bluuebunny/crossref_metadata_2025_split huggingface dataset:
The structure of molluscan haemocyanins and their homology with tyrosinases
Authors: Préaux Gisèle , Gielens Constant , Witters Raphaël , Lontie René 
Published: September 2010

AbstractHaemocyanins, proteins with binuclear copper sites, are dioxygen carriers in four classes of molluscs: gastropods, cephalopods, polyplacophorans (the chitons), and bivalves (in the latter class only in a limited number of primitive species). They show typical quaternary structures and dissociation patterns in the analytical ultracentrifuge and in the electron microscope.The subunit (Mr 450 000) of the βC‐haemocyanin of the gastropod Helix pomatia is composed of eight functional units, which have been separated by chromatography after limited proteolysis. The two types of subunits (Mr 450 000) of the αD‐ and αN‐Hc components are also constituted of eight functional units like the subunit (Mr 390 000) of the haemocyanin of the cephalopod Sepia. The subunit (Mr 350 000) of the haemocyanin of the cephalopod Octopus is composed of only seven functional units.The amino‐acid sequences of a functional unit of Helix and of Octopus haemocyanin show a homology with the CUB site of arthropodan haemocyanins near the ligands of copper, but not with their CUA site. There is a striking homology near the potential copper ligands for both the CUA, and the CUB sites of molluscan haemocyanins with those of tyrosinases from the bacterium Streptomyces to man.
Spin delocalisation in heterocyclic captodative radicals1,2
Authors: Nootens C. , Merényi R. , Janousek Z. , Viehe H. G. 
Published: September 2010

AbstractThe open chain and heterocyclic precursors of 12 captodative radicals 1–4 were prepared in order to perform their ESR spectroscopic evaluation. Each of them contains a ketone as a captor substituent and an amino, a thioether or an ether substituent as a dative group. Spectral comparison shows the influence of geometry since 5‐membered cd‐radicals with thio‐groups are more delocalised than their 6‐membered or open chain analogues. Interestingly, when cyclic conjugation becomes possible because of an additional double bond such as in 4b, no marked difference of spin delocalisation is observed in comparison with dihydroanalogue 2b. As the dative substituent changes from CH3N‐ to S‐ and to O‐ (in 2b‐2d) the delocalisation decreases and the participation of the corresponding carbonyl group increases.
Similarites De Comportement Et Formes Locales La Topologie Reflet De La Topographie
Authors: Dubois J. E. , Doucet J. P. , Panaye A. 
Published: September 2010

AbstractIn DARC PELCO topological correlations, each site contribution is individualized, and interaction terms are accurately identified, Topological filiations underlying such approaches very often reflect topographical filiations. We establish that a simplified conformational analysis justifies and assesses the predictive potency of this PELCO model by structural interpolation. Its interpretative ability is based on analysis of the more important site valuations and possibly on interaction terms. Identifying the favored conformers allows us to build actual topographical correlations on the same principle of site evaluation. For instance, gauche or anti carbons provide different contributions to 13C shifts or ΔH comb. values in the alcane series. Further interpretative refinements are available. For instance, in hydrophobicity of amines, alcohols and ethers, each site contribution is evaluated in terms of inductive effect, lone pair accessibility and ability to form hydrogen bonds.
Effet D'Un Champ Magnetique Sur L'Ecoulement Des Oxydes De L'Azote NO Et NO2 Dans Un Milieu Granuleux Effect of a magnetic field on the flow of nitrogen oxydes NO and NO2, through a granulous medium
Authors: Gire Alain , Lomaglio Madame Germaine , Theobald Jean Gérard 
Published: September 2010

AbstractWe show, using a molecular beam method, that the flow of the gas nitric oxyd can be affected by a magnetic field, in relation with the angular momentum of the molecule.
Hydrogenolysis of Ethane on RH Powder. Application of the Landing Site Model
Authors: Crucq A. , Degols L. , Frennet A. , Lienard G. 
Published: September 2010

