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31.
Mohamed Al Amine Benhacine Malika Hamadne Sofiane Bouacida Hocine Merazig 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(3):243-250
The oxalate dianion is one of the most studied ligands and is capable of bridging two or more metal centres and creating inorganic polymers based on the assembly of metal polyhedra with a wide variety of one‐, two‐ or three‐dimensional extended structures. Yellow single crystals of a new mixed‐metal oxalate, namely catena‐poly[[diaquasodium(I)]‐μ‐oxalato‐κ4O1,O2:O1′,O2′‐[diaquairon(III)]‐μ‐oxalato‐κ4O1,O2:O1′,O2′], [NaFe(C2O4)2(H2O)4]n, have been synthesized and the crystal structure elucidated by X‐ray diffraction analysis. The compound crystallizes in the noncentrosymmetric space group I41 (Z = 4). The asymmetric unit contains one NaI and one FeIII atom lying on a fourfold symmetry axis, one μ2‐bridging oxalate ligand and two aqua ligands. Each metal atom is surrounded by two chelating oxalate ligands and two equivalent water molecules. The structure consists of infinite one‐dimensional chains of alternating FeO4(H2OW1)2 and NaO4(H2OW2)2 octahedra, bridged by oxalate ligands, parallel to the [100] and [010] directions, respectively. Because of the cis configuration and the μ2‐coordination mode of the oxalate ligands, the chains run in a zigzag manner. This arrangement facilitates the formation of hydrogen bonds between neighbouring chains involving the H2O and oxalate ligands, leading to a two‐dimensional framework. The structure of this new one‐dimensional coordination polymer is shown to be unique among the AIMIII(C2O4)2(H2O)n series. In addition, the absorption bands in the IR and UV–Visible regions and their assignments are in good agreement with the local symmetry of the oxalate ligand and the irregular environment of iron(III). The final product of the thermal decomposition of this precursor is the well‐known ternary oxide NaFeO2. 相似文献
32.
Mohammed Benharrat Hocine Mokhtar-Kharroubi 《Rendiconti del Circolo Matematico di Palermo》2010,59(3):389-403
We consider an abstract optimal control problem with additional equality and inequality state and control constraints, we use the exterior penalty function to transform the constrained optimal control problem into a sequence of unconstrained optimal control problems, under conditions in control lie in L 1, the sequence of the solution to the unconstrained problem contains a subsequence converging of the solution of constrained problem, this convergence is strong when the problemis non convex, and is weak if the problemis convex in control. This generalizes the results of P.Nepomiastcthy [4] where he considered the control in the Hilbert space L 2(I,? m ). 相似文献
33.
34.
Zouaoui Setifi Fatima Setifi Lahcen El Ammari Malika El‐Ghozzi Jana Sopkov‐de Oliveira Santos Hocine Merazig Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):19-22
In the title compound, [Cu(C9H5N4O)Cl(C12H8N2)]n or [Cu(tcnoet)Cl(phen)]n, where phen is 1,10‐phenanthroline and tcnoet is 1,1,3,3‐tetracyano‐2‐ethoxypropenide, the axially elongated (4 + 2) coordination polyhedron around the CuII centre contains N atoms from three different tcnoet ligands. The resulting coordination polymer takes the form of sheets which are linked in pairs by a single C—H...N hydrogen bond to form bilayers. The bond lengths provide evidence for significant bond fixation in the phen ligand and extensive electronic delocalization in the tcnoet ligand, where the two –C(CN)2 units are rotated, in conrotatory fashion, out of the plane of the central C3O fragment. 相似文献
35.
Mohamed El Amine Dib Hocine Allali Amel Bendiabdellah Nawel Meliani Boufeldja Tabti 《Journal of Saudi Chemical Society》2013,17(4):381-385
In this study, antimicrobial activities of water and methanol extract, and three phenolic fractions of the roots of Arbutus unedo L. were investigated. Poor antibacterial activity against both Staphylococcus aureus and Pseudomonas aeruginosa bacteria was shown with water and methanol extract. However moderate antibacterial activity was shown by water extract and phenolic fractions against Escherichia coli and S. aureus, respectively. The phytochemical screening of roots of A. unedo revealed the presence of quinones, anthraquinones reducteurs compounds, anthocyanins, tannins and flavonoids. Quantitative analysis showed that the roots were strongly dominated by anthocyanins compounds (3.65 mg g?1) followed by total flavonoids (0.56 mg?1) and flavones & flavonols (0.17 mg g?1). 相似文献
36.
