bluuebunny/crossref_metadata_2025_split huggingface dataset:
Étude De L'isomérie Géométrique Dans Les Cis‐et Trans‐1,2‐Dialcoylcyclopentanes Par Spectrométrie D'absorption Dans L'infrarouge
Authors: Natalis P. 
Published: September 2010

AbstractThe infrared spectra of cis and trans 1,2‐dimethyl‐, 1,2‐diethyl‐, 1,2‐methylethyl‐and 1,2‐methylpropylcyclopentane isomers have been recorded in the frequency range from 400 to 3000 cm–1. Assignments of some fundamentals are possible in a few cases when comparison of the spectra with those of cycloalkanes and other paraffinic hydrocarbons is straightforward. Cis and trans isomers are distinguishable by specific low frequency bands and corresponding combination bands. Other important differences between the infrared spectra of these isomers have been pointed out, mainly vibrations of methyl groups.
Contribution a L'Étude de la Clathration: Synthése et Propriétés des α‐Arylalcoylamines I
Authors: De Roocker A. , De Radzitzky P. , Labofina S. A. 
Published: September 2010

AbstractThe Leuckart reaction has been applied to the synthesis of 59 α‐arylalkylamines 38 of which are new compounds. Physical properties of those amines are tabulated and their pKa is shown to be related to their structure and to the polarity of their substituants. All those amines are of great value for the preparation of clathrating Werner complexes.
The Synthesis of Biologically Important Organic Compounds from Abiologic Systems
Authors: Berger Rainer 
Published: September 2010

AbstractL'étude présentée est une discussion sur la synthèse d'importants composés organiques dérivés de systèmes abiologiques. De nouvelles méthodes de synthèse de composés de ce genre ont été récemment rapportées. Dans le cadre de l'étude du problème de l'origine de la vie, ces méthodes nouvelles ont été appliquées dans une grande variété de conditions dont certaines existent dans l'univers et dont d'autres peuvent s'être réalisées sur la terre à son origine. Cette étude est une présentation abrégée de la synthèse de purines, pyrimidines, monosaccharides, nucléosides, nucléotides, acides aminés, polypeptides, etc.….
Étude du Comportement D'isoméres Géométriques Sous L'impact Électronique I. Les cis et Trans Décalines
Authors: Natalis P. 
Published: September 2010

AbstractMass spectrometric investigation of cis and trans decalines shows an influence of geometrical isomerism on the behavior of these two compounds under electron bombardment. Qualitatively mass spectra are identical, but quantitatively differences appear between relative abundances of molecular ions and most important fragment ions as well as between appearance potentials determined for the two fragment ions first produced.Greater stability of ionized trans decaline parallels its greater thermodynamic stability with respect to the cis isomer. Ionization potential has been measured for both isomers and found to be the same, 9.61 ±.02 ev, within experimental uncertainties, which means that an effect due to geometrical isomerism appears in both compounds in the ionized state. As shown by ionization potential and appearance potential data, lower energy is required to dissociate ionized cis decaline into fragments. This has to be related to the energy provided by steric conformation which is released in cis isomer when fragmentation occurs.In mass spectra of decalines and several other pairs of stereoisomers containing a cyclohexane ring it is possible to distinguish H atoms according to their axial or equatorial position.
Étude Infra‐Rouge Des Substances Possédant Une Liaison C=Se Adàjacente à un ou Plusieurs Atomes D'azote II. Sélénosemicarbazides
Authors: Collard‐Charon C. , Renson M. 
Published: September 2010

AbstractNous étudions les spectres infra‐rouges des sélénosemicarbazides progressivement substituées, dont la synthèse a été donnée dans un article précédent. Nous y fixons la bande CSe à 990–1070 cm−1, et nous discutons les attributions pour les autres bandes principales.
Chromatographie sur couche mince des despsides et des depsidones
Authors: Ramaut J. L. 
Published: September 2010

