Etude thermochimique de quelques benzoates de cuivre(II) solvates

Some compounds of copper(II) benzoate solvated by ligands containing either oxygen (water, alcohol, dioxan) or nitrogen (amines, amides) or both, have been prepared. The thermal decomposition has been studied by TG and ATD methods. The standard enthalpies of formation have been determined and verified by some estimation methods.     

Reactivite multiple des amines stannique: cas de certains derives carbonyles conjugues

en]Organotin amines react with α-enones to give various products depending on the nature of the initial carbonyl derivatives. 1,2 or 1,4-addition or, abstraction of an hydrogen from the α position were observed; each kinetic product being able to form a more stable species.     

Reactifs de grignard vinyliques γ fonctionnels : II. Iodolyse,alkylation et arylation des iodo-alcools

Iodination of γ-functionally substituted vinylic Grignard reagents, prepared by addition of organomagnesium compounds to α-aactylenic or α-allenic alcohols gives vinyl iodides stereospecifically. Treatment of these iodides with Grignard reagents in the presence of (PPh₃)₂NiCl₂ gives allylic alcohols. This reaction proceeds with high stereoselectivity.     

Alcoolyse et glycolyse de derives organozinciques et organocadmiens par des composes chiraux

The reaction between organozinc or organocadmium derivatives and different chiral hydroxy compounds leads to the corresponding alcoholates and glycolates which can be used as initiators in polymerizations.The composition of such initiators is defined by the ratio i_S = R-M-O/O-M-O of the number of alkylalkoxy groups to the number of dialkoxy groups. This ratio depends on the nature of the organometallic and hydroxy compound and on the conditions of reaction used to prepare them.Toward a given hydroxy compound, the reactivity of the organometallic derivatives follows the order: ZnEt₂ > CdEt₂ > CdMe₂.Primary alcohols and 1,2-diols are more reactive than secondary alcohols in the case of organozinc compounds, while in the case of organocadmium compounds the secondary alcohols are more reactive than primary alcohols, but less reactive than 1,2-diols. The kinetics of the reaction can be followed by monitoring the variation of optical activity of the solution.Several compounds having definite stoichiometry have been isolated and identified by their NMR spectra.     

Etude des aldimines lithiees : I. Synthese d'aldehydes ω-halogenes et de dialdehydes

Aldimines are conveniently metallated, at a position α to the functional group, by using very powerful bases i.e. activated lithium dialkylamides generated in situ from lithium and a secondary amine in benzene/hexamethylphosphoric triamide. The anions obtained are alkylated with various ω,ω′-dihalogenoalkanes to give, after aqueous acid hydrolysis, good yields of ω-halogenated aldehydes and dialdehydes.     

Polymerisation et copolymerisation anioniques du methyl-2 ethyl-2 thiiranne

The anionic polymerization of a novel episulphide (2-methyl-2-ethyl thiirane) has given living polymers. Random and block copolymers could be prepared, and measured and calculated molecular weights are in good agreement. Homopolymers prepared with anionic initiators are semi-crystalline (T_m ≈ 110°C) and soluble. Electron diffraction results suggest however that their crystalline order is imperfect.     

Etude thermoanalytique de substances psychotherapeutiques. I. Anxiolytiques. Phenprobamate,meprobamate, clobazam et medazepam

The thermoanalytical study of phenprobamate (a), meprobamate I (b), clobazam (c), medazepam I (d) has enabled the existence of polymorphs for (d) to be established, and to confirm that of (b). The thermal stability and decomposition kinetics of commercial forms of drugs have been determined; their temperatures and intervals of fusion are given. Knowing the thermal behaviour of these compounds, their degree of purity: 99.67±0.19% (a), 99.32± 0.04% (b), 99.61±0.07% (c), 99.66±0.14% (d); their enthalpy, 27.58±0.69 (a), 34.23±1.22 (b), 30.38±0.81 (c), 21.48±0.75 kJ mole^-1; and entropy of fusion have been evaluated by differential scanning calorimetry.     

