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131.
132.
Amel Ben Slimane Kada Boukerma Maud Chabut Mohamed M. Chehimi 《Colloids and surfaces. A, Physicochemical and engineering aspects》2004,240(1-3):45-53
Polypyrrole-coated poly(vinyl chloride) powder particles (PPy-PVC) were prepared by the in-situ chemical polymerization of pyrrole in aqueous solutions in the presence of PVC powder particles using the method of Ouyang and Chan [Polymer 39 (1998) 1857] and characterized by inverse gas chromatography (IGC). By employing n-alkane, 1-heptene, chloroform and tetrahydrofuran molecular probes, the dispersive and acid–base components of the surface energy of the composite materials were estimated at infinite dilution. The values of the dispersive contribution to the surface energy (γSd), at 50 °C, range from 30.3 to 43.5 mJ/m2 for the composites, which is much lower than the value of 83.2 mJ/m2 obtained for para-toluene sulfonate-doped polypyrrole (PPyTS) bulk powder. This indicates that the injected molecules probe both polypyrrole and the underlying PVC, thus indicating that the conducting polymer is rather patchy at the surface of the insulating polymer substrate. This conclusion supports the previous results obtained by X-ray photoelectron spectroscopy (XPS) [19], indicating that both the coating PPyTS and the substrate PVC are detected by their elemental markers nitrogen and sulfur, and chlorine, respectively. 相似文献
133.
Meriam Boumedjout Amel Bendjeddou Lakhmici Kaboub Abdelkrim Gouasmia Didier Villemin 《Phosphorus, sulfur, and silicon and the related elements》2016,191(6):891-897
A new series of bis-fused tetrathiafulvalene containing functional groups was synthesized. The synthesis was carried out by using routes involving cross coupling, reduction, and oxidation reactions. The identity of these new donors is confirmed by 1 H NMR spectroscopy, mass spectrometry, and elemental analysis. We have used the cyclic voltammetry in order to determine the character π-donors of these molecules and to verify the reversibility of the redox process involved. Molecular orbital diagram has been calculated using density-functional calculations. Charge transfer complexes with tetracyanoquinodimethane (TNQ) were prepared by chemical redox reactions. 相似文献
134.
This paper is concerned with the severely ill-posed Cauchy–Stokes problem. We are interested in a data completion problem which is exploited to detect small leaks to control water loss Kim et al. (2008) [1]. This inverse problem is rephrased into an optimization one: An energy-like error functional is introduced. We prove that the optimality condition of the first order is equivalent to solving an interfacial equation which turns out to be a Cauchy-Steklov-Poincaré operator. Numerical trials highlight the efficiency of the method. 相似文献
135.
Nawel Khettache Amel Bendjeddou Malika Berredjem Zine Regainia Veronique Montero Chantal Menut 《合成通讯》2013,43(16):2299-2305
An efficient three‐step synthesis of chiral 1,1′‐(sulfonyl)bisaziridines is described. Preparation of these compounds was carried out easily starting from N,N′‐sulfonyl bis‐(α‐L‐aminoester) to afford the title compounds in very good yields. These 1,1′‐(sulfonyl)bisaziridines can constitute interesting synthetic building blocks. 相似文献
136.
In the paper entitled “Separation of representations with quadratic overgroups”, we defined the notion of quadratic overgroups, and announced that the 6-dimensional nilpotent Lie algebra g6,20 admits such a quadratic overgroup. There is a mistake in the proof. The present Erratum explains that the proposed overgroup is only weakly quadratic, and g6,20 does not admit any natural quadratic overgroup. 相似文献
137.
Amel Ben Othman Najah Cheriaa Rym Abidi Jacques Vicens Pierre Thury 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o859-o861
The title compound, C47H60O6·3CHCl3, is the first example of a lower‐rim mono‐ester calixarene derivative to be crystallographically characterized. The cone conformation adopted by the macrocycle is stabilized by three intramolecular hydrogen bonds. Self‐inclusion of the methyl ester chain in the cavity of an adjacent molecule gives rise to infinite chains parallel to the c axis. C—H⋯π interactions involving the methyl group most imbedded in the cavity contribute to the stabilization of the system. 相似文献
138.
139.
Summary The solvolysis of the title complex is slower in 0 to 70% v/v aqueous dioxan than in aqueous acetonitrile at 40, 45, 50 and 55° C, a fact that is attributed to the higher basicity and ionizing power of the latter solvent mixtures. The observed non-linearity for logk (solvolysis) versus 1/D plots was interpreted in terms of the relative stability of ground and transition state species. The calculated Gibbs free energy for transfer of the species in the transition state is consistent with the extreme stretching of the chlorinecobalt bond, a result which confirms the interchange dissociative mechanismI
d for the complex under study. 相似文献
140.
Summary The solvolysis of the title complex was investigated in water and in water +t-butanol mixtures in the 40 to 55°C range. The activation thermodynamic parameters were calculated and the extrema observed for H
and S
were compared with data obtained from the measured physical properties of the same solvent mixtures. The ethyl substituent in the pyridine rings manifests its effect on the activation entropy values and on the relatively low activation energies compared with the respective values obtained previously from the solvolysis oftrans-[Co(4-MePy)4Cl2]+ in the same media. The free energies of transfer of the cation were calculated in the ground and transition states. In the ground state, the ethyl and methyl substituents in the pyridine rings provide the complex cation with nearly equal stabilities. However, the effect of solvent on the cation stability is more pronounced in the transition state for the ethyl substituent. 相似文献