JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Elaboration et caractérisation des hybrides "organiques-inorganiques" du polyméthylhydrosiloxane réticulé par des oléfines synthétisées

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Reactions of allylbromide with benzene-1,2,4,5-tetracarboxydiimide (BTCD) and hydroquinone in different solvents are carried out. They lead to the formation of N,N'-diallylbenzene-1,2,4,5-tetracarboxydiimide (N,N'DBTCD) and 1,4-bis(prop-2-enyloxy)benzene (BPEB) that have been characterized by infrared, 1H NMR and 13C NMR, The polymethylhydrosiloxane (P.M.H.S) is modified by these prepared organic olefines. The mixtures of reactants under appropriate proportions and conditions, lead to the formation of polymeric gels. These materials have been characterized by Infrared, 1H NMR, 13C NMR and Scanning Electronic Microscopy (S.E.M).

F. Sediri, N. Etteyeb, N. Gharbi

Pages 1479-1488

Etude des complexes des N-thioamidoiminoesters avec Ag(I) dans l’acétonitrile

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Potentiometric studies on silver(I) complexes of N-thioamidoiminoesters in acetonitrile are described. Stability constants of silver(I) complexes with N-thioamidoiminoesters are determined by potentiometric titration using a silver electrode. Stability constant values obtained by graphical methods are refined by statistical methods. With Ag(I), N-thioamidoirninoesters gives three complexes.

A. Cherni, M.L. El Efrit, H. Zantour, M. Dachraoui

Potentiometry, acetonitrile, Ag(I), N-thioamidoirninoesters, complexes, simulation

Pages 1489-1495

Cinétique et thermodynamique de la σ-complexation du 2-(4’-nitrophényl)-4,6-dinitrobenzotriazole1-oxyde en solution aqueuse

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Rate and equilibrium constants for the σ-complexation of 2-(4'-nitropheny1)-4,6- dinitrobenzatriazole 1-oxide (2a) have been mesured over a large pH range in aqueous solution. The pKa value for the formation of the expected hydroxy σ-complex 4a is equal to 9.00±0.03, pointing out that this species is more stable than all related σ-adducts previously studied in benzene, naphthalene or pyridine series. In contrast 4a is 2 x 105 times less stable than the hydroxy σ-adduct of 4,6-dinitrobenzofuroxan (DNBF). This indicates that the electrophilicity of 2a is remarkable without being as exceptional as that of DNBF. This conclusion is supported by the finding that water addition to 2a is a rather negligible process in the formation of 4a. Also, the susceptibility of 2a to hydroxide ion attack is 50 times lower than that of DNBF. Reasonable mechanisms for the formation of the adduct 4a are discussed on the basis of the observed buffer catalysis and deuterium isotope effects.

T. Boubaker, A.P. Chatrousse, B. Tangour, F. Terrier

Benzotriazoles,σ-adduits, Substitutions Nucloophiles Aromatiques, Cinetique de σ-complexation, Superelectrophiles

Pages 1497-1507

Préparation, caractérisation par spectroscopie d’absorption IR. Etude structurale et analyse thermique du complexe dinucléaire de cuivre(II) (diaquo éthyléneglycol) bis(amino-2 éthyléther) N,N-tétraacétato), dihydrate [CU2(C14H20N2O10).2H2O].2H2O

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The complex [Cu2(C14H20N2O10).2H2O].2H2O crystallizes in the monoclinic system of space group C2/c. The cell parameters are: a=20.984(2), b=7.530(1), c=13.558(2) A, β=90.79(1)° and Z=4. The structure is built up from [Cu2(C14H20N2O10).2H2O] molecules and water molecules. The coordination sphere around each Cu(II) atom is square pyramidal. The oxygen atoms of deprotonated hydroxyl groups, one nitrogen atom of the ligand and one water molecule are in the base meanwhile another oxygen atom of the same ligand is in apical position. Complex molecules are interconnected by O-H...O hydrogen bonds to form a three dimensional framework. The compound is characterized by I.R. absorption. The thermal analysis shows that four water molecules are needed for building the complex.

F. Ben Amor, M. Krimi Ammar, T. Jouini, A. Driss

complex, copper(II), structure, I.R. absorption, thermal analysis

Pages 1525-1533

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