Determination des structures du cyclooctadiene dichloro palladium et du cyclooctadiene-1,5 (phenyl sulfonyl methanato) chloro palladium

A crystalline derivative is formed when lithiated phenyl methyl sulfone is treated with CODPdCl₂. The X-ray structure determination is described. The anionic carbon is tetrahedral.     

Etudes cristallographique magnétique et par résonance Mössbauer de la variété de haute température du pyrophosphate NaFeP2O7

Single crystals of the high-temperature form of NaFeP₂O₇ have been grown by a flux technique. II-NaFeP₂O₇ crystallizes in the monoclinic $\text{P2}{}_1\text{c}$ space group with lattice parameters: a = 7.298(2) Å, b = 7.874(2) Å, c = 9.536(3) Å, β = 111.85(2)°. The structure refined from 1481 independent reflections leads to R = 0.044 and confirms the work previously published by M. Gabelica-Robert, M. Goreaud, P. Labbe, and B. Raveau (J. Solid State Chem.45, 389, 1982). Magnetic Mössbauer resonance studies have shown the existence of antiferromagnetic ordering with a weak ferromagnetic component below 30 K. The FeO bond is markedly ionic in character due to the highly polarizing power of phosphorus in tetrahedral site.     

Etude magnétothermoélectrique de la transition métal-semiconducteur dans les composés Cr2+ϵSe3 (0 ≤ ϵ ≤ 0,04): II. Etude expérimentale et interprétation: mécanismes de conduction

A negative and very large longitudinal Nernst effect is encountered in the semiconducting compounds of the Cr_2+?Se₃ family. The sign, the amplitude, and the variation of the longitudinal Nernst coefficient Q″(H) versus temperature could be explained either by phonon-drag phenomena or by the presence of magnetic polarons. For an n-type semiconductor, the Seebeck coefficient curve S₀ = f(T) exhibits a peak near the Néel temperature. The vanishing of this peak when a magnetic field is applied confirms the existence of magnetic polarons. Under an infinitely high field, the observed proportionality between the coefficient S(∞) and the temperature shows that the conduction is due to the hopping of polarons (Cutler and Mott criterion). To interpret the thermoelectric power and electrical conductivity a model is proposed in which electrons are localized by the disorder of vacancies (Anderson localization). Each carrier, surrounded by a ferromagnetic cluster and a lattice deformation, is moving by jumps. On another semiconductor compound a reversal of the sign of the longitudinal Nernst effect appears at 47 K, in addition to the change of sign of S₀ at 28 K. Such a behavior may be explained by the presence of two types of carriers at low temperatures.     

Reactions d''addition thiophile et carbophile de composes organometalliques sur le groupement thiocarbonyle de deux thiocetones non enethiolisables

2,2,4,4-Tetramethyl-3-pentanethione and adamantanethione react with Grignard reagents (RMgX) to give either thiophilic addition (with R = aliphatic group) or carbophilic addition (with R = unsaturated group). However, two exceptions have been observed.     

Organocuivreux vinyliques : II. Deuterolyse,iodolyse, couplage et alcoylation stereospecifiques des vinyl-cuivres

Vinylcopper derivatives, obtained by stereospecific addition of alkylcopper compounds to 1-alkynes, are transformed with retention to various ethylenic structures; 1-deutero-1-alkenes, symmetrical conjugated dienes, 1-iodo-1-alkenes, di- or tri-substituted alkenes and primary or secondary allylic alcohols.     

