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271.
Ferroelectric Lead Nitrogen Phosphate (LNP) single crystals have been synthesized using the controlled reaction between lead nitrate and orthophosphoric acid solutions by slow diffusion process in silicagel medium. The colourless transparent LNP crystals upto 6 × 4 × 3 mm3 in size have been grown at room temperature. The dielectric measurements have been carried out in the temperature range between 300 to 690 K. The effect of applied frequency on the dielectric constants and dielectric losses has been investigated. It has been observed that the mechanism of the dielectric behaviour is different in the lower and higher frequency and temperature ranges. The activation energy of the oscillators has been calculated and found to be 1.125 eV. Attempt has been made to draw some qualitative conclusions, taking in view, the existing theories of various kinds of polarizations and implications. 相似文献
272.
Mahesh H. Shinde Dr. Chepuri V. Ramana 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(71):17171-17175
The sequential functionalization of indole C2 and C3 in an umpolung fashion was executed with a predesigned substrate and choice of reagents. The developed method comprises gold-catalysed alkynol cycloisomerisation/intramolecular addition of C2 of indole and subsequent BF3 ⋅ OEt2-mediated regioselective C3 allylation, resulting in the synthesis of the functionalized indoloisoquinolinone scaffold. The reaction involves 5-endo-alkynol cycloisomerisation and the dearomative addition of indole C2 to the intermediate oxocarbenium cation, which results in two equilibrating fused and spiropentacyclic intermediates, which upon treatment with allyl silane in the presence of BF3 ⋅ OEt2, undergo selective indole C3 allylation. Other nucleophiles, such as hydride, azide and indole, were also found to be compatible with this process. 相似文献
273.
The keto and gem-ester functionalities of cyclohexanonedicarboxylates (1) offer a facile route for the synthesis of 5,7-diarylspiro[4,5,6,7-tetrahydrobenzo[d][1,2,3]selena/thiadiazole-6,5′-(hexahydropyrimidine)]-2′,4′,6′-triones (6 and 8) and -2′-thioxo-4′,6′-diones (7 and 9). The new compounds were characterized by IR, NMR, and CMR spectral data. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 17–23, 1999 相似文献
274.
A water soluble compound, (2-((1H-benzimidazol-2-yl)methylamino)acetic acid, BIGH, has been synthesized and structurally characterized by elemental analysis, IR and UV spectroscopies, 1H-NMR, thermogravimetric and differential thermal analyses, and single crystal and powder X-ray diffraction. BIGH can act as a flexible planar ligand with three potential coordination sites. It crystallizes in a monoclinic system with the sp. gr. P21/c with the unit cell parameters, a = 9.3764(7) Å, b = 11.5031(8) Å, c = 10.0543(6) Å, and Z = 4. The crystal structure was stabilized through inter-molecular hydrogen bonds. The anti-microbial activity of the compound has been studied against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus, which showed a good activity against Bacillus subtilis. Cyclic voltammogram of the compound shows that it is a redox-active molecule. 相似文献
275.
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277.
Pritty Rao G. L. N. Reddy S. Vikram Kumar J. V. Ramana N. Chattopadhyay A. K. Basu Seema Srivastava R. K. Sarin V. S. Raju Sanjiv Kumar 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):127-130
The paper describes the simultaneous determination of 14N and 15N isotopes in opium by proton induced γ-ray emission (PIGE) technique. The isotopic ratio of 14N and 15N is a useful parameter for assigning provenance of (seized) illicit drugs. The measurement, non-destructive in nature, is performed on pellets made up of opium powders and is based on the prompt detection of 2.313 and 4.4 MeV γ-rays emanating from 14N(p,p′γ)14N and 15N(p,αγ)12C nuclear reactions respectively, induced simultaneously by 3.6–3.8 MeV proton beam. Positive as well as negative deviations from the natural isotopic abundance (99.63:0.37) were observed in the samples. The precision of the measurements is about 4%. The methodology provides an easy and rapid approach to determine the isotopic ratio of 14N and 15N and has been used for the first time in the analysis of opium. 相似文献
278.
Venkataramana R. Ramana Reddy Ch. Venkata Ashok D. Nagaraju N. 《Russian Journal of General Chemistry》2017,87(4):850-856
Russian Journal of General Chemistry - A new series of linear and angular alkyl substituted furochromanone derivatives have been synthesized in one pot microwave irradiation assisted process from... 相似文献
279.
Yellapurkar Ishita Bhabal Sonal Ramana M. M. V. Jangam Kundan Salve Vaibhav Patange Sunil More Paresh 《Research on Chemical Intermediates》2021,47(7):2669-2687
Research on Chemical Intermediates - Magnetically separable magnesium ferrichromate nanoparticles (MgFeCrO4 NPs) were synthesized by aqueous combustion synthesis (ACS) using glycine as the fuel.... 相似文献
280.
Research on Chemical Intermediates - A series of 1-[aryl-(thiazol-2-ylamino)-methyl]-naphthalen-2-ol derivatives were synthesized using porcine pancreatic lipase as a catalyst. The major assets of... 相似文献