Etude,par thermogravimétrie et spectrographie d'absorption infrarouge,de quelques sulfates doubles de la série magnésienne. I. Courbes de thermolyse

Résumé L'auteur étudie le comportement thermique des sulfates doubles du type M₂M(SO₄)₂ · 6 H₂O, avec M=K et NH₄ et M=Ni, Co, Mg, Zn et Fe.

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Summary A study was made of the thermal behavior of double sulfates of the type M₂M(SO₄)₂ · 6 H₂O where M=K or NH₄ and M=Ni, Co, Mg, Zn, Fe.

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Zusammenfassung Das thermische Verhalten der Doppelsulfate vom Typus M₂M(SO₄)₂ · 6 H₂O wurde untersucht. In dieser Formel steht M für K oder NH₄, M für Ni, Co, Mg, Zn oder Fe.

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En l'honneur du Prof.A. A. Benedetti-Pichler, respectueusement.     

Décontamination chimique. Destruction rapide,douce, totale de toxiques organophosphorés et organosoufrés par une nouvelle série de ω-phtalimidoperacides

The chemical decontamination of toxic organophosphorus (pesticides or warfare agents) and sulfur compounds is of increasing importance. These products are destroyed by nucleophilic substitution for organophosphorus and oxidation of sulfur compounds. Peroxyacids, in micellar medium, are interesting for their reactivity on both families. We show here the interest of a new family: the phtalimidoperoxyacids.     

Propriétés magnétiques de phosphates et silicophosphates de titane

The magnetic properties of titanium phosphates ATiP₂O₇ (A=Na,K,Rb), A₂Ti₂(PO₄)₃ (A=K,Rb), BaTi₂(PO₄)₃ M g₃Ti₄P₆O₂₄ and titanium silicophosphates ATi₃P₆Si₂O₂₅ (A=K,Cs) have been investigated by magnetic susceptibility and electron spin resonance measurements. All the compounds are paramagnetic and the thermal variation of the susceptibility can be described with a Curie-Weiss law χ_m=χ₀+ C_m/T−θ_p. The values of μ_eff per Ti⁺³ and the spectroscopic data obtained from the 77K E.P.R. spectra are discussed as a function of the structural data.     

Synthèse de composés macrocycliques comportant deux fragments coordinants séparés et différents,de type bipyrldyl-2,2' et diphényl-2,9 phénanthroline-1,10.

Macrocyclic compounds containing a 2,9-diphenyl -1,10-phenanthroline subunit and a peripheral 2,2'-bipyridine chelate have been synthesized. In compound 4, the links between both coordinating fragments are flexible enough to allow complete folding of the molecule during complexation whereas in 5, the complexing moieties are rigidly held apart and cannot bind to the same metallic center.     

Extraction et dosage de traces de rhénium,en particulier dans les molybdénites

A simple solution to the difficult problem of the separation and determination of traces of rhenium contained in molybdenites is suggested. After the preliminary attack of the cres, rhenium is extracted quantitatively between, pH 8 and pH 9 by chloroform in the form of tetraphenylarsonium perrhenate. In this pH region the molybdenum remains in the aqueous phase.Calculation has allowed the determination of favourable conditions for the extraction of perrhenates by tetraphenylarsonium chloride and chloroform. Practical results are in satisfactory agreement with theory.The extracted rhenium, after conversion to the ions ReO₄^- in acid solution, is determined colorimetrically by reaction with thiocyanate and stannous chloride.By applying the method described it is possible to isolate and determine rhenium in molybdenites when the weight ratio rhenium/ore ecxeeds 10^-7.     

Etude structurale de bisalcoxy et de dialcoxyetains dérivés de l'éthyléneglycol et du pyridinediméthanol-2,6. mise en évidence d'une forme stannatrane pour un stannadioxocanne pyridinique

¹¹⁹Sn NMR is a good medium for determining the coordination number of tin atoms and association phenomena involved. By this technique the structures of three monomeric linear bis-alkoxy-tin(IV) (R₃SnOAOSnR₃) derivatives of ethylenerglycol and pyridine-2,6-dimethanol have been determined (R = n-Bu, Ph). In the case of cyclic dialkoxytins the ethyleneglycol derivative shows a variable temperature Sn^v dimeric → Sn^IV monomeric equilibrium (ΔH 64 kJ mol⁻¹), while the pyridinylstannadioxocane contains a Sn^v stannatrane, as determined by its ¹H, ¹³C and ¹¹⁹Sn NMR and mass spectra, and by cryogenic measurements. The pyridinyl-stannadioxocane is the only known stannatrane containing a pyridinic nitrogen atom.     

Etude structurale par RMN 29Si—V. Dérivés de la quinoléine et de l'isoquinoléine

A series of silylated compounds obtained from quinoline or isoquinoline were studied by ²⁹Si NMR using the selective polarization transfer (SPT). Both silicon chemical shifts and ²⁹Si, ¹H coupling constants have been measured. These results are the first example of coupling through siliconnitrogen bonds.     

Etude,par thermogravimétrie et spectrographie d'absorption infrarouge,de quelques sulfates doubles de la série magnésienne

Résumé Les spectres d'absorption infrarouge de sulfates doubles hexahydratés de la série magnésienne permettent de confirmer l'existence de fortes liaisons hydrogéne entre les molécules d'eau et le reste de la molécule.

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Summary The infrared absorption spectra of the hexahydrates of the double sulfates of the magnesium series provided evidence confirming the existence of strong hydrogen bonds between the water molecules and the rest of the molecule.

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Zusammenfassung Die IR-Absorptionsspektren der Doppelsulfathexahydrate des Nickels, Kobalts, Magnesiums, Zinks und Eisens bestätigen die Existenz starker Wasserstoffbindungen zwischen den Wassermolekülen und dem übrigen Anteil des Moleküls.

     

Étude Théorique de la Conductivité, Photoconductivité et de l'absorption Photoinduite de BaTiO3:Fe et KNbO3:Fe

Calculation of dark conductivity, and study of photoconductivity and light-induced absorption in BaTiO₃ :Fe and KNbO₃:Fe are performed at many light intensities. The results are interpreted in a two impurity level band model. This model allows to calculate the dark conductivity, to explain the behavior of the photoconductivity with the respect to the light intensities, and to study the light-induced absorption coefficient.