Synthese et reactivite d'un complexe diene-fertricarbonyle derive du phenyl-1-dimethyl-3,4-phosphole

The complex (DMPP)Fe₂(CO)₇ in which DMPP (1-phenyl-3,4-dimethylphosphole) is η⁴-coordinated with Fe(CO)₃ through its diene and η¹-coordinated with Fe(CO)₄ through its phosphorus atom is selectively decomplexed at phosphorus to give (DMPP)Fe(CO)₃ by reaction with AlCl₃ followed by NH₄OH. This new η⁴-complex (DMPP)Fe(CO)₃ can be oxidized, sulfurized and quaternized at phosphorus by H₂O₂, S₈, and PhCH₂Br and MeI, respectively, as an ordinary phosphine without decomplexation of the diene. As a free phosphole, this complex also gives a ring-expanded product by reaction with benzoyl chloride, water and Et₃N. In the presence of some metallic salts such as (PhCN)₂PdCl₂, it loses CO to give the bimetallic sandwich [(DMPP)Fe(CO)₂]₂. It can also give some new bimetallic complexes such as [(DMPP)Fe(CO)₃]W(CO)₅ by complexation of the phosphorus lone pair by W(CO)₅(THF).     

L'addition des organomagnesiens aliphatiques satures sur les triples liaisons disubstituees non conjuguees: IV. Influence d'un groupement fonctionnel thioether en α de la triple liaison. Action catalytique du cuivre

The addition reaction of ethylmagnesium bromide to the triple bond of the compounds of general formula EtSCH₂CCCH₂Y (where Y is the basic group OH, OR, NR₂, or SEt) is very weakly activated by the thioether group. Catalysis by magnesium impurities may be involved.With 1-ethylthio-4-dialkylamino-2-butynes (Y NR₂), (E) trisubstituted ethylenic compounds are selectively obtained. The reaction more readily occurs after the addition of cuprous chloride to the Grignard solution, and then its stereoselecitvity may be reversed.     

Cristallochimie de TlIII6TeVIO12 et TlI6TeVIO6E6: un exemple original de l'activite´ste´re´ochimique de la pairee´lectronique 6s2(E) du thallium(I)

Both crystal structures of Tl₆TeO₁₂ and Tl₆TeO₆E₆ compounds have been determined, the former by X-ray single crystal techniques, the latter by powder neutron diffraction techniques. They crystallize in the trigonal system, space groupR3¯ the corresponding hexagonal cell parameters area = 9.645(2) Å,c = 9.421(2) Å, anda = 9.5722(3) Å,c = 9.3494(4) Å, respectively, withZ = 3. In both compounds tellurium(VI) is octahedrally coordinated to oxygen atoms with TeO distances of 1.936Åfor the Tl(III)-containing compound, i.e., Tl₆TeO₁₂, and 1.946Åfor Tl₆TeO₆ (Tl(I)). Tl(III) is surrounded by seven oxygen atoms sitting at the summits of a distorted monocapped trigonal prism. Tl(I) is linked to three oxygen atoms, forming a distorted TlO₃ pyramid. The lone pairs brought by Tl(I) are in the positions precedingly occupied by oxygen atoms in the crystal structure of Tl₆TeO₁₂. This is an outstanding example of the crystallochemical role of the lone pairsE which act like oxygen atoms, making Tl^I₆Te^VIO₆E₆ isostructural with Tl^IIITe^VIO₁₂. Structural relationships with fluorite type network are discussed.     

Calcium alkoxyalanates : II. Advances in the synthesis

Simple syntheses of calcium alkoxyalanates starting from NaAlH₄, CaCl₂ and alcohols involving evolution of hydrogen and separation of sodium chloride are reported. More complex methods, which allow the preparation of calcium alkoxyllalanates without loss of hydride hydrogen from NaAlH₄, CaCl₂, NaOR and AlX₃ (X = OR, Cl) have also been developed.     