AbstractThe kinetics of ethane hydrogenolysis catalysed by Rh powder is studied in a very wide range of experimental conditions: 10 torr < PH2 < 1400 torr; 147°C < T < 245°C; 10torr < PC2H6 < 500torr. The results are compared with previously published results obtained under transient conditions on the same metal at much lower temperature (0°C < T< 80°C) and pressure (P < 0,01 torr) that allowed to propose the reaction mechanism. With this mechanism, using the landing site model and published data on hydrogen adsorption, the kinetic parameters, orders and activation energy, are calculated and shown to be in good agreement with experimental values.
1,3‐Dimethylindole: NMR Spectroscopy and Reactivity Towards Ethyl Carbonate in the Presence of Buthyl Lithium
Authors: Avendaño Carmen , De Diego Carmen , Elguero José 
Published: September 2010

AbstractWe report the reactivity of the 2‐lithium derivative of 1,3‐dimethylindole 1 with ethyl carbonate to prepare tris‐(1,3‐dimethyl‐2‐indolyl)methanol 2. A strong concentration dependence in CDCl3 for H‐2 and N‐methyl protons resonances of 1 is described.
Unsymmetrically Substituted Deoxybenzoins: An Improved Preparative Route
Authors: Badía D. , Domínguez E. , Galarza J. , Lete E. , Martínez De Marigorta E. , Villa M. J. 
Published: September 2010

AbstractA regioselective synthesis of unsymmetrically substituted deoxybenzoins via α‐aminonitriles, establishing the advantage of the use of N,N‐dimethylaminonitriles over the corresponding N,N‐diethylamino derivatives, is reported.
Regio Et Stereochimie De La Cycloaddition D'Une Diarylnitrilimine Sur les Phenyl‐1 N‐Alkyl Dihydro‐1,2 Isoquinoleines Resultats Preliminaires
Authors: Kitane Saïd , Sebban Abdelfatah , Vebrel Joël , Laude Bernard 
Published: September 2010

AbstractThe cycloaddition of a diarylnitrilimine on 1‐phenyl‐N‐alkyl‐1,2‐dihydro‐isoquinolines is regiospecific. The approach of the dipole occurs on the two sides of the dipolarophile except when the size of the N‐alkyl substituent imposes a specific anti approach of the N‐alkyl group.
Introduction D'Un Systeme “Cage” Derive De L'Adamantane Dans Les Acides Carboxyliques, Par Alkylation En Catalyse Par Transfert De Phase Et Par Une Methode Non Catalytique
Authors: Hedayatullah Mir 
Published: September 2010

AbstractThe syntheses of new carboxylic esters of general type RCO2‐CH2CO‐Ad (Ad=1‐adamantyl), where R may be aliphatic or aromatic, have been achieved in high yield by reaction of the corresponding acides with an appropriate derivative of adamantane under phase‐transfer conditions or by a noncatalytic procedure. The influence of the lipophilicity of the catalyst on the course of the alkylation of benzoic acide is discussed.
Synthesis of Anionic and Hydrophobic Derivatives of Ethidium Bromide as Potential New Trypanocydes
Authors: Loccufier J. , Schacht E. 
Published: September 2010

AbstractThis paper describes the synthesis of anionic and hydrophobic derivatives of 3,8‐diamino‐5‐ethyl‐6‐phenyl phenantridium bromide (ethidium bromide, homidium). Evidence for regioselective acylation is provided.
Stereochimie De La Reaction Du β‐Cyclocitral Avec Les Organozinciques Issus Des γ‐Bromosenecioates De Trimethylsilyle
Authors: Bellassoued M. , El Borgi A. , Gaudemar M. 
Published: September 2010

AbstractBoth Z et E γ‐bromosenecioic trimethylsilyl esters react with ß‐cyclocitral in the presence of zinc and at low temperature (−40°C) to give the hydroxyacid 2 as the main product. When the reaction is carried out at reflux of THF for 30 mn, the lactone 4 is exclusively obtained. An extended heating of the reaction mixture leads to the acid 5.
Synthesis of 5‐Aryl‐ and 5‐Alkyl‐4‐Ethoxycarbonyl‐2‐Methylthio‐1,3‐Thiazoles from Dimethyl N‐(Ethoxy‐Carbonylmethyl)Iminodithiocarbonate and Dithioesters
Authors: Alonso G. , Alvarez‐Ibarra C. , Orellana G. , Quiroga M. L. 
Published: September 2010

