Sur le calcul a priori des déplacements chimiques de 1H et de 19F

We propose a new method for calculating ¹H and ¹⁹F chemical shifts in saturated organic compounds. Results show that the shifts are a balance of several contributions and allow an evaluation of these effects: a diamagnetic contribution d(—?) proportional to the net charge ? of the electronic environment of the nucleus considered and paramagnetic contributions p_X of each of substituents, constant attached to the substituent X in any molecule. For both nuclei, d values were deduced from a theoretical calculation of the screen in the free atom. This method, using a restricted number of parameters obtained from experiment, lead to the observed chemical shifts with a mean accuracy of ± 0,32 ppm for ¹H and ± 11 ppm for ¹⁹F. Therefore this method gives a simple quantitative relation between chemical shift and structure from which precise indications about the origin of the contributions from neighbouring electronic surroundings can be obtained.     

Etude des systèmes binaires formées par le chlorure de cyanogène et par les tétrachlorures de carbone,de silicium,de germanium et d'étain

Study of binary systems formed by cyanogen chloride and the tetrachlorides of carbon, silicon, germanium and tin. The diagrams of binary mixtures of cyanogene chloride with the tetrachlorides of carbon, silicon, germanium and tin were studied. Only SnCl₄ gives an addition compound: SnCl₄ · 2ClCN. The existence of the complex was confirmed by X-ray diffraction and vapour pressure measurements. This complex gives SnCl₄ · 2NOCl on treatment with nitrosyl chloride.     

Sur les spectres d'absorption infrarouge,entre 2,5 et 16 μ, de semicarbazones

The spectra of 120 semicarbazones in the solide state have been studied between 2.5 and 16 microns in order to correlate absorptions and structures. We have considered most particularly the absorptions v(N-H) and the so-called amid-I and amid-II bands.     

Sur les conditions de formation des complexes des chloroalkylgallium (ClnR3−nGa) avec diverses bases de Lewis (R2O,R2S,R3N et R3P): étude par spectroscopie de RMN (1H)

From an NMR (¹H) study of various systems chloroalkylgallium/Lewis bases, it appears that the four types of gallium compounds (Cl_nR_3?nGa) form adducts with trialkylamines, trialkylphosphines, ethers and sulphides, and that in all cases the 1:1 complex seems to be the only existing one. Its stability mainly depends on the number of chlorine atoms bound to the gallium and on the nature of the donor site.     

Reductions par le zinc en presence d'acides—II : Formation de cyclopropanes lors de la reduction des aldehydes aromatiques par le zinc en presence de trifluorure de bore et d'olefines

The reduction of several p-substituted aromatic aldehydes by zinc in the presence of boron trifluoride and cyclic or open chain olefins, vinyl or allyl ethers or acetates, leads to the corresponding substituted arylcyclopropanes by way of carbene intermediates.     

Etude de la réactivité de la fonction carbonyle avec le cétène en présence d'un alcoxyde de titane. 2e communication. A propos de l'interprétation de quelques spectres RMN de β-hydroxyesters formés

The NMR. spectra of a serie of β-hydroxyesters have been studied. It has been found that the methylene protons are magnetically nonequivalent only when the substituents on the center of asymmetry of I or II are very different. The magnetically non-equivalence of the isopropylmethylprotons arise when the β-hydroxyesters contain an aromatic or aromatic conjugated group directly bonded to the asymmetric carbon. The interpretation of this finding is proposed.     

Etude par RMN 1H des effets de solvant sur les déplacements chimiques et les couplages vincinaux des benzothiénopyridines

The solvent/solute interactions of four isomeric benzothienopyridines (parent compounds) have been investigated by ¹H n.m.r. A close study of the second-order spectra shows: (i) a preferential orientation of the solvent molecules (acetone) surrounding the pyridine ring; (ii) large variations in the coupling constants of the benzenic part of the benzothienopyridines as a function of the solvent; (iii) a preferential interaction of the pyridine ring in collision complexes with benzene. These results can be applied to a comparative study of the complexes between DNA base pairs and intercalating derivatives.     

Synthese de ligands de type amino-diphosphinites; etude en RMN 13C et 31P. Application a la dimerisation du butadiene par les complexes du nickel

The new chiral aminodiphosphinite ligands are readily prepared from chiral amino acids. These compounds were characterized by ¹³C and ³¹P NMR spectroscopy and their behaviour as homogeneous catalysts was investigated in the linear dimerization of butadiene.     