Complexes dinucleaires pontes des metaux d8: VII. Reactions d'addition oxydante d'halogenures d'alkyle et d'acycle aux complexes μ-halogenes du rhodium(i) [RhX(CO)(PR3)]2. Structure cristalline de [RhCl(CO)(PMe2Ph)(Me)(Br)]2

The halogen bridged binuclear complexes of rhodium(I) [RhCl(CO)(PR₃)]₂ undergo oxidative addition with methyl halides to yield the complexes [RhCl(CO)(PR₃)(Me)(X)]₂ (X = Cl, Br). The crystal and molecular structures of [RhCl(CO)(PMe₂Ph)(Me)(Br)]₂ have been determined from a single crystal by use of X-ray crystallographic methods. The space group is Pca2₁ or Pacm with a 19.501(5), b 10.381(4), c 13.641(5) e? Z = 4. Parameters of 30 nonhydrogen atoms in the space group Pca2₁ were refined by the full-matrix least squares technique to a conventional R factor of 0.073. In a binuclear unit, each rhodium atom is in an octahedral environment being bonded to a carbonyl group, a methyl group and a tertiary phosphine ligand and three halogen atoms for which, due to a disorder phenomenon, the diffusion factors have been determined as the average between those of chlorine and bromine atoms. In solution the cis-migration of the methyl groups occurs, leading to the acetyl complexes. In the case of CH₃I, it is shown that an equilibrium is present in solution: [RhCl(CO)(PR₃(Me)(I)]₂ ? [RhCl(COMe)(PR₃)(I)(solvant)]₂] Carbonylation reactions shift this equilibrium to give the complexes [RhCl(CO)(COMe)(PR₃(I)]₂. Such complexes are readily prepared by direct oxidative addition of acyl halides to the compounds [RhCl(CO)(PR₃)]₂.     

Non-stoichiometric molybdenum oxides as cathodes for lithium cells: Part II. Secondary batteries

Mo₄O₁₁, Mo₈O₂₃ and Mo₉O₂₆ have been examined as cathodes for secondary lithium cells. These oxides can form ternary phases from which Li⁺ can be almost quantitatively recovered on charge, for limited e/Mo values (e.g. 0.8 for Mo₈O₂₃). Higher values of e/Mo make the reduction process irreversible due to the destruction of the original lattices. Cyclic voltammetry experiments have shown that these oxides can maintain their reversible behaviour for many cycles, provided the cathodic scanning is limited. Cycling of prismatic Li/Mo₈O₂₃ cells has confirmed that this oxide can behave reversibly with good voltage retention even at discharge depths near the limiting value.     

π-Arene complexes of the main group elements. II. Complexes of cadmium(II) and zinc(II)

π-Arene complexes of cadmium(II) and zinc(II) have been prepared from the first time. The 1:1 complexes Cd(AsF₆)₂. Arene(Arene=hexaethylor hexamethylbenzene, pentamethylbenzene, durene, $\text{p}$-xylene or benzene), Cd(SbF₆)₂. Arene(Arene = hexamethylbenzene, toluene or benzene) and Zn(SbF₆)₂. Arene(Arene = hexamethylbenzene or pentamethylbenzene) are synthesized from the strong acid salt and arene in liquid sulfur dioxide. ¹H and ¹³C NMR spectra are consistent with localized bonding of the arene to the metal cation. Exchange-averaged vn]¹³C chemical shifts for the systems Cd(AsF₆)₂-arene-SO₂ confirm the 1:1 stoichiometry in solution and suggest that the stabilities of the complexes are in the approximate range 0.48 – 2.1 M^?1 for the series benzene-hexamethylbenzene. For the system Cd(AsF₆)₂-C₆Me₆-SO₂, a detailed ¹¹³Cd NMR study is consistent with the solution stoichiometry and stability determined from ¹³C NMR. In general, complexation to an arene produces deshielding of the ¹¹³Cd resonance of Cd(AsF₆)₂.     

Spectres de vibration de composes organiques des elements de la colonne IVB : V. Derives cycliques oxygenes du silicium et de l'etain: Oxa-1 sila-2 cyclopentanes,oxa-1 stanna-2 cyclopentanes et cyclopentenes

Infrared and Raman spectra of two 1-oxa-2-stannacyclopentanes, three 1-oxa-2-stannacyclopentenes and three 1-oxa-2-silacyclopentanes have been examined in the 3600—100 cm^?1 region. Assignments of the main bands observed are discussed.