AbstractIn this paper we give account of an efficient synthesis of 5‐aryl‐ and 5‐alkyl‐4‐ethoxycarbonyl‐2‐methylthio‐1,3‐thiazoles from dimethyl N‐(ethoxycarbonylmethyl)iminodithiocarbonate and dithioesters.
Sur L'Utilisation De L'Ion Chromate Comme Agent Oxydant Dans La Synthese De Composes Carbonyles A Partir De Derives Halogenes Actives
Authors: Thuy Vu Moc , Maitte Pierre 
Published: September 2010

AbstractThe reaction between actived alkyl halides and K2CrO4 in DMF or DMSO provides a convenient synthetic route to corresponding carbonyl compounds.
Complexes of Tetrahydrothiamine and its Phosphate Esters With Chromium(III), Iron(III), Cobalt(II), Nickel(II) and Copper(II)
Authors: Hadjiliadis Nick , Yannopoulos Athanassios , De Grave Eddie , Bau Robert 
Published: September 2010

AbstractThe reactions of tetrahydrothiamine (thth) and its mono‐(ththmp) and pyro‐(ththpp) phosphate esters, with metal halides of NiII, CuII, CoII, CrIII and FeIII were studied in organic solvents. Complexes of the formulae NiL(H2O)4Cl2, CuL(H2O)Cl2, CoL(H2O)3Cl2, CrL(H2O)2Cl3 and FeL(H2O)3Cl3, with L thth, ththmp and ththpp, were isolated as solid adducts. An attempt was made for their characterization, with elemental analysis, conductivity and magnetic susceptibility measurements, ir, uv‐vis and Mössbauer spectra in the case of the FeIII complexes. The N atom of the pyrimidine moiety of the ligands is proposed as a possible coordination site, in the case of NiII, CuII and CoII complexes.
Spectrophotometric and First Derivative Spectrophotometric Determination of Copper With 1‐Phenyl‐1,2‐Propanedione‐2‐Oxime‐1‐Guanylhydrazone
Authors: Salinas Francisco , Nevado Juan Jose Berzas , Valenzuela María Isabel Acedo 
Published: September 2010

Abstract1‐phenyl‐1,2‐propanedione‐2‐oxime‐i‐guanylhydrazone (FPOG) reacts with copper (II) in a basic medium to form an 1:1 yellow complex having an absorption maximum at 405 nm. A detailed study of the characteristics of this complex has been carried out and a spectrophotometric method for the determination of copper (II) at the 0.2‐13.0 ppm level is proposed. Molar absorptivity at 405 nm is 5.6×103 l.mol−1. cm−1 and the relative error (P=0.05 and n=9) is 0.7%. The selectivity of the method has been increased by employing first derivative spectrophotometry. By the use of the derivative approach copper(II) can be determined in aluminium alloy and aluminium bronze.
Spectres RMN‐1H Et‐13C De Phenyl‐1‐Propanediamines‐1,2 Derives De L'Ephedrine Et De Leurs Imidazolidines
Authors: Tytgat D. , Gelbcke M. 
Published: September 2010

AbstractA series of N1‐methyl‐1‐phenyl‐1,2‐propanediamines substituted at the nitrogen (N2) by alkyl groups (CH3, C2H5, i‐C3H7, t‐C4H9) and the corresponding imidazolidines from formaldehyde have been synthesized. The study of their 1H‐and 13C‐NMR spectra allowed the differentiation of the diastereoisomers in these two series.
A Facile New Method for the Preparation of Aromatic Diisothiocyanates
Authors: Garín J. , Meléndez E. , Merchán F. , Merino P. , Tejero T. 
Published: September 2010

