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Dimethylphosphoramides react with -chloroperoxybenzoic acid (MCPBA) in anhydrous acetone to yield the previously unknown -dimdethylamino-oxyphosphonous derivatives -oxidation and rearrangement. Further MCPBA oxidation yields formaldehyde and nitrosomethane, isolated as its -dimer. These reactions provide a possible biomimetic model for the metabolic activation of hexamethylphosphoramide as a mutagen and carcinogen. 相似文献
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Superoxide generated in DMF readily converts the dihalovinyl group of permethrin and related compounds to a haloethynyl moiety and yields major products from elimination reactions of DDT, -chlordane, and 1,2-dibromo-3-chloropropane (DBCP). 相似文献
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Yoffi Segall John E. Casida 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):209-212
Abstract S-Oxide 2 is an extremely reactive intermediate. Its phosphorylation vs rearrangement rates, strongly depend upon the nature of the nucleophile. 相似文献
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Bulk superconducting samples of type Tl0.5Pb0.5Sr1.6Ba0.4CaCu2−x
Ru
x
O7−δ, (Tl, Pb)/Sr-1212, with 0.0 ≤ x ≤ 0.525 were prepared by the conventional one-step solid-state reaction technique. The prepared samples were investigated
using X-ray powder diffraction, electrical resistivity and electron paramagnetic resonance (EPR) measurements. Enhancement
of the phase formation, superconducting transition temperature T
c and hole carriers concentration P was observed up to x = 0.075. For x > 0.075, a reverse trend was observed. EPR spectra were measured at different temperatures (120–290 K) for all prepared samples.
The number of spins N participating in the resonance and the paramagnetic susceptibility χ were calculated as a function of both Ru-content and
temperature. N and χ increased as the Ru-content increased. A linear relationship between logN and 1/T was established, from which the activation energy E
a was calculated as a function of the Ru-content. The temperature dependence of χ was fitted according to Curie–Weiss type
of magnetic behavior. Curie constant C, Curie temperature θ, the effective magnetic moment μ and the electronic specific heat γ were estimated as a function of the Ru-content. 相似文献
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ABSTRACTBayfol (PC-PBT blend ?lm) is a class of polymeric solid-state nuclear track detector which has a lot of applications in several radiation detection ?elds. It is a bisphenol-A polycarbonate PC blended with polybutylene terephthalate PBT. Bayfol/Palladium (PC-PBT/Pd) nanocomposite films have been deposited using the molding technique. It is worth mentioning that this report is almost the first one dealing with the topic of the changes of physical properties of Bayfol/Pd nanocomposite due to laser exposure. Samples from PC-PBT/Pd (5?wt%) nanocomposite were exposed to IR-pulsed laser of 5-W power, capable of producing 2000 pulses per second with pulse duration of 200?ns at 904?nm. The laser fluences were in the range 2–25?J/cm2. The resultant modi?cations in the exposed nanocomposite samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction (XRD), UV spectroscopy and color difference studies. The results indicate the proper dispersion of Pd nanoparticles in the PC-PBT matrix that causes a strong intermolecular interaction between Pd and PC-PBT, resulted in an increase in refractive index and the amorphous phase. Also, it is found that the laser exposure reduces the optical energy gap that could be attributed to the increase in structural disorder of the exposed PC-PBT/Pd nanocomposites due to crosslinking. Further, the color intensity ΔE, which is the color difference between the exposed samples and the non-exposed one, was increased with increasing the laser fluence, convoyed by a significant increase in the green and yellow color components. 相似文献
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Mark Casida 《International journal of quantum chemistry》1985,27(4):451-460
The usefulness of the notion that a one-particle reduced local energy map can measure local errors in a trial wave function is investigated. Examination of the literature suggests that this notion rests on the assumption that a map of the relative error in the one-particle density behaves like the one-particle reduced local energy map. This is tested for several spinless one-dimensional one-particle systems. The assumption is discovered to be ill founded when applied to a certain contrived situation, and not to be quantitative when applied to familiar situations. The possibility remains, however, that the assumption may sometimes be useful for obtaining the correct ordering of trial wave functions with respect to the accuracy of certain types of expectation values. 相似文献