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The systematic preparation of partially fluorinated pentafluorosulfur alkanes containing no additional halogens is reported. Thus, the indirect addition of “HF” (via KF/formamide) to SF5CH=CF2, SF5CFCF2, and SF5C(CF3)CF2 produces SF5CH(in2)CF3, SF5CHFCF3, and SF5C(CF3)2H respectively. The monohydryl-pentafluorosulfur-F- alkanes react readily with S2O6F2 to form the corresponding fluorosulfates by oxidative displacement of hydrogen, while the dihydryl derivative undergoes cleavage to produce F-acetyl fluoride. Efforts to convert some of the new materials to the important but unknown pentafluorosulfur “ketone,” SF5C(O)CF3, were unsuccessful. 相似文献
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The crystal structure of p-nitrostyrene oxide has been determined at room temperature from three-dimensional X-ray diffractometer data, and refined by full-matrix least-squares to a final R = 0·045. The crystals are monoclinic, space group P21/c with unit-cell dimensions a = 7·8244(2), b = 7·1277(2), c = 14·2059(4) Å, β = 104·193(3)°. The value of the dihedral angle formed by the phenyl ring and the oxirane ring (80·2°) can be rationalised on the basis of pseudoconjugation between the two rings, and of non-bonding interactions of one of the ortho-hydrogens of the phenyl ring with the hydrogens of the oxirane ring. The oxirane ring contains a short CC bond of length 1·448(4) Å. 相似文献
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Amorati R Ferroni F Lucarini M Pedulli GF Valgimigli L 《The Journal of organic chemistry》2002,67(26):9295-9303
A systematic investigation is reported on the regeneration of alpha-tocopherol (alpha-TOH) in homogeneous solution by coantioxidants in order to better understand the mechanism and the factors responsible for the effectiveness of this process. The current availability of thermochemical data concerning the reactants involved in the regeneration reactions, as well as a large number of the kinetic constants for the various reactions involved, allowed us to rationalize the experimental observations collected so far. Three limiting cases have been considered. The first case is that of a coantioxidant irreversibly regenerating alpha-TOH, where the effectiveness of the recycling process depends on the magnitude of the rate constant k(r). The second case is that of a coantioxidant reversibly recycling alpha-TOH, where regeneration can only be observed if the bond dissociation enthalpy value of the coantioxidant is lower or at least close to that of the O-H bond of alpha-tocopherol. The third case is that of a catechol derivative (chosen as a model compound for polyphenolic antioxidants), where recycling of alpha-TOH is feasible even though the BDE value is significantly higher than that of vitamin E. In this case, the driving force for the recycling process is the removal of the semiquinone radical from the catechol derivative by the alpha-tocopheroxyl radical, which makes the regeneration of alpha-TOH practically irreversible. 相似文献
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Exploring the Molecular Structure of Imidazolium–Silica‐Based Nanoparticle Networks by Combining Solid‐State NMR Spectroscopy and First‐Principles Calculations 下载免费PDF全文
Dr. Marie‐Alexandra Neouze Martin Kronstein Dr. Marco Litschauer Dr. Michael Puchberger Dr. Cristina Coelho Prof. Christian Bonhomme Prof. Christel Gervais Dr. Frederik Tielens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15188-15196
A DFT‐based molecular model for imidazolium–silica‐based nanoparticle networks (INNs) is presented. The INNs were synthesized and characterized by using small‐angle X‐ray scattering (SAXS), NMR spectroscopy, and theoretical ab initio calculations. 11B and 31P HETCOR CP MAS experiments were recorded. Calculated 19F NMR spectroscopy results, combined with the calculated anion–imidazolium (IM) distances, predicted the IM chain density in the INN, which was also confirmed from thermogravimetric analysis/mass spectrometry results. The presence of water molecules trapped between the nanoparticles is also suggested. First considerations on possible π–π stacking between the IM rings are presented. The predicted electronic properties confirm the photoluminescence emissions in the correct spectral domain. 相似文献
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