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111.
Three analogues of 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO, 1) labelled with two (1-d2), five (1-d5) or seven (1-d7)2H were synthesized and used to trap the tert-butylperoxyl radical. The EPR spectra of 1-d2-OOBu(t) and 1-d7-OOBu(t) spin adducts exhibited more straightforward patterns and better signal to noise ratio than those obtained with 1 or 1-d5. The use of the easily available 1-d2 as spin trap could help significantly the analysis of the EPR signals when the signal of either superoxide or alkylperoxyl spin adduct is superimposed with the signals of other spin adducts. 相似文献
112.
Derek H. R. Barton Brigitte Charpiot Elise Tran Huu Dau William B. Motherwell Claudine Pascard Clotilde Pichon 《Helvetica chimica acta》1984,67(2):586-599
The syntheses and X-Ray analyses of three pentavalent organobismuth compounds are described; one of these compounds has a novel diphenylbis(trifluoroacetato)-bismuthate anion with trigonal bipyramidal geometry and a stereochemically active lone pair. Analysis of these structures together with other data from the literature allows a mapping of the reaction coordinate for bismuth polyhedra. 相似文献
113.
114.
Claudine Giacinti-Diebolt 《Mathematische Annalen》1984,266(3):321-350
Sans résumé 相似文献
115.
116.
Using an ab initio total energy approach, we study the stability of free and Ag(111)-supported MgO(111) ultrathin films. We unravel a novel microscopic mechanism of stabilization of polar oxide orientations, based on a strong modification of the MgO structural phase diagram with respect to the bulk material. We predict that, at low thickness, films which are either unsupported or deposited on Ag(111) display a graphitelike Bk structure rather than the expected rocksalt one. Our results provide a consistent interpretation of recent experimental findings, exemplify the efficiency of this novel stabilization mechanism, and suggest new methods to engineer oxide nanostructures. 相似文献
117.
Lehmann M Kestemont G Gómez Aspe R Buess-Herman C Koch MH Debije MG Piris J de Haas MP Warman JM Watson MD Lemaur V Cornil J Geerts YH Gearba R Ivanov DA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(11):3349-3362
Hexaazatrinaphthylene (HATNA) derivatives with six alkylsulfanyl chains of different length (hexyl, octyl, decyl and dodecyl) have been designed to obtain new potential electron-carrier materials. The electron-deficient nature of these compounds has been demonstrated by cyclic voltammetry. Their thermotropic behaviour has been studied by means of differential scanning calorimetry and polarised optical microscopy. The supramolecular organisation of these discotic molecules has been explored by temperature-dependent X-ray diffraction on powders and oriented samples. In addition to various liquid crystalline columnar phases (Col(hd), Col(rd)), an anisotropic plastic crystal phase is demonstrated to exist. The charge-carrier mobilities have been measured with the pulse-radiolysis time-resolved microwave-conductivity technique. They are found to be higher in the crystalline than in the liquid crystalline phases, with maximum values of approximately 0.9 and 0.3 cm(2) V(-1) s(-1), respectively, for the decylsulfanyl derivative. Mobilities strongly depend on the nature of the side chains. 相似文献
118.
[reaction: see text] A new solid-phase synthesis of quinolines based on a Friedl?nder-type reaction between the resin-bound azomethine 1b and ketones 2 is described. This cyclative cleavage approach affords quinolines 3a-f in 50-81% yields. The polymer-bound aniline equivalent is easily recycled and may be reused with comparable performance. 相似文献
119.
Subodh Bhatnagar Judith Polonsky Marc Vuilhorgne Thierry Prangé Claudine Pascard 《Tetrahedron letters》1982,23(49):5159-5162
Laurycolactone A and B are new quassinoids with a C18 basic skeleton isolated from the Vietnamese Simaroubaceae, Eurycoma longifolia Jack. The structure of Eurycomalactone, a C19 quassinoid isolated previously from the same plant, has been revised and shown to be . The structures have been established by spectral means and those of and confirmed by X-ray diffraction analysis. 相似文献
120.
Samuel Moukouri Claudine Noguera 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(Z1):198-200
We study the size dependence of the electronic and structural properties of small MgO, CaO and NaCl clusters (up to 12 atoms), thanks to a selfconsistent tight binding approach in which we treat electrostatic and covalent effects on the same level. We discuss the conditions under which the ionic charges get reduced and the interatomic distances are contracted or dimerized. 相似文献