AbstractIn the present communication we describe a new facile method for the preparation of aromatic diisothiocyanates. The main advantage of this method is a one‐pot procedure from bis(dithiocarbamates) compared with the methods described in the literature.
Synthesis of Large‐Sized Sapo‐5 Crystals With Silicon Occupying Predominantly Phosphorus‐T‐Sites
Authors: Finger G. , Jahn E. , Zeigan D. , Zibrowius B. , Szulzewsky K. , Richter‐Mendau J. , Bülow M. 
Published: September 2010

AbstractSilicoaluminophosphates of type SAPO‐5 with low content of silicon have been synthesized forming single hexagonal prisms up to 100 micrometers. By 29Si MAS NMR technique it is proved that in these samples silicon predominantly occupies framework sites which should give rise to catalytic activity.
Determination Voltamperometrique Des Ions Bi3+ A L'Aide D'Une Electrode Tournante a Renouvellement Constant De La Surface
Authors: Stoytcheva Margarita , Noninski Christo 
Published: September 2010

AbstractOn a étudié l'influence de différents facteurs‐vitesse de rotation de l'électrode, concentration de l'électrolyte indifférent (KCl, KBr, NaF, NH3+NH4Cl), concentration du dépolarisant, température, etc. sur le courant de diffusion et le potentiel de demi‐vague, enregistrés lors de la réduction des ions Bi+3 sur une électrode tournante à renouvellement constant de la surface. On a démontré que cette électrode peut être employée pour la détermination qualitative et quantitative du dépolarisant cité.
Synthesis of 1‐Amino‐5‐(Substituted)Amino‐1,2,3‐Triazoles
Authors: L'abbé Gerrit , Bruynseels Maria , Beenaerts Linda , Vandendriessche Anna , Delbeke Pieter , Toppet Suzanne 
Published: September 2010

Abstract1‐Amino‐5‐(substituted)amino‐1,2,3‐triazoles (3) are directly produced by heating 1‐aryl‐5‐chloro‐1,2,3‐triazoles (1) with hydrazine. The 5‐hydrazinotriazoles 2 are presumably formed first, but rearrange spontaneously under the reaction conditions. The structures of the products were established principally on the basis of 13C NMR analyses.
Thermal Characterization of Liquid Crystalline Materials
Authors: van Ende P. , Groeninckx G. , Reynaers H. , Leuven K. U. 
Published: September 2010

AbstractDuring the last years, there has been a significant interest in the field of liquid crystalline components, polymers in particular.[1,2] There is a definite need to use a wide range of methods to characterize these materials. Thermal properties need to be examined properly in order to obtain the glass‐transition temperature, melting, clearing and crystallization temperatures.The first part of this paper will give an introduction to the basic principles of the liquid crystalline state. The outstanding properties as well as the required chemical structure will be discussed. The second part deals with the characterization of these materials by means of optical, thermal and scattering techniques available in our laboratory.
α‐Arylation of Aldehydes Via α‐Chloroaldimines
Authors: Kimpe Norbert De , Zi‐Peng¶ Yao , Schamp Niceas 
Published: September 2010

Abstractα‐Chloroaldimines are arylated at the α‐position under Friedel‐Crafts conditions via the presumptive intermediacy of α‐imidoylcarbenium ions. Aluminium (III)chloride in arenes cleanly converted α‐chloro‐α‐phenylaldimines into α‐aryl‐α‐phenylaldimines. Aliphatic α‐chloroaldimines could only be converted into the corresponding α‐arylaldimines in low to moderate yields due to a lower reactivity and a competitive side reaction, i.e. dehydrochlorination into 1‐aza‐1,3‐dienes. α‐Bromo‐and α‐iodoaldimines were also evaluated under the given Friedel‐Crafts conditions but the results appeared to be negative. The formation of all reaction products (i.e. α‐arylaldimines, 1‐aza‐1,3‐dienes and indolines) from the reaction of α‐chloroaldimines with arenes in the presence of Lewis acids could be explained by the intermediacy of α‐imidoylcarbenium ions, the chemistry of which is discussed to some extent.
Photo‐Oxidation of Some DI‐2‐Benzothiazolymethane Derivatives
Authors: Ramos M. Teresa , Avendaño Carmen , Elguero José , Jimeno M. Luisa 
Published: September 2010

