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21.
Jetti RK Thallapally PK Nangia A Lam CK Mak TC 《Chemical communications (Cambridge, England)》2002,(9):952-953
The title molecule forms a honeycomb network of molecular and nitro-trimer synthons with guest species included in the hexagonal voids. 相似文献
22.
Sumod George Ashwini Nangia Vincent M. Lynch 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):777-778
In the crystal structure of the title compound, C13H12N2O, N—H(anti)?O hydrogen bonds produce the so‐called urea α‐network and the N—H(syn) donor forms an unconventional N—H?π hydrogen bond. 相似文献
23.
V. S. Senthil Kumar Ashwini Nangia 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):123-124
The title compound, C36H26O2Se2, displays crystallographic twofold symmetry. The packing involves corrugated linear ribbons mediated through C—H?O and C—H?Se interactions. The ribbons are connected through C—H?π interactions. 相似文献
24.
A T6(2) tape of hydrogen bonded water molecules in boat cyclohexane conformation resides in the channel structure of a dibromophloroglucinol (DBPG) host; water escapes at 40-90 degrees C but is readily re-absorbed by the sponge-like apohost. 相似文献
25.
Morpholine is a base of moderate strength, comparable with that of ammonia, and capable of forming -onium-type salts. Extensive studies [1,2] have been made on the thermal stability of ammonium perchlorate because of its technological use as an oxidant in solid state rocket propellants. The preparation, characterization and thermal behaviour of morpholinium perchlorate are reported in this note. The study was followed by XRD, IR, TG, DTA and mass spectral techniques. 相似文献
26.
27.
Bitupon Borthakur Prof. Ashwini K. Phukan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11603-11609
The effect of ylide substitution at the α position to the carbene carbon (Cc) atom on the stability and σ‐donating ability of a number of cyclic carbenes has been studied theoretically. The stabilities of all of the carbenes were investigated from an evaluation of their singlet–triplet energy gaps and stabilization energies. All carbenes were found to have a stable singlet state. The energy of the σ‐symmetric lone‐pair orbital at the Cc atom increases as a result of the introduction of ylide centers near to the Cc atom. This indicates an enhanced σ‐donating ability of the ylide‐containing carbenes. The calculated carbonyl‐stretching frequencies of the corresponding rhodium complexes, proton affinities, and nucleophilicity index values correlate well with the σ basicity of the carbenes. 相似文献
28.
Benjamin Rudshteyn Álvaro Castillo Ashwini A. Ghogare Joel F. Liebman Alexander Greer 《Photochemistry and photobiology》2014,90(2):431-438
Photobiologic and synthetic versatility of hydrazones has not yet been established with 1O2 as a route to commonly encountered nitrosamines. Thus, to determine whether the “parent” reaction of formalhydrazone and 1O2 leads to facile C=N bond cleavage and resulting nitrosamine formation, we have carried out CCSD(T)//DFT calculations and analyzed the energetics of the oxidation pathways. A [2 + 2] pathway occurs via diradicals and formation of 3‐amino‐1,2,3‐dioxazetidine in a 16 kcal/mol?1 process. Reversible addition or physical quenching of 1O2 occurs either on the formalhydrazone carbon for triplet diradicals at 2–3 kcal mol?1, or on the nitrogen (N(3)) atom forming zwitterions at ~15 kcal/mol?1, although the quenching channel by charge‐transfer interaction was not computed. The computations also predict a facile conversion of formalhydrazone and 1O2 to hydroperoxymethyl diazene in a low‐barrier ‘ene’ process, but no 2‐amino‐oxaziridine‐O‐oxide (perepoxide‐like) intermediate was found. A Benson‐like analysis (group increment calculations) on the closed‐shell species are in accord with the quantum chemical results. 相似文献
29.
In this paper, a highly selective Sudan IV molecularly imprinted polymer was synthesized by surface molecular imprinting technique in combination with a sol?Cgel process using ??-aminopropyl triethoxysilane as functional monomer, tetraethoxysilane as cross-linker and activated silica gel as support material. The imprinted polymer was characterized by FT-IR spectra, scanning electron micrograph and adsorption experiments and it was exhibited good recognition and selective ability, offered a faster rate for the adsorption of Sudan IV. Using the imprinted material as sorbent, a solid-phase extraction coupled with high-performance liquid chromatography method for determination of trace Sudan IV was presented. The detection limit (S/N = 3) was 25.2 ng L?1, and the RSD for five replicate was 2.86%. With a loading flow rate of 2.5 mL min?1 for loading 30 mL, an enrichment factor of 104 was achieved. This method was applied for extraction and determination of chilli powder and duck egg samples with good recoveries ranging from 85.3 to 98.1%. 相似文献
30.
Givelet C Sun J Xu D Emge TJ Dhokte A Warmuth R 《Chemical communications (Cambridge, England)》2011,47(15):4511-4513
Several dynamic hexaimine cryptophanes, that are built up from two triformylcyclotribenzylene cavitands and three diamino linkers and spontaneously assemble in water in the presence of a suitable templating guest, are reported. X-ray structure, kinetics and thermodynamics of assembly and molecular recognition properties are discussed. 相似文献