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51.
52.
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
53.
Jitender Gaur Shilpa Jain Rohit Bhatia Arun Lal Narender Kumar Kaushik 《Journal of Thermal Analysis and Calorimetry》2013,112(2):1137-1143
We demonstrate synthesis of water insoluble, novel copolymer PA1 from condensation of glyoxal dihydrazone and glyoxal dihydrazone bis(dithiocarbamate) monomers having high capacity to remove metal ions from aqueous solution. The presence of a high atomic percentage of nitrogen and sulfur atoms in PA1 leads to strong ligating ability with metal ions. The monomers and the polymer have been characterized by FTIR, UV–Visible spectroscopy, CHNS elemental analysis, NMR, MALDI-MS, and TG/DTA. As a proof of concept, the PA1 is tested for its ability to remove heavy metal ions Cu2+, Co2+, Fe2+, Ni2+, Mn2+, and CrO 7 2? from aqueous solutions. PA1 efficiently removed metals ions from the metal solutions. The highest absorption ability has been observed toward the iron salts where 0.969 g metal salt is absorbed by 1 g polymer. This study has implication for inexpensive and efficient polymer for purification of water. 相似文献
54.
First‐principles DFT calculations are carried out to study the changes in structures and electronic properties of two‐dimensional single‐layer graphene in the presence of non‐covalent interactions induced by carbon and boron fullerenes (C60, C70, C80 and B80). Our study shows that larger carbon fullerene interacts more strongly than the smaller fullerene, and boron fullerene interacts more strongly than that of its carbon analogue with the same nuclearity. We find that van der Waals interactions play a major role in governing non‐covalent interactions between the adsorbed fullerenes and graphene. Moreover, a greater extent of van der Waals interactions found for the larger fullerenes, C80 and B80, relative to smaller C60, and consequently, results in higher stabilisation. We find a small amount of electron transfer from graphene to fullerene, which gives rise to a hole‐doped material. We also find changes in the graphene electronic band structures in the presence of these surface‐decorated fullerenes. The Dirac cone picture, such as that found in pristine graphene, is significantly modified due to the re‐hybridisation of graphene carbon orbitals with fullerenes orbitals near the Fermi energy. However, all of the composites exhibit perfect conducting behaviour. The simulated absorption spectra for all of the graphene–fullerene hybrids do not exhibit a significant change in the absorption peak positions with respect to the pristine graphene absorption spectrum. Additionally, we find that the hole‐transfer integral between graphene and C60 is larger than the electron‐transfer integrals and the extent of these transfer integrals can be significantly tuned by graphene edge functionalisation with carboxylic acid groups. Our understanding of the non‐covalent functionalisation of graphene with various fullerenes would promote experimentalists to explore these systems, for their possible applications in electronic and opto‐electronic devices. 相似文献
55.
Chitrakara Hegde Arun M. Isloor Mahesh Padaki Hoong-Kun Fun 《Arabian Journal of Chemistry》2013,6(3):319-326
The present work describes about the synthesis and characterization of Polysulfone blend nanoporous membrane with nonwoven support. This Nonwoven support provides mechanical strength to membrane while filtration process and minimizes membrane fouling. Hence it helps in better membrane performance in terms of salt rejection, improved flux, thermal stability and fairly increases in proton conductivity. In this work we have used K.C.270 nonwoven material consisting of fine polyester fibers and has a thickness of below 110 μm. 相似文献
56.
Shridhar Malladi Arun M. Isloor Shrikrishna Isloor D.S. Akhila Hoong-Kun Fun 《Arabian Journal of Chemistry》2013,6(3):335-340
In the present study a series of new Schiff bases were synthesized. All the synthesized compounds were characterized by IR, 1H NMR, mass spectral and elemental analyses. Newly synthesized compounds were screened for their antibacterial (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa) activity. The results revealed that, compounds 3f and 3c have exhibited significant biological activity against the tested microorganisms. 相似文献
57.
Short and convenient synthesis of bicyclic lactones (1) and (2), important intermediates in trichothecene synthesis is described. 相似文献
58.
A recent report by El Feraly et. al 3 describing the direct conversion of 5, 7-dimethoxy - 2, 3 - dihydro - 1H-benzcyclopenten- 1 -one(1) to the homologated aldehyde (3) by dimethyl sulfonium 4 methylide4 (2), prompted us to present results obtained from our investigation of the reaction of various aromatic aldehydes and ketones, possessing electron releasing p-substituent, with (2). Our interest in examining this particular reaction arose from a need to prepare the oxirane (5) and the aldehyde (6), required in connection with the synthesis and biological evaluation of semi-rigid analogues of catecholamines as probes for the study 5 of adrenergic and dopaminergic receptors.5 相似文献
59.
Atul C. Chaskar Arun A. Yadav Bhushan P. Langi Anita Murugappan Chetan Shah 《合成通讯》2013,43(19):2850-2856
Simple, efficient, and mild method for α-thiocyanation of ketones in presence of heteropolyacid has been developed. This methodology offered α-oxothiocyanates in good to excellent yields at room temperature in a highly selective manner. The catalyst could be efficiently recovered from the reaction and reused. 相似文献
60.
A mild, efficient, and highly regio- and stereoselective method for the methoxy and ethoxy bromination of olefins has been developed using NH4Br as a bromine source and Oxone as an oxidant. Various kinds of olefins (aromatic, linear, and cyclic olefins) afforded the corresponding alkoxy brominated products in moderate to excellent yields. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.] 相似文献