AbstractAfter separating and identifying β‐orcinol depsidones by thin layer chromatography, a technique permitting the chromatographic study of depsides and depsidones derived from orcinol is presented.Using Stahl's Kieselgel HF. 254 and Pastuska's phase, a good separation of both depsides and depsidones mixtures is obtained.This technique should be very valuable for the chemist interested in the lichenic acids as well as for the chimiotaxonomist using them for taxonomic purposes.
Potential constants and thermodynamic functions of the tetrachlorides of titanium and vanadium
Authors: Nagarajan G. 
Published: September 2010

AbstractUsing the observed Raman and infrared absorption fundamental frequencies of gaseous and liquid tetrachlorides of titanium and vanadium, the potential constants on the basis of Wilson's group theoretical method and the molar thermodynamic functions on the basis of a rigid rotator, harmonic oscillator approximation have been calculated.
Preparaton of 6‐oxo‐and 6‐thioxo‐5, 6‐dihydrobenzimidazo [1,2‐c] quinazolines
Authors: Poot A. L. L. , Willems J. F. , Heugebaert F. C. 
Published: September 2010

AbstractSubstituted 6‐oxo‐and 6‐thioxo‐5, 6‐dihydrobenzimidazo [1,2‐c] quinazo‐lines were prepared by cyclization of 5(6) and 4(7) substituted 2‐(o‐aminophenyl) benzimidazoles with chloroethyl formate respectively with carbon disulphide.The 5(6) and 4(7) substituted 2‐(o‐aminophenyl) benzimidazoles were prepared by reductive cyclization of the 4′ and 6′ substituted 2, 2′‐dinitroben‐zanilides which in their turn were obtained from o‐nitrobenzoyl chloride and 4 or 6 substituted o‐nitroanilines.
Étude du Comportement D'Isomères Géométriques Sous L'impact Électronique III. Corrélations Entre Les Spectres de Masse et la Structure Moléculaire Dans Une Série de 1,2‐DIALCOYLCYCLOHEXANES.
Authors: Natalis P. 
Published: September 2010

AbstractCorrelations between mass spectra and molecular structure are attempted in a series of cis and trans 1,2‐dialkylcyclohexanes previously investigated. Rather large differences appear between abundances of main fragment ions, especially (P‐R1)+ (parent ion having lost the R1 group) and (P‐R1‐H)+, some of which can be related to the different stability of the two kinds of stereoisomers. Metastable transitions indicate that an important fragmentation process is given by a sequence of the type P+→	(P‐R1)+→	(P‐R1‐R2)+.
Mécanisme D'Apparition D'Un Domaine Fermé de Démixion Dans Un mélange Binaire
Authors: Bellemans A. 
Published: September 2010

AbstractLe diagramme de phase d'une solution binaire associée: A+B+AB, est discuté en détail. On montre que, pour un choix particulier des paramètres d'interactions moléculaires, ce système présente un domaine fermé de démixion, symétrique par rapport au titre 0.5.
The Effect of Dissolved Electrolytes on the High Frequency Raman Band of Water
Authors: Lauwers H. A. , Van Kelen G. P. Der 
Published: September 2010

AbstractLes spectres Raman des solutions des halogénures des métaux alcalins dans l'eau ont été étudiés à diverses concentrations. L'intensité de la bande Raman dans la région de la vibration de valence OH est augmentée par la dissolution d'électrolytes dans l'ordre F−Cl−Br−I−. L'ion fluorure exerce une influence négative, opposée à celui des autres.L'analyse des spectres de mélanges binaires à concentration d'halogénure constante, nous a montré que l'effect de l'ion positif se manifeste dans l'ordre K+Na+Li+.En général on admet que la bande de vibration de valence OH peut être résolue en trois bandes de Gauss. De plus on attribue en grande partie la variation de l'intensité totale à une interaction de Fermi entre 2v2 et v1. La critique de ces deux hypothèses est faite À la lumière des données nouvelles.
Mean Amplitudes of Vibration and Thermodynamic Functions of the Dioxides of Chlorine, Sulphur and Selenium
Authors: Nagarajan G. 
Published: September 2010

