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181.
R. S. Rathore K. Sathiyanarayanan N. S. Karthikeyan P. G. Aravindan 《Structural chemistry》2010,21(5):909-914
Derivatives of azabicyclo[3.3.1]nonanone tend to prefer for weak interactions in the crystal over strong N–H···O hydrogen
bonds. The main stabilizing forces in the investigated azatricyclo[7.3.1.02,7]trideca-trienone derivatives are C–H···O, N–H···π and C–H···π interactions, leading to interesting structural patterns. The
azabicyclo[3.3.1]nonanone ring adopts chair-envelope conformation having exo-C2,C4-aromatic substituents. Amino NH is in trigonal
pyramidal configuration. The interesting stereochemistry of azabicyclo[3.3.1]nonanone, driving exceptional preference for
weaker interactions over strong hydrogen bonds serves a useful example toward engineering and design strategy, and structure
prediction methodologies. 相似文献
182.
183.
Baril NF He R Day TD Sparks JR Keshavarzi B Krishnamurthi M Borhan A Gopalan V Peacock AC Healy N Sazio PJ Badding JV 《Journal of the American Chemical Society》2012,134(1):19-22
Hydrogenated amorphous silicon (a-Si:H) is one of the most technologically important semiconductors. The challenge in producing it from SiH(4) precursor is to overcome a significant kinetic barrier to decomposition at a low enough temperature to allow for hydrogen incorporation into a deposited film. The use of high precursor concentrations is one possible means to increase reaction rates at low enough temperatures, but in conventional reactors such an approach produces large numbers of homogeneously nucleated particles in the gas phase, rather than the desired heterogeneous deposition on a surface. We report that deposition in confined micro-/nanoreactors overcomes this difficulty, allowing for the use of silane concentrations many orders of magnitude higher than conventionally employed while still realizing well-developed films. a-Si:H micro-/nanowires can be deposited in this way in extreme aspect ratio, small-diameter optical fiber capillary templates. The semiconductor materials deposited have ~0.5 atom% hydrogen with passivated dangling bonds and good electronic properties. They should be suitable for a wide range of photonic and electronic applications such as nonlinear optical fibers and solar cells. 相似文献
184.
Ashish Kumar Singha Deb P. Ilaiyaraja D. Ponraju B. Venkatraman 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):877-883
Diglycolamide functionalized multi-walled carbon nanotubes (DGA-MWCNTs) were synthesized by sequential chemical reactions
for removal of uranium from aqueous solution. Characterization studies were carried out using FT-IR spectroscopy, XRD and
SEM analysis. Adsorption of uranium from aqueous solution on this material was studied as a function of nitric acid concentration,
adsorbent dose and initial uranium concentration. The uranium adsorption data on DGA-MWCNTs followed the Langmuir and Freundlich
adsorption isotherms. The adsorption capacity of DGA-MWCNTs as well as adsorption isotherms and the effect of temperature
on uranium ion adsorption were investigated. The standard enthalpy, entropy, and free energy of adsorption of the uranium
with DGA-MWCNTs were calculated to be 6.09 kJ mole−1, 0.106 kJ mole−1 K−1 and −25.51 kJ mole−1 respectively at 298K. The results suggest that DGA-MWCNTs can be used as efficient adsorbent for uranium ion removal. 相似文献
185.
Polypyrrole doped by Zn2+ ions was synthesized as nanocomposites with MWCNT by in-situ oxidative polymerization and investigated as electrode material for supercapacitors. The uniform coating of polypyrrole on MWCNT was characterized by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The effect of Zn2+ ions were characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical performances were investigated by cyclic voltammetry (CV), constant current charging/discharging cyclic test (CC) and electrochemical impedance spectroscopy (EIS) using a three-electrode system. The doped polypyrrole composites show higher specific capacitance and better cyclic stability. 相似文献
186.