Etude des formes fermées et ouvertes de spiropyrannes benzothiazoliniques en RMN 13C et 1H par transformée de Fourier

Benzothiazolinic spiropyrans, merocyanines and photomerocyanines, thermally stabilised to a high degree, have been studied by means of Fourier transform ¹H and ¹³C NMR. The results show the polarity of open forms such as merocyanines and photomerocyanines, their trans configuration, the alternation of the electronic density on the dimethine bridge between the ‘benzothiazolinic’ and ‘phenolate’ part of these molecules, and also a favoured configuration when photomerocyanines have an alkoxy or aryloxy group on the 3 position.     

Sur la Similitude des Déformations du Noyau Cyclohexanonique Induites par les Groupes Tertiobutyle et gem-Diméthyle

X-ray and NMR (250 MHz) data for chlorinated 4,4-dimethylcyclohexanones lead to the following conclusions: carbonyl and chlorine substituent effects on ²J and ³J coupling constants are similar to those observed for 4-tert-butylcyclohexanones. In other respects, the gem dimethyl and the tert-butyl groups induce on the ring similar large ⁴J coupling constants (H-3′? C-3? C-4? C-5? H-5′); the results can be interpreted in terms of local gemoetric deformations and additivity of these deformations. The determination of dihedral angles by Lambert's method and from X-ray data shows the identity of the structures in the solid state and the dissolved state and confirms the great structural similarity between 4-tert-butyl- and 4,4-dimethylcyclohexanone derivatives.     

Addition de l'Hexafluoroacétone sur les Acides Carboxyliques—Mise en Évidence par RMN 1H et 19F. Application à l'Analyse d'un Mélange d'Acides

The compound HO? C(CF₃)₂? O₂CR results from nucleophilic addition of a carboxylic acid to the carbonyl group of hexafluoroacetone. I.r. and n.m.r. (¹H, ¹⁹F) spectroscopy have been used to show that the addition is reversible. The addition is favoured by a lowering of the temperature and by the use of acids in which the group R is electron donating. Moreover, the chemical shift of the CF₃ groups (or of the OH group) in the addition product is dependent on the nature of R. Thus, this reversible addition can be used as a method for the analysis of a mixture of carboxylic acids by n.m.r. spectroscopy.     

Détermination du champ de force de valence et des modes normaux de vibration des composés d'addition de l'acétone avec le trifluorure de bore

A valence force field for coordination compounds between acetone and boron trifluoride is computed: it is based upon vibrational spectra of six isotopic species and compared with the force field of free acetone and BF^?₄ ion. The formation of complex modifies the electronic state of the base and consequently the diagonal force constant of the CCO group and of the CH bonds. The force constant of the coordination bond (OB) is estimated as 2.10 mdyne Å^?1. Below 800 cm^?1 all modes involve motions of the acid and base; none corresponds to a stretching of the coordination bond.     

Etude de composés d'addition des acides de Lewis XXVIII. Constantes de Hammett et vibration carbonyle des composés formés par TiCl4 et SbCl5 avec des chlorures de benzoyle parasubstitués

The adducts of benzoyl chlorides p-substituted by CH₃O? , CH₃? , and H? with the electronic acceptors SbCl₅ and TiCl₄ have been prepared, and the IR. absorption spectra of the solid products studied.     

Spectres RMN des Polysaccharides et de leurs Dérivés: Influence des Substituants sur le Déplacement Chimique 13C

Methyl and acetyl substituent effects on ¹³C chemical shift have been determined on (α 1→3), (α 1→4), (β 1→3) and (β 1→4) linked polysaccharides such as pseudo-nigerane, β-cyclodextrine, amylose, laminarane and cellulose. Methyl α- and β-D -glucopyranoside have been used as monomer model compounds. Shift determination of hydroxylated and substituted polysaccharides requires unambiguous assignment of their ¹³C spectra. Selective heteronuclear spin decoupling and the isotope effect of deuterated hydroxyl have been used as assignment techniques.     

