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171.
A multicomponent reaction for the synthesis of fused azo‐linked pyrazolo[4,3‐e]pyridines from 3‐amino‐5‐methylpyrazole, indan‐1,3‐dione and synthesized azo‐linked aldehydes using nano‐Fe3O4 as an effective and reusable catalyst is reported. The present methodology offers several advantages, such as a simple procedure with an easy work‐up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents. 相似文献
172.
Farshid Ramezanipour Bradley Cowie Shahab Derakhshan John E. Greedan Lachlan M.D. Cranswick 《Journal of solid state chemistry》2009,182(1):153-3227
The crystal and magnetic structures of the brownmillerite material, Ca2Fe1.039(8)Mn0.962(8)O5 were investigated using powder X-ray and neutron diffraction methods, the latter from 3.8 to 700 K. The compound crystallizes in Pnma space group with unit cell parameters of a=5.3055(5) Å, b=15.322(2) Å, c=5.4587(6) Å at 300 K. The neutron diffraction study revealed the occupancies of Fe3+ and Mn3+ ions in both octahedral and tetrahedral sites and showed some intersite mixing and a small, ∼4%, Fe excess. While bulk magnetization data were inconclusive, variable temperature neutron diffraction measurements showed the magnetic transition temperature to be 407(2) K below which a long range antiferromagnetic ordering of spins occurs with ordering wave vector k=(000). The spins of each ion are coupled antiferromagnetically with the nearest neighbors within the same layer and coupled antiparallel to the closest ions from the neighboring layer. This combination of intra- and inter-layer antiparallel arrangement of spins forms a G-type magnetic structure. The ordered moments on the octahedral and tetrahedral sites at 3.8 K are 3.64(16) and 4.23(16) μB, respectively. 相似文献
173.
Two amino acid-based alkenoxy micelle polymers were synthesized for this study. These include polysodium N-undecenoxy carbonyl-L-leucinate (poly-L-SUCL) and polysodium N-undecenoxy carbonyl-L-isoleucinate (poly-L-SUCIL). The polymerization time and concentration of the synthesized micelle polymers were optimized by (1)H-nuclear magnetic resonance (NMR) and capillary electrophoresis (CE) experiments. Detailed physicochemical properties ((1)H NMR, critical micelle concentration (CMC), optical rotation, partial specific volume, aggregation number, and polarity) were determined, and these molecular micelles were introduced as a pseudostationary phase in micellar electrokinetic chromatography to study the molecular recognition and to develop a method for simultaneous separation of eight chiral beta-blockers. It is found that poly-L-SUCL gives overall better chiral resolution and wider chiral window than poly-L-SUCIL. After optimizing the type of micelle polymer, injection size and temperature, simultaneous separation and enantioseparation of eight beta-blockers were achieved in less than 35 min. A comparison with the amide-type surfactants of the same polar head group and alkyl chain length showed that carbamate-type surfactants always work better than the corresponding amide-type surfactant. 相似文献
174.
Sulfonic acid groups were grafted onto three different types of synthesized magnetic nanoparticles, namely Fe3O4, Fe3O4@SiO2, and Fe3O4@MCM‐48. The sulfonic acid‐functionalized nanoparticles were evalu... 相似文献
175.
Comparative study of photoionization of atomic hydrogen by solving the one-and three-dimensional time-dependent Schr(o)dinger equations 下载免费PDF全文
We develop a numerical scheme for solving the one-dimensional (1D) time-dependent Schr(o)dinger equation (TDSE),and use it to study the strong-field photoioniza... 相似文献
176.
Mehdi Ghandi Shahab Sheibani Masoud Sadeghzadeh Fariba Johari Daha Maciej Kubicki 《Journal of the Iranian Chemical Society》2013,10(6):1057-1065
An efficient catalyst-free and diastereoselective synthesis of novel dihydropyrano[2,3-d]pyrimidine and dihydropyrano[3,2-c]chromen-annulated benzosultams is described. A number of (E)-N-(2-formylphenyl)-N-methyl-2-phenylethenesulfonamides were synthesized and underwent a one-pot domino Knoevenagel hetero-Diels–Alder reaction, respectively, with N,N-dimethylbarbituric acid and 4-hydroxycoumarin in water, giving the desired products, in moderate to excellent yields. 相似文献