Chiral and achiral pincer type palladium complexes bearing abnormal N-heterocyclic carbene ligands derived from 1,2,3-triazole are reported. Both complexes are effective as catalysts for non-asymmetric Suzuki coupling reaction for the synthesis of biphenyl derivatives. However, both the complexes failed to catalyze the formation of binaphthyl derivatives, by the asymmetric Suzuki coupling in case of the chiral complex and the non-asymmetric version in case of the achiral pincer complex. Instead deboronation of arylboronic acid occurred very efficiently leaving the aryl bromide intact. 相似文献
187.
Sureshbabu Ram Kumar Pandian Venkatraman Deepak Kalimuthu Kalishwaralal Jeyaraj Muniyandi Neelamegam Rameshkumar Sangiliyandi Gurunathan 《Colloids and surfaces. B, Biointerfaces》2009,74(1):266-273
Polyhydroxyalkanoates (PHAs) are natural, biodegradable polymers accumulated by bacteria under nutritional exhausted condition where carbon source is in excess. A gram positive bacterium (designated strain SRKP2) that potentially accumulated polyhydroxybutyrate (PHB) was isolated from dairy industrial waste. From its morphological and physiological properties and nucleotide sequence of its 16S rRNA, it was suggested that strain SRKP2 was similar to Brevibacterium casei. PHAs were synthesized from a medium containing dairy waste, yeast extract and sea water. The synthesized PHAs were characterized by FT-IR as Polyhydroxybutyrate (PHB). Response surface methodology was applied to optimize the production of PHB. From the optimized medium the yield of PHB was found to be 2.940 g/L. Here we report the direct use of dairy waste and sea water as potential sources for the production of PHB. Produced PHB was used to synthesize nanoparticles using solvent displacement technique. 相似文献
188.
Karthikeyan G Zambaldo C Barluenga S Zoete V Karplus M Winssinger N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):8978-8986
A concise and modular synthesis of pochonin?E and F, and their epimers at C-6 established the correct stereochemistry of these two natural products. Several members of the pochonin family have been shown to bind the heat shock protein?90 (Hsp90), which has been the focus of intense drug discovery efforts. Pochonin?E and F as well as their epimers were derivatized into the corresponding pochoximes and further modified at the C-6 position. Molecular dynamics simulations, docking studies, and Hsp90 affinity measurements were performed to evaluate the impact of these modifications. 相似文献
189.
N. Vijaya Subramanian Selvasekarapandian G. Hirankumar S. Karthikeyan H. Nithya C. S. Ramya M. Prabu 《Ionics》2012,18(1-2):91-99
The proton-conducting polymer electrolytes based on poly (N-vinylpyrrolidone) (PVP), doped with ammonium chloride (NH4Cl) in different molar ratios, have been prepared by solution-casting technique using distilled water as solvent. The increase in amorphous nature of the polymer electrolytes has been confirmed by XRD analysis. The FTIR analysis confirms the complex formation of the polymer with the salt. A shift in glass transition temperature (T g) of the PVP/NH4Cl electrolytes has been observed from the DSC thermograms which indicates the interaction between the polymer and the salt. From the AC impedance spectroscopic analysis, the ionic conductivity of 15?mol% NH4Cl-doped PVP polymer complex has been found to be maximum of the order of 2.51?×?10?5?Scm?1 at room temperature. The dependence of T g and conductivity upon salt concentration has been discussed. The linear variation of the proton conductivity of the polymer electrolytes with increasing temperature suggests the Arrhenius type thermally activated process. The activation energy calculated from the Arrhenius plot for all compositions of PVP doped with NH4Cl has been found to vary from 0.49 to 0.92?eV. The dielectric loss curves for the sample 85?mol% PVP:15?mol% NH4Cl reveal the low-frequency ?? relaxation peak pronounced at high temperature, and it may be caused by side group dipoles. The relaxation parameters of the electrolytes have been obtained by the study of Tan?? as a function of frequency. 相似文献
190.