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71.
Malik Abdul Waseem ShireenAnjali Srivastava Arjita SrivastavaRahila I.R. Siddiqui 《Tetrahedron letters》2014
Reusable [bmIm]OH was found to be a highly efficient renewable homogenous catalyst for the rapid and convenient synthesis of benzoxazine-4-one derivatives from o-iodobenzoic-acid and benzonitrile at 75 °C in moderate to good yields. This methodology provides a facile and straightforward path to construct other related heterocycles in an eco-compatible fashion. 相似文献
72.
Xiao-Jun Yang H.M. Srivastava Ji-Huan He Dumitru Baleanu 《Physics letters. A》2013,377(28-30):1696-1700
In this Letter, we propose to use the Cantor-type cylindrical-coordinate method in order to investigate a family of local fractional differential operators on Cantor sets. Some testing examples are given to illustrate the capability of the proposed method for the heat-conduction equation on a Cantor set and the damped wave equation in fractal strings. It is seen to be a powerful tool to convert differential equations on Cantor sets from Cantorian-coordinate systems to Cantor-type cylindrical-coordinate systems. 相似文献
73.
H. M. Srivastava Shy-Der Lin Shuoh-Jung Liu Han-Chun Lu 《Russian Journal of Mathematical Physics》2012,19(1):121-130
Motivated essentially by their potential for applications in the mathematical, physical, and statistical sciences, the object
of this paper is to investigate several general families of hypergeometric polynomials and their associated multiple integral
representations. By suitably specializing the main results presented here, the corresponding integral representations are
derived for familiar simpler classes of hypergeometric polynomials such as (for example) the Lagrange polynomials, Shively’s
pseudo-Laguerre polynomials, and generalized Bessel polynomials. Each of the integral representations derived in this paper
may be also viewed as a linearization relationship for the product of two different members of the associated family of hypergeometric
polynomials. 相似文献
74.
Hiroya Takada Yoshiaki Nishibayashi Sanjay Kumar Srivastava Kouichi Ohe Sakae Uemura 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):629-632
Asymmetric intramolecular selenocyclisation of alkenoic acids, alkenols and alkenyl urethanes using chiral ferrocenylselenenyl cations proceeds smoothly to give the corresponding lactones, cyclic ethers and N-heterocyclic compounds, respectively, in moderate yields with very high diastereoselectivities. 相似文献
75.
R. K. Gupta A. K. Sinha B. N. Raja Sekhar A. K. Srivastava G. Singh S. K. Deb 《Applied Physics A: Materials Science & Processing》2011,103(1):13-19
Controllable and uniform doping of nanowires (NWs) is the ultimate challenge prior to their effective application. Si NWs
amorphize and bend toward the impinging ions under ion irradiation as a result of viscous flow. We demonstrate that thermal
annealing induces a full recovery of the crystalline phase corresponding to the unbending of the NWs. The competition between
Solid Phase Epitaxy and Random Nucleation and Growth at the nanoscale is the key parameter controlling the recovery. 相似文献
76.
S. K. Srivastava Shailja Tomar Rupali Rastogi Richa Saxena 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):634-640
Six new substituted diphenyltin(IV) O,O′-alkylene dithiophosphates, (C6H5)2Sn(X)S(S) POGO [G = —CH2C(CH3)2CH2—, X = Cl (1), SCN (3), ClO4 (5); G = —CH2C (C4H9)(C2H5)CH2—, X = Cl (2), SCN (4), ClO4 (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, 1H, 13C, 31P, and 119Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established. 相似文献
77.
Ashok K. S. Chauhan Arun Kumar R. C. Srivastava 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):1057-1062
Abstract Activated tellurium, but not selenium, reacts with para-substituted benzoylmethyl bromides as well as with iodoacetamide at their melting points in absence of a solvent to give bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC6H4COCH2)2TeBr2, (Y = H, Me, and MeO) and bis(acetamido)tellurium diiodide, (H2NCOCH2)2TeI2, respectively. Quick reduction of (p-YC6H4COCH2)2TeBr2, with sodium metabisulphite in a two-phase system yields crystalline (p-YC6H4COCH2)2Te. These tellurides undergo smooth oxidative addition of halogens, interhalogen ICl or a pseudohalogen (SCN)2. Intramolecular coordination of the carbonyl group in these functionalized diorganotellurium dihalides is evident from IR spectra and shorter Te···O (carbonyl) distances in comparison to the sum of van der Waals radii and completes six coordination around Te atom. Not unexpectedly, therefore, intermolecular secondary bonding effects of the type Te…O, Te···X and X···X are missing in (PhCOCH2)2TeBr2, (p-MeOC6H4COCH2)TeBr2 and (PhCOCH2)2TeI2. Instead, these compounds provide rare examples, among organotellurium compounds, of supramolecular architecture, where C–H···Br and C–H···O hydrogen bonds and π-π (phenyl ring) interactions appear to be the noncovalent intermolecular associative forces that dominate the crystal packing. 相似文献
78.
Kiran Singhal Dharmendra K. Srivastava 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1673-1678
Abstract Interactions of HgX2 (X = Cl, Br, I, SCN, CN, NCO), SbCl3, TeCl4, and PhTeCl3 with Ph3Sn-O-SiPh3 at room temperature have been found to proceed with the simultaneous cleavage of Sn-O and Si-O bonds, invariably yielding Ph2SnO, Ph3SiX, and the corresponding organo-mercury, -antimony, and -tellurium derivatives. The course of the reactions suggests the instability of the Sn-O-M (M = Hg, Sb, Te) system. GRAPHICAL ABSTRACT 相似文献
79.
B. Biyani A. J. Campagna D. Daruwalla C. M. Srivastava P. Ehrlich 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):327-339
The molecular weight distribution (MWD) of crystallizable polyphenylacetylene prepared near room temperature in the presence of ferric acetylacetonate and triethylaluminum was determined through use of fractions characterized by vapor pressure osmometry and gel permeation chromatography (GPC). The number- and weight-average molecular weights (M n and M w) are both less than the molecular weight corresponding to the maximum of the weight distribution function, which lacks a high molecular weight tail. M wandM n is less than is consistent with models allowing for chain termination characteristic of vinyl polymers. GPC elution volumes are much less than those characteristic of polystyrene of similar molecular weight, and the Mark-Houwink exponent is high (2.4 for M v 4800 to 6800). These data indicate more rodlike behavior than for polystyrene of equivalent molecular weight. The MWD and other data suggest intramolecular chain termination, possibly associated with the molecule's tendency to form paramagnetic defect states. 相似文献
80.
Barium Manganate Oxidation in Organic Synthesis: Part—IV: Oxidation of Aldehydes to Carboxylic Acids
The oxidation of aldehydes to corresponding carboxylic acids by barium manganate under heterogeneous conditions is described. Aromatic aldehydes were smoothly converted to carboxylic acids while aliphatic aldehydes underwent polymerisation. 相似文献