absorption spectrum of V2O5 nanobelts show maximum absorbance at 430 nm, which was blue‐shifted compared to that of bulk V2O5. TEM micrographs reveal that the products consist of nanobelts of 40‐200 nm in thickness and several tens of micrometers in length. The electrochemical analysis shows an initial discharge capacity of 360 mAh g−1 and its almost stabilized capacity is reached to 250 mAh g−1 after 55 cycles. A probable reaction mechanism for the formation of orthorhombic V2O5 nanobelts is proposed. 相似文献
54.
Chaithra Nagaraju Swarup Hassan Ashok Sadashivamurthy Shamanth Sandhya C. Nagarakere Makanahalli P. Sunilkumar 《合成通讯》2020,50(17):2647-2654
Abstract A facile and conveniently simple new protocol is devised for the synthesis of 3,5-disubstituted and annulated isothiozoles under transition metal and catalyst free conditions utilizing easily available acetophenones, dithioesters and NH4OAc. This strategy involves C=O and C=S functionalization via sequential imine formation followed by intra molecular cyclization and aerial oxidation forming consecutive C?N and S?N bonds respectively in one pot. This protocol offers a low cost, user friendly, straight forward and widely applicable approach to 3,5-disubstituted isothiazoles. 相似文献
55.
Manjunath Giridhar Halehatty S. Bhojya Naik Chatnalli N. Sudhamani Mustur C. Prabakara Rajappa Kenchappa Nagaraju Venugopal Sameer Patil 《中国化学会会志》2020,67(2):316-323
ZnO nanoparticles were successfully synthesized using a microwave method, whose surface was modified with {4-[(E)-2-(furan-2-yl)ethenyl]pyridin-1-ium-1-yl}acetate as a capping agent (1 and 3%). Their structural properties were investigated using FTIR, XRD, SEM, EDS, and UV–visible spectroscopy. XRD confirmed the Wurtzite structure for all compounds, a size of 30.6 nm for uncapped and 22.9 nm for 3% dye-capped nanoparticles were calculated from Scherer's equation. Hexagonal wurtzite shape of nanoparticles can be clearly seen in the SEM images. The DFT calculations were carried out using quantum espresso. These dye-capped ZnO nanoparticles were proved to be potential antibacterial agents, the minimum concentrations of dye-capped ZnO nanoparticles that inhibit the growth of bacteria are 1.5 mg/mL for Escherichia coli and 0.78 mg/mL for Bacillus subtilis, which are much lower than those of uncapped ZnO. The bioactivity data suggest these organic–inorganic hybrid nanoparticles emerged as a new class of antibacterial agents. 相似文献
56.
One‐Pot Three‐Component Domino Reaction for the Synthesis of Novel Spiro Indolinyl Isoxazolo[2,3‐c][1,3,5]Thiadiazepinones Catalyzed by PTSA
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Rajanarendar Eligeti Nagaraju Dharavath Ramakrishna Saini 《Journal of heterocyclic chemistry》2014,51(6):1814-1817
The synthesis of novel spiro indolinyl isoxazolo[2,3‐c] [1,3,5]thiadiazepinones has been achieved by using one‐pot three‐component domino reaction from 3‐amino‐5‐methylisoxazole, substituted isatins, and mercapto acetic acid by employing p‐toluene sulfonic acid as Lewis acid catalyst. The salient features of the present method are mild reaction conditions, cost effective, environmentally benign, high yields of products and operational simplicity. 相似文献
57.
Girijesh Kumar Verma Gaurav ShuklaAnugula Nagaraju Abhijeet SrivastavaMaya Shankar Singh 《Tetrahedron》2014
An operationally simple and efficient one-pot straightforward method for the construction of 1,3-thiazolidin-4-ones has been developed by cyclocondensation of β-ketothioamides and an in situ generated acid anhydride from α-halocarboxylic acid in the presence of DCC at room temperature. The attractive features of this strategy include metal-free mild reaction conditions, short reaction time, and efficacy of forming consecutive C–S and C–N bonds and one ring in a single synthetic operation. Noteworthy, a Z-stereochemistry was observed for the exocyclic α-oxoketene moiety at 2-position of 1,3-thiazolidine ring. 相似文献
58.
59.
Radha Krishna Singamsetty Satish Kumar Vujjini Nagaraju Manne Brahmeshwara Rao Mandava Venkata Naga Vurimidi Himabindu Apurba Battacharya 《合成通讯》2013,43(24):4452-4459
A noninfringing synthesis of simvastatin 1, starting from lovastatin 2, is presented. This synthesis features the protection of the free hydroxyl group of the lovastatin with 3,4-dihydro-2H-pyran (DHP) and opening of the lactone ring with n-BuNH2 to afford amide 4 as a key intermediate. 相似文献
60.
2,6-Dichloropurine hydrochloride reacts with various types of alcohols using different alumina catalysts and converts into its N-9-alkyl-2-chloro-6-hydroxy-9H-purine products to an extent of 49–74%. The product selectivity depends on the stability of carbocation generated from the alcohol. More stable carbocation formulates both N-7 and N-9-alkyl-2,6-dichloropurine products, whereas the less stable carbocation results in exclusively N-9-alkyl-2-chloro-6-hydroxy-9H-purine. The catalytic activity of alumina prepared using the sol-gel method has larger Brunauer, Emmett, and Teller (BET) surface area and hence shows significantly greater catalytic activity than the commercially available alumina samples. 相似文献