Sma?n Hocine Chérifa Rabia Mohammed M. Bettahar Michel Fournier 《Reaction Kinetics and Catalysis Letters》2003,79(2):357-364
Cs2.5M0.08H0.26PMo12O40and Cs2.5M0.08H1.26PMo11VO40(M: Ni, Fe) heteopolyanions were selectively prepared, characterized by IR, Raman, 31P NMR, XPS and XRD and tested in the ODH of cyclohexane. The salt structure, and reaction mechanism and kinetics are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
37.
Mebarek Hocine Hadjoui Abdelhamid 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(6):573-597
The hp-version of the finite element method based on a triangular p-element is applied to free vibration of the orthotropic triangular and rectangular plates. The element's hierarchical shape functions, expressed in terms of shifted Legendre orthogonal polynomials, is developed for orthotropic plate analysis by taking into account shear deformation, rotary inertia, and other kinematics effects. Numerical results of frequency calculations are found for the free vibration of the orthotropic triangular and rectangular plates with the effect of the fiber orientation and plate boundary conditions. The results are very well compared to those presented in the literature. 相似文献
38.
Mössbauer spectroscopy can be a useful structural tool to assist crystallographic methods for site assignment when the compound under investigation contains divalent tin. The goal of this work was to show that the structure of tin(II) fluoride, also know as stannous fluoride, SnF2, could have been solved 14 years earlier if Mössbauer spectroscopic results, already known, had been used. A first attempt to solve the crystal structure, carried out by Bergerhoff in 1962 seemed to find the tin positions, however, it failed to find the positions of fluorine. Further extensive studies by Dénès et al. in the mid 1970s yielded the same results as those of Bergerhoff, despite the use of a Nonius CAD-4 automatic diffractometer, in contrast with Bergerhoff’s film work. The tin positions yielded a residual of 0.23, and Fourier difference maps showed significant electron density that could be fluorine atoms, however, their number did not match the number of fluorine atoms expected and several F-F distances were way too short. In addition, refinement using these possible fluorine positions led to no improvement of the residual factor. Finally, the crystal structure was published by McDonald et al. in 1976. It was found that the tin sublattice determined by Bergerhoff was basically correct, except that half of the tin atoms found by Bergerhoff to be on the (4b) and (4e) special Wyckoff sites were actually on the (8f) general site. A translation of the origin of the unit-cell by the [1/8, 0, 3/16] vector allows to change the tin Wyckoff sites from (4b), (4e) and (8f) to two (8f) sites, while keeping the basic spatial distribution of tin. A method has now been designed, using 119Sn Mössbauer spectroscopy, to test the suitability of some Wyckoff sites for divalent tin, using the Mössbauer spectrum. The tin(II) doublet (δ = 3.430(3) mm/s, Δ = 1.532(3) mm/s) shows that the lone pair is on a hybrid orbital, therefore, it is stereoactive, and it results that tin cannot be on either the (4b) or (4e) tin site since both an inversion center and a 2-fold axis would generate a second lone pair unless the 2-fold axis were along the tin-lone pair axis. 相似文献
39.
Faouzi Guenadil Hocine Aichaoui Coco N. Kapanda Didier M. Lambert Christopher R. McCurdy Jacques H. Poupaert 《Monatshefte für Chemie / Chemical Monthly》2011,27(7):67-80
Abstract
A simpler and efficient “green” method using solid sodium hydroxide in a solvent mixture of acetone/water was found to catalyze N-acylation of 2(3H)-benzoxazolones and 2(3H)-benzothiazolones for facile and rapid synthesis of N-acyl derivatives in excellent yields. This method was applied to the synthesis of a series of 132 compounds employing a variety of acyl chlorides. 相似文献40.
Ammonium salts, (NH4)6HPMo11MO40 (M = Ni, Co, Fe), have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 °C and 420 °Cafter in-situ pre-treatment performed at two heating rate of 5 or 9 °C/min. They were characterized by BET method, XRD, 31P NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 °C/min. 相似文献