AbstractWe report the photo‐oxidation of some di‐2‐benzothiazolylmethane derivatives and discuss the structure of the isolated methanols and ketones.
Synthesis of Imines From N‐(1‐Halogenoalkyl)Heteroarylium Salts
Authors: Maquestiau A. , Anders E. , Eynde J.‐J. Vanden , D'Orazio P. , Mayence A. 
Published: September 2010

AbstractA comparison is established for the reactivity of benzaldehyde, N‐(1‐chlorobenzyl)pyridinium chloride or N‐(1‐chlorobenzyl)pyrimidinium chloride with several poorly nucleophilic and/or poorly soluble primary amines under mild experimental conditions.
Synthèse Dans La Chimie Des Phenanthridines. II. Préparation D'Une Nouvelle Série D'ω‐(Phenanthridinyl‐6) Alcanoates De Méthyle Ou D'Éthyle
Authors: Lion C. , Boukou‐Poba J. P. , Charvy C. 
Published: September 2010

AbstractA new series of methyl and ethyl w‐(6‐phenanthridinyl) alkanoates is easily synthesised from the acid chloride‐esters ROCO(CH2)nCOCl (n=0,3 to 8; R=Me or Et). Reaction of these with o‐aminobiphenyl leads to the expected amide‐esters which are cyclised to phenanthridines quaternised to the corresponding phenanthridinium salts.
Polyphosphazenes: Synthèse, Propriétés Et Développements Récents
Authors: Potin Philippe , Jaeger Roger De 
Published: September 2010

AbstractThe two step preparation of polyphosphazenes‐polydichlorophosphazene synthesis and later substitution‐allows design of tailor‐made structures. For the past few years, a new route to polydichlorophosphazene and a large range of structures have been disclosed leading to many potential applications.
Synthesis and Properties of Novel Polyetherketones and Polyethersulphones
Authors: Staniland P. A. 
Published: September 2010

AbstractNucleophilic polycondensation procedures developed for the synthesis of ICI's polymers Victrex PES, PEEK and PEK have been utilised to prepare novel polymers whose properties are in some respects superior.Three basic groups of polymers have been examined based on Isophthaloyl, sulphonyl terphenylene and oxyterphenylene units which together yield a spectrum of thermal properties. Glass transition temperatures range from 160°C‐260°C and crystal melting points from 300°C‐400°C.The crystallinity developed in selected examples gives rise to excellent chemical resistance as observed in PEEK and PEK but in many cases the synthetic chemistry is such that the new polymers could be cheaper to produce than these existing resins.
Characterization and Chemical Nucleation of a Polyaryletherether Ketone (Peek)
Authors: Devaux J. , Leblanc D. , Daoust D. , Legras R. , Nield E. 
Published: September 2010

Abstract19NMR spectroscopy has been performed on PEEK samples in sulphuric acid, revealing that most chain ends are fluorine. Different chemical shifts have been observed on sulphonated samples due to already demonstrated long range shielding effects. The method appears suitable for Mn determination.Substitution of F chain ends, followed by 19NMR, appeared feasible leading to alkaline sulphonate end groups. Ionic chain ends associations act as seeds for nucleation. Fast crystallizing PEEK and PEK are thus obtained. This is a new demonstration of the concept of Chemical Nucleation.
Realisation of a Bioartificial Pancreas Using a New Performant Asymmetric Membrane
Authors: Schué F. , Aoumar A. Ben , Clarotti G. , Sledz J. , Orsetti A. , Paleirac G. 
Published: September 2010

AbstractThe results of this work show a new asymmetric membrane very performant, characterized by an exceptional deformability, a good pressure strength, a high permeability and a satisfactory permselectivity.Its interesting specific anticoagulant activity is a contribution to the realization of a “new bio‐artificial pancreas”.
Possibilités Offertes Par Le Traitement Par Plasma Pour Augmenter L'Hémocompatibilité Des Membranes D'Ultrafiltration
Authors: Clarotti G. , Schué F. , Sledz J. , Ait Aoumar A. Ben , Geckeler K. , Orsetti A. , Paleirac G. 
Published: September 2010