AbstractAn elaborate discussion of the various methods regarding the molecular structure and vibrational spectral studies of the dioxides of chlorine, sulphur and selenium has been reported. The computed numerical values of (1) meansquare amplitude quantities, (2) generalized mean‐square amplitudes (meansquare parallel amplitudes, mean‐square perpendicular amplitudes and mean cross products) and (3) mean amplitudes of vibration for the temperatures at T=0 and T=298°K have been given for these molecules. Using the fundamental frequencies as well as normal frequencies the molar thermodynamic functions have been calculated on the basis of a rigid rotator, harmonic oscillator approximation for the temperature range from 100° to 1700°K.
Mean Amplitudes of Vibration of Some Octahedral XY6 Type Molecules
Authors: Nagarajan G. 
Published: September 2010

AbstractA brief survey on the vibrational analyses of the octahedral XY6 type molecules belonging to the symmetry point group Oh has been presented. For this type of molecules, the general theory of mean‐square amplitude matrices has been applied. The analytical expressions for the sixteen meansquare amplitude quantities as linear combinations of the symmetrized meansquare amplitude matrix elements have been obtained. The secular equations for the calculation of normal frequencies involving the symmetrized meansquare amplitude matrix elements have been given. For the twelve molecules namely, SF6, SeF6, TeF6, MoF6, WF6, UF6, NpF6, PuF6, ReF6, OsF6, IrF6 and PtF6, the computed values of (1) mean‐square amplitude quantities and (2) mean amplitudes of vibration at the temperatures T=0 and T=298°K.
La Substitution Nucleophile Activée en Série Aromatique. VI. Étude du Rapport Ortho‐Para. Réactivité Des 2 et 4‐Chloro‐Pyridines, Chloropyridinoxydes et Cloronitrobenzènes Avec la Pipéridine Dans la Méthanol.
Authors: Coppens G. , Declerck F. , Gillet C. , Nasielski J. 
Published: September 2010

AbstractThe 2‐ and 4‐chloro derivatives of pyridine, pyridine‐N oxyde and nitrobenzene have been reacted with molar piperidine in methanol. The results suggest an increased built‐in solvation in the case of 2‐chloropyridine‐N oxyde, and favour the electrostatic interpretation for this particular interaction.The “meta” substituted chlorides have almost identical reactivities; this points to the similarities of the inductive effects for the three activating groups.
Equilibre Acide‐Base de la N‐Diméthylamino‐4′, Diphényl, α‐Cyanazométhine et de Ses Dérivés de Substitution
Authors: Feytmans‐De Medicis Mme E. , Bruylants A. 
Published: September 2010

AbstractLes dérivés de substitution de la N‐diméthylamino‐4′, diphényl, α‐cyanazométhine (B): magnified image sont transformés en milieu acide en ions ammonium (anilinium) (BH+) correspondants dont la constante d'acidité (Ka) peut être déterminée par la méthode spectroscopique.La série étudiée comporte huit termes, caractérisés par les substituants (X‐) respectifs: NO2‐4, CN‐4, CN‐3, Cl‐3, Br‐4, Cl‐4, F‐4, CH3‐4; leurs constantes d'acidité sont liées entre elles par corrélation log Ka/KaO=ρσ, oú ρ=0,549. La valeur relative au terme non substitué a été déterminée par interpolation (KaO=0,26. 10−2). En outre, l'effet polaire (σ) du groupe α'‐phényl, α‐cyanazométhinique a été calculé (σ=0,351).
The Ionization Constant of α‐Hydroxy‐Isobutyric Acid
Authors: Deelstra H. , Verbeek F. 
Published: September 2010

AbstractThe apparent ionization constants of α‐hydroxy‐isobutyric acid were determined with and without added sodium perchlorate. The data were extrapolated to zero ionic strength to give the corresponding thermodynamic constant, pKT=4.00 (25°C).
Séparation de Flavonoïdes Par Chromatographie Sur Échangeur D'Ions du Type Carboxylique
Authors: Vancraenenbroeck R. , Rogirst A. , Lemaître H. , Lontie R. 
Published: September 2010