Recherches sur la formation et la transformation des esters LXXXI [1]. Sur la réaction d'isothiocyanates avec l'acide hydrazinoéthylphosphorique,et de l'isocyanate de phényle avec l'acide colaminephosphoreux

Hydrazinoethyl phosphoric monoester has been prepared by reacting hydrazinoethanol with polyphosphoric acid, and isolated as di-sodium salt. Sodium hydrazinoethyl phosphate reacts with phenylisothiocyanate (in H₂O+ethanol) to yield mainly the derivative thiocarbamoylated at the substituted nitrogen atom. This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 3-amino-2-phenylimino-thiazolidine in 62% yield. Sodium hydrazinoethyl phosphate reacts with o-methoxycarbonylphenyl isothiocyanate (in H₂O+dioxane) at the unsubstituted nitrogen atom to yield mainly the corresponding quinazoline derivative (IV, X = OPO₃Na₂). This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 2-o-carboxyphenylamino-dihydro-δ²-1, 3, 4-thiadiazine (Va) in 55% yield (hydrolysis of the lactamic function as well). Aminoethyl phosphorous monoester (colaminephosphorous acid) reacted with phenylisocyanate (in H₂0+dioxane) in slightly alkaline medium (one equivalent of NaOH) yields sodium N-phenylcarbamoylaminoethyl phosphite. Refluxed for 20 minutes in 1N NaOH, this carbamoyl derivative is not cyclized but only hydrolyzed to the open-chained N-phenyl-N′-hydroxyethylurea (VII).     

Effets de substituant,d'hétéroatome et de solvant sur les cinétiques de décoloration thermique et les spectres d'absorption de photomérocyanines en série spiro[indoline-oxazine]

Substituent, Heteroatom, and Solvent Effects on the Thermal-Bleaching Kinetics and Absorption Spectra of Photomerocyanines Issued from Spiro[indoline-oxazines] Quantitative information useful for the development of new photochromic systems is obtained from the study of heteroatom and substituent effects on the thermal-bleaching kinetics and the absorption spectra of the photomerocyanines issued from spiro[indoline-oxazines]. The effect on photochromic properties of the presence of N-atoms either in the dimethine bridge or in the aromatic rings has been investigated through the comparison of spiro[indoline-naphthopyrans] C with spiro[indoline-naphthoxazines] A and with spiro[indoline-quinolinoxazines] B . Besides the occurrence of biexponential thermal-bleaching kinetics in non-polar solvents is observed: a tentative explanation for this observation is given which involves the formation, in either sequential or parallel steps, of energetically distinct stereoisomers of the opened form.     

Détermination par RMN 1H et 13C de la Conformation Favorisée des Ozonides d'Acènes

The preferred conformation of 9,10-dimethylanthracene ozonide has been established by ¹³C and ¹H NMR. Results hold for other anthracenic ozonides such as those of 9,10-dimethoxyanthracene and anthracene. The latter compound, resulting from the ozonolysis of anthracene, has for the first time been shown to exist in solution.     

Etude par RMN. de polyaminocarboxylates de terres rares,II. Nitrilotriacétates de scandium,yttrium, lanthane et lutécium

Proton nuclear magnetic resonance has been used to study the chemistry of the diamagnetic nitrilotriacetate complexes of scandium, yttrium, lanthanum and lutecium in aqueous solution. Complexes with ligand-to-metal ratios of 1 and 2 are present depending of the solution conditions. The ligand exchanges by spontaneous and by acid catalysed dissociation of the metal-bis-nitrilotriacetate, and also by a bimolecular process involving the free ligand and the complex. The ligand exchange rate constants decrease with the ionic radii:lanthanum > yttrium > lutecium > scandium.     

Etude par RMN du Proton et du Carbone-13 de Pyrimidines Substituées. I—Effets de Substituant dans les Dérivés Méthylés et Aminés

Substituent effects of methyl and amino groups on the chemical shifts of pyrimidine have been investigated by ¹H and ¹³C n.m.r. and compared with similar data obtained for benzene and pyridine. Taking into account pairwise interactions, the chemical shifts calculated by using an additivity relationship are in very good agreement with the experimental results, except for some hindered pyrimidines. This study enabled us to assign the ¹³C n.m.r. spectra of some trisubstituted pyrimidines.     

Etude de substances modeles susceptibles de complexer les metaux de transition dans les fractions lourdes du petrole II. Caracterisation par ESCA et LAMMA,de complexes du vanadium avec des ligandes sulfures. Comparaison avec les asphaltenes

The complexes obtained by the action of vanadyl ethylate on some open-structured ligands (type 1,4,8,11-tetrathiaundecane TTU) are characterized by mass spectroscopy with laser impact (LAMMA) and by photoelectron spectroscopy ESCA. The results are compared with those obtained from some reference compounds and several fractions of asphaltenes.