AbstractCe travail est financé par la bourse nº ST2*35I du programme Stimulation de la Commission des Communautés Européennes
Proprietes Electriques Du Metavanadate De Potassium
Authors: Pouchards M. , Theobald F. , Theobald J. G. , Ammari M. 
Published: September 2010

AbstractWe measure the piezoelectric (d=65.10−12 m V−1) and pyroelectric (P=2,5 10−6 Cb m−2 °K−1) properties of K2 V3 O8. We try to obtain a coherence between these results, using the structure of K2 V3 O8 previously determined.
Complexes of Group IIb Metals With Dithiooxamides V‐Vibrational Spectra And Thermal Analysis of the CdLX2 Complexes
Authors: Geboes Peter , Plakatouras John , Desseyn Herman O. 
Published: September 2010

AbstractIn acid media, CdX2 forms non‐electrolyte CdLX2 (L=DTO, NN′DMDTO, TMDTO; X=Cl, Br, I) complexes with dithiooxamides. The ligands act as bidentates with S,S coordination.A thorough vibrational analysis (i.r. and Raman) has been performed for the Cd(H2NCSCSNH2)X2 (X=Cl, Br, I), the Cd(CH3NHCSCSNHCH3)X2 (X=Br, I) and the Cd[(CH3)2NCSCSN(CH3)2]X2 (X=Cl, Br, I) complexes, by NH/ND and CH3/CD3 isotopic substitution. Stereochemistries varying from tetrahedral to octahedral structures are proposed based on spectroscopic evidence and the positions of the metal‐ligand vibrations can be explained in terms of the HSAB principle.The thermal behaviour of the complexes has been studied, using isothermal as well as non‐isothermal techniques.
Cyclic Voltammetric of the 4,NO2 Pyrazolepentacyanoferrate and 4,Br Pyrazole‐Pentacyanoferrate Complexes at Different pH Values. The Ko and α Values
Authors: López Fernández V. 
Published: September 2010

AbstractCyclic voltammetric studies of the oxidation of the 4,NO2 pyrazole‐pentacyanoferrate and 4,Br pyrazole‐pentacyanoferrate complexes were carried out in a platinum rotating electrode at different pH values. For these complexes the ko and α values have been determined. Average values of ko=0.58 10−1 cm/s and ko=0.98 10−1 cm/s respectively are obtained.
Chemical Analysis of Zairian Coastal Seawater
Authors: Mulenga M. , Monama O. , Kabungu Y. , Kalala K. , Yowa K. , Dorebaba R. 
Published: September 2010

AbstractSalt composition of seawater along Zairian coast between 4,5° and 6° S was determined by volumetric and photometric methods. The concentration of NaCl per litre was found to be approximately 18 g/l.
Captodative Substituent Effects. ‐ Part 491 ESR Study of Carbon Centered Transient Radicals Using α‐Tert.Butylthioacrylonitrile as Radical Trap
Authors: Merényi Robert , Janousek Zdenek , Viehe Heinz G. , Mignani Serge 
Published: September 2010

AbstractA method for trapping of transient carbon centered radicals is proposed. The ESR spectra of radical adducts 4 deriving from α‐tert.butylthioacrylonitrile 3a give more information concerning the scavenged radical 2 than the other known radical traps.
Synthese Et Etude De La Reactivite Dipolarophilique De L'Oxyde De 1‐Ethoxyphosphindole
Authors: Sedqui Ahmed , Lakhlifi Tahar , Laude Bernard , Amaudrut J. 
Published: September 2010

AbstractA new and efficient synthesis of 1‐ethoxyphosphindole oxide 1 is reported. The dipolarophilic activity of this heterocycle towards three class of 1,3‐dipoles was tested. The cycloaddition reactions are regio‐and stereospecific. Nmr data (1H and 13C) allow us to determine the regio and the diastereochemistry of the cycloadducts.
On the Emission of BaCl2‐Tl Single Crystals
Authors: Tabakova Veneta , Stoicheva Margarita , Trifonova Roumiana 
Published: September 2010

AbstractThe emission of the crystalphosphor BaCl2‐Tl is studied