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11.
Irene Ara Fatima El Bahij Mohamed Lachkar Najib Ben Larbi 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):m107-m108
A new triclinic polymorphic modification of the title compound, [Ag(C3H5OS2)(C18H15P)2], has been found and compared with the previously known orthorhombic modification [Tiekink (1988). Coord. Chem. 17 , 239–243]. The two polymorphs have the same molecular shape, viz. a distorted tetrahedral geometry, with a chelating dithiocarbonate (xanthate) and two PPh3 ligands bonded to the Ag atom. However, in this new polymorph, the xanthate ligand is bonded asymmetrically to the Ag atom, with Ag—S distances of 2.5489 (6) and 2.8055 (7) Å, while for the orthorhombic polymorph these distances are 2.686 (4) and 2.601 (4) Å. The Ag—P distances are similar in both structures. 相似文献
12.
The facile preparation of N(H)-bridged azacalix[4]arenes has been achieved by stepwise nucleophilic aromatic substitutions assisted by hydrogen bonding interactions. The synthesis is uncatalyzed and affords previously unknown tetranitroazacalix[4]arenes. 相似文献
13.
Rachid Essehli Brahim El Bali Aziz Alaoui Tahiri Mohammed Lachkar Bouchaib Manoun Michal Duek Karla Fejfarova 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(12):i120-i124
The crystal structures of three isotypic orthorhombic dihydrogendiphosphates, namely dipotassium copper(II)/nickel(II)/zinc(II) bis(dihydrogendiphosphate) dihydrate, K2M(H2P2O7)2·2H2O (M = Cu, Ni and Zn), have been refined from single‐crystal data. The M2+ and K+ cations are located at sites of m symmetry, and the P atoms occupy general positions. These compounds also exist in triclinic forms with very similar structural features. The structures of both forms are compared, as well as the geometry of the MO6 octahedron, which is considerably elongated towards the water molecules for M = Ni and Cu. Such elongation has not been observed among the other representatives of the family. A Raman study of the whole series K2M(H2P2O7)2·2H2O (M = Mn, Co, Ni, Cu, Zn and Mg) is reported. 相似文献
14.
Ara Irene El Bahij Fatima Lachkar Mohamed Ben Larbi Najib 《Transition Metal Chemistry》2003,28(8):908-912
Monomeric, five-coordinated bis(ethylxanthato)ZnII(phosphine) complexes [phosphine = PPh3, P(o-tolyl)3, P(CH2Ph)3] have been synthesized by addition of the phosphine ligand (1:1 molar ratio) to CH2Cl2 solutions of [Zn(S2COEt)2]. Bidentate ligands Ph2PCH2CH2PPh2 (dppe) and Ph2P(CH2)4PPh2 (dppb) reacted in a 1:2 molar ratio to form dinuclear phosphine-bridged complexes. The Zn—P bonds are very labile and are probably broken in solution. The characterization of all the compounds has been carried out by elemental analyses and spectroscopic methods (i.r. and n.m.r.). The structure of binuclear [(S2COEt)2Zn(-dppb)Zn(S2COEt)2], determined by X-ray crystallography, shows a distorted trigonal bipyramidal environment for the Zn atoms, formed by two chelating xanthate and a bridging dppb ligand. 相似文献
15.
R. Essehli A. Lamhamdi A. Tahiri Alaoui B. El Bali E. Mejdoubi M. Lachkar M. Dusek K. Fejfarova 《Journal of chemical crystallography》2012,42(5):475-485
Abstract
New diphosphates AErP2O7, A = Rb (1), Cs (2), and HEuP2O7·3H2O (3) have been prepared via soft chemistry route from evaporation of aqueous solution. Their crystal structures have been solved by single crystal diffraction data. The compounds (1) and (2) crystallize in the monoclinic space group P21/c with the following unit cell dimensions: (1) a = 7.7248(4) ?, b = 10.9342(6) ?, c = 8.6716(3) ?, β = 105.434(4)° and Z = 4; (2) a = 7.9192(4) ?, b = 10.8606(4) ?, c = 8.7684(5) ?, β = 104.317(5)° and Z = 4. Compound (3) crystallises in the triclinic space group P − 1, with the unit cell parameters: a = 6.4036(5) ?, b = 6.8753(6) ?, c = 9.7964(8) ?, α = 81.706(7)°, β = 80.218(7)°, γ = 88.381(7)°. Crystal structure of (1) and (2) consists of 3D open framework built from [ErO6] octahedra sharing corners with [P2O7] units, leading to the formation of channels running along c direction in which A+ [A = Rb(1), Cs(2)] ions are located. The compound (3), on the other hand, exhibits a lamellar structure, in which edge-sharing polyhedra of eightfold coordinated europium form chains along [010]. These chains are joined in turn to each others using diphosphates bridges. A network of O–H···O hydrogen bonds reinforces the cohesion of the structure of (3). The diphosphate groups in (1), (2) and (3) adopts an eclipsed configuration. IR and Raman spectra of the three new phosphates show usual signals related to the P2O7 diphosphate group and the water molecule. TG and DTA studies were carried out on crystals of (3). The data are correlated to the crystal structures ones. 相似文献16.