AbstractLa séparation chromatographique de flavonoïdes sur colonne d'Amberlite CG‐50 T1 ou T2 a été mise au point. La (+)‐catéchine et la (‐)‐épicatéchine, de même que plusieurs flavonols peuvent ainsi être séparés quantitativement par élution au moyen d'isopropanol en concentration croissante.
Propriétés physico‐chimiques de composés à caractère aromatique VI. Association par lien H entre le méthanol et quelques bases monoazaaromatiques dans le Tétra chlorure de carbone (1)
Authors: Coppens G. , Nasielski J. , Sprecher N. 
Published: September 2010

AbstractThe equilibrium constant for the hydrogen‐bond association aromatic base + methanol ⇋ complex in carbon tetrachloride has been determined by I.R. spectroscopy. The compounds examined are (K in 1.mole−1): pyridine (3,1), quinoline (3,5), isoquinoline (3,8), 1‐azaphenanthrene (4,7), 2‐azaphenanthrene (3,9), 4‐azaphenanthrene (1,6), 9‐azaphenanthrene (4,7), 9‐azaanthracene [acridine] (4,9), 1‐azafluoranthene (3,3) and 7‐azafluoranthene (4,5). The low value found for 4‐azaphenanthrene is attributed to steric hindrance. The other values are much too close together to allow any interpretation on the basis of electronic charges calculated by LCAO.
Mean Amplitudes of Vibration of Some Tetrahedral XY4 Type Molecules‐Part IV
Authors: Nagarajan G. 
Published: September 2010

AbstractThe computed numerical values of (1) mean‐square amplitude quantities, (2) generalized mean‐square amplitudes (mean‐square parallel amplitudes, mean‐square perpendicular amplitudes and mean cross products) and (3) mean amplitudes of vibration at the temperatures T=0 and T=298°K have been reported for the molecules PbF4, PbCl4, ZrCl4, HfCl4 and GeBr4 respectively. Besides these, the potential constants on the basis of Wilson's group theoretical method have been evaluated for the GeBr4 molecule.
Effet de la Longueur de la Chaîne Aliphatique Sur L'Association Des Alcools
Authors: Huyskens P. , Gillerot G. , Zeegers‐Huyskens T. H. 
Published: September 2010

AbstractThe curves of the dipole moments μ of the primary aliphatic alcohols in function of the concentration in CCl4 present a minimum that increases with the length of the hydrocarbon chain, as showed by R. Mecke. We have determined these μ values for several primary alcohols from methanol to octanol at 25, 35, 45, and 55°C. Assuming that the minimum is due to the presence of cyclic hydroxylic chains. it is possible to calculate from the curves the ratio r of alcohols molecules implicated in cyclic structures. The variation of r with the concentration C seems more similar to these of C1/2/C, where C1 is the monomer concentration, than to these of C3/1/C, C4/1/C, etc. One concludes to a predominance of trimeric cycles in the cyclic species, although it seems that the importance of higher cycles increases with the molecular weight in the alcohol. The theory of Mecke and Kempter, with the correction for the dimerisation constant, introduced by Coggeshall and Saier, is only applicable on the open species. The length of the aliphatic chain of the alcohol seems to have a rather moderate effect on the dimerisation and polymerisation constants of the open species. This factor has a greater influence on the closing of the open hydroxylic polymers, the cyclisation being more important when the molecular weight of the alcohol increases.
On the Metal Catalyzed Deposition of Carbon from Carbon Monoxide
Authors: Henry J. F. 
Published: September 2010

AbstractA set of equations describing the process of carbon deposition from carbon monoxide on a metal catalyst is proposed. Solutions valid for high and low concentrations of CO are obtained and compared to experimental results. In the high concentration limit, the calculated cumulative curve for the amount of carbon deposited is in good agreement with the experimental data, whereas in the low concentration case the agreement is very good.
2,2‐Bis(Aminométhyl)Propane‐1, 3‐Disulfonic Acid Disultam and its N,N′‐Diphénylderivative
Authors: Goethals E. 
Published: September 2010

AbstractThe synthesis and properties of 2,2‐bis (aminomethyl) propane‐1,3‐disulfonic acid disultam are described. It is a new pentaerythritol derivative and can be isolated in two isomeric forms which are probably the tautomers of the N‐S‐O triad system.
Studies on the Grignard Reaction‐VI. Steric Effects in the Grignard Addition Reaction on Ketones
Authors: van Schoote J. , Anteunis M. 
Published: September 2010