New picket porphyrins delivering at least one carboxylic group around the coordination site of the macrocycle were synthesized for bismuth coordination. The influence of the number, the length, and the pre-organization of the carboxylic acid pickets on the stability of the bismuth complexes was explored. Their stabilities in acidic medium were compared with those of their precursors bearing ester pickets. The molecular structure of one of the bismuth complexes, which is the only monomeric bismuth porphyrin reported up to now, is discussed. At the opposite of what we initially reported, and in agreement with the theoretical calculations, the distortion of the macrocycle in this structure is mainly due to the number of water molecules in the first sphere of coordination of the bismuth. 相似文献
17.
Machkour A Thallaj NK Benhamou L Lachkar M Mandon D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(25):6660-6668
Coordination of FeCl3 to the title ligand yields a mononuclear iron(III) complex 1, which was characterized by spectroscopic techniques and X-ray diffraction. The ligand is (kappa3-N) tridentate and the metal, which lies in a pseudo-octahedral environment, is bound to a phenolate group from the catechol substituent. The dichloroiron(II) complex 2 was easily obtained by metalation of the ligand with FeCl2 and characterized by various spectroscopic techniques. In their cyclic voltammograms both 1 and 2 display the same reversible FeII/FeIII wave at E1/2=10 mV (vs. SCE). Reduction of compound 1 with Zn/Hg yields 2', which displays identical properties to 2. Taken together, these findings indicate that in spite of the different oxidation state of the metal in 2, no major geometrical/structural change is observed at the metal center with respect to 1. The reaction of 2 with dioxygen in the absence of organic substrates proceeds extremely rapidly and yields compound 3, which is a diiron(III) derivative whose X-ray crystal structure is also reported. The possibility of a radical-based mechanism is discussed. Compound 3 displays an unusual geometry: one iron(III) center is seven-coordinate, whereas the other lies in a square-pyramidal environment. The two iron atoms are bridged by the catecholato substituents. To the best of our knowledge, 3 is the first example of a seven-coordinate iron(III) derivative with tris(2-pyridylmethyl)amine ligands. 相似文献
18.
El Antri A Messouri I Tlemçani RC Bouktaib M El Alami R El Bali B Lachkar M 《Molecules (Basel, Switzerland)》2004,9(7):568-573
The known flavonoid chrysin-7-O-(beta-D-glycopyranoside) (chrysin glucoside,1) as a major fraction and a new glycoside flavone, chrysin-7-O-beta-D-[(6"-acetyl)glycopyranoside] (2) were isolated from the flowers and leaves of Calycotome Villosa Subsp. Intermedia, They were identified by UV-Vis, 1R, (1)H-, (13)C-NMR and ESI-MS. 相似文献
19.
Irene Ara Fatima El Bahij Mohamed Lachkar Najib Ben Larbi 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(5):m199-m200
The Pd atom in the title compound, [Pd(C3H5OS2)2], lies on an inversion center and adopts a square‐planar coordination geometry defined by the four S atoms of the two dithiocarbonate (xanthate) ligands. In the solid state, the molecules aggregate into layers in which the rows of molecules alternate their orientation to allow each Pd atom to interact with two symmetry‐equivalent S atoms of the xanthate ligands of adjacent molecules, generating a pseudo‐octahedral environment around each Pd atom. This weak interaction of 3.3579 (7) Å can be classified as a closed‐shell electrostatic intermolecular interaction. 相似文献
20.
Ali El Antri Nadya Lachkar Hanane El Hajjaji Farah Gaamoussi Badiaa Lyoussi Brahim El Bali Nicole Morel Hassan Allouchi Mohammed Lachkar 《Arabian Journal of Chemistry》2010,3(3):173-178
Two flavonols identified as 3,5,7,4′-tetrahydroxy-3′-methoxyflavone (1) and 3,5,7,4′-tetrahydroxy-8-methoxyflavone (2) were isolated from the seeds of Calycotome villosa subsp. intermedia. The structure elucidation of the isolated compounds was performed by the spectroscopic methods (UV, IR, 1H NMR, 13C NMR and MS) and also by a single crystal X-ray analysis in the case of compound (2). Vasodilator activity of compound (2) was demonstrated in isolated rat aorta contracted with high KCl or with noradrenaline. 相似文献