AbstractThe reactivity in the normal Grignard addition reaction is greatly reduced when the ketone is branched in the α‐position. Alkylation in β‐position has only slight effect and in the γ‐position there is no effect at all.
Studies on the Grignard Reaction‐VII (1) on the Mechanism of the Grignard Reagent Formation and the Wurtz Side Reaction in Ether
Authors: Anteunis M. , van Schoote (2) J. 
Published: September 2010

AbstractIn contradiction with accepted views about Wurtz coupling reactions during the preparation of Grignard solutions, the highly accurate Volhard titrimetric and the complexometric method show no difference. Checking the amount of coupling product by direct GLC the obtained results are discussed on the basis of a new mechanistic scheme, which assumes the formation of univalent magnesium radicals. These either disproportionate after preparation, or stay bonded as subhalide.
N.M.R. Experiments on Ketals Part I. Reaction Heat and Entropy of the Methyl Ketal Formation of Cyclohexanone, Cyclopentanone and Cyclobutanone
Authors: Anteunis M. , Alderweireldt F. , Acke M. 
Published: September 2010

AbstractThe methyl ketal formation is strongly exothermic (‐14,6 Kcal/mole) with cyclohexanone and moderately so with cyclopentanone (‐3,5 Kcal/mole) and with cyclobutanone (‐2,5 Kcal/mole). An exceptional low reaction entropy is noted for cyclohexanone (‐59 E.U.) and this is partly ascribed to the occurence of a high proportion of the twist conformation in cyclohexanone.
Physical Properties and Chemical Reactivity of Alternant Hydrocarbons and Related Compounds VII. The polarographic reduction of pyridine‐like heterocycles
Authors: Párkányi C. , Zahradník R. 
Published: September 2010

AbstractThe polarographic reduction of pyridine‐like heterocycles in 5.10−2 M tetraethylammonium iodide in 95% dimethylformamide gives well pronounced two‐electron waves. Half‐wave potentials of seven heterocyclic compounds have been determined in this medium. The data have been found to fit the correlation with energies of the lowest free π‐molecular orbitals in the HMO approximation. A similar correlation has also been obtained for half‐wave potentials of some heterocycles taken from the literature.
Halogen Substituted 1,3‐Cyclohexanediones II. New Chlorinated Cycloalkanones from 2, 2‐Dichlorodimedone
Authors: Schamp N. , Verzele M. 
Published: September 2010

AbstractA number of new substances obtained from 2,2‐dichlorodimedone are described. The most interesting features of the reactions are: a) the ring contraction to a 2‐cyclopentenone derivative with simultaneous carbon monoxide elimination, b) the isomerization procedure of halogenated ketones in dimethylformamide and hydrogen chloride, c)the aromatization to some new resorcinol derivatives. The high yields give most of the procedures a distinct preparative interest.
Mathematical Techniques in the Study of Coriolis Coupling in Tetrahedral XY4 Molecules
Authors: Cyvin S. J. , Brunvoll J. , Cyvin B. N. 
Published: September 2010

AbstractRelations between Coriolis coupling coefficients in tetrahedral XY4 molecules are evaluated, using the method of Cα and related matrices. It appears that the Coriolis coupling may be studied in terms of two independent Coriolis coefficients, e.g. ζ24 and ζ44. For these two quantities explicit equations are deduced, containing atomic masses, vibrational frequencies (in terms of λ values), and force constants of the molecule.
Étude Théorique des Molécules Conjugées I. Description d'une méthode SCF‐LCAO semi‐empirique
Authors: Leroy G. 
Published: September 2010

AbstractLa méthode de Roothaan n'est pas rigoureusement applicable à l'étude des molécules polyatomiques conjuguées. Pour tourner cette difficulté, on propose un procédé semi‐empirique basé sur les approximations de Pariser‐Parr‐Pople.On y tient compte d'une correction d'effet de charge et certaines intégrales sont évaluées à partir de données de spectroscopie atomique.La méthode ainsi obtenue permet d'étudier les molécules polyatomiques conjuguées contenant les atomes C,N,O ou S.
Contribution A L'Étude de La Clathration Synthèse et Propriétés des α‐Arylalcoylamines. II
Authors: De Roocker A. , De Radzitzky P. 
Published: September 2010

AbstractThe Leuckart reaction has been applied to the synthesis of 22 α‐arylalkylamines 16 of which are new compounds. An improvement of the Leuckart reaction is described. Physical properties of these amines are tabulated and their pKa have been measured when it was possible. All those amines are of great value for the preparation of clathrating Werner complexes.
Applications de la Spectrographie de Résonance Magnétique Nucléaire (R.M.N.) Dans le Domaine des Dérivés Polycycliques A Caractère Aromatique V. Dérivés Monosubstitués du Phénanthrène
Authors: Martin R. H. , Defay N. , Geerts‐Evrard F. , Figeys H. 
Published: September 2010

Abstract– N.M.R. spectra of aldehydes, methylketones and esters of phenanthrene, substituted in positions 2, 3 and 9, have been recorded at 60 Mc. In the nine cases examined in this work, it is possible to determine the position of substitution, without ambiguity.– Introduction of a methyl group in position 4 (angular position) has a deshielding effect on the proton located on carbon 5 (opposite angular position).– The main results are summarized in table I and figure 1.
Dosage Par Dilution Isotopique du Calcium et du magnésium A L'Échelle du Microgramme
Authors: Delwiche R. , Vosters M. 
Published: September 2010

AbstractThe quantitative analysis of Ca and Mg by isotopic dilution is described. The theory of isotopic dilution is recalled and a description of the apparatus used is given. The concentrations of standard solutions of Ca and Mg have been tested by this method. The results show that it is possible to measure quantities of these elements at the microgram level with an accuracy of 2 to 5% (2σ%). The main limitations of this method are due to contaminations during handling, and moreover, for Ca, to isotopic fractionation.
The Humulinic Acids II. Hydrogenation products. Chemical evidence for the structure of humulinic acids A and B
Authors: Lepoivre A. , Alderweireldt F. , Anteunis M. , Verzele M. 
Published: September 2010

AbstractChemical evidence shows that humulinic acids A and B (1) are cis‐trans isomers, corresponding to structure I and II or vice‐versa.
Synthèse de Thio‐ et Séléno‐Phtalides À Partir des Esters Imides Cycliques Correspondants ou de Leur Forme Tautomère
Authors: Renson M. , Collienne R. 
Published: September 2010

AbstractNous avons étudié l'équilibre tautomère et la possibilité de cyclisation de l'alcool o‐cyanobenzylique et de ses homologues sulfuré et sélénié. L'existence d'une forme cyclique à fonction iminoester, iminothioester et iminosélénoester a été prouvée et nous a permis d'utiliser celles‐ci pour mettre au point une méthode nouvelle de préparation des thio‐1, thio‐2, séléno‐1, séléno‐2, dithio‐1,2 et séléno‐2 thio‐1 phtalides. Parmi celles‐ci, la séléno‐2 phtalide n'avait pas pu être obtenue jusqu'à présent par d'autres méthodes, tandis que la séléno‐2 thio‐1 phtalide est particulièrement importante car elle constitue le premier exemple d'un ester mixte de soufre et de sélénium connue dans la littérature.
Acylation des Amidoximes Synthèse Nouvelle D'Oxadiazoles 1, 2, 4
Authors: Eloy F. , Lenaers R. , Buyle R. 
Published: September 2010

AbstractThe question of the structure of the acylamidoximes is reviewed. It appears that the acylation of amidoximes invariably occurs on the oxygen atom forming O‐acyl derivatives unless the NOH group is substituted. Until now, N‐acylamidoximes have never been isolated, with the exception of the acylation products of formamidoxime. N‐acylamidoximes, however, are formed as unstable intermediates during some particular methods of synthesis of 1,2,4‐oxadiazoles. A new method of forming derivatives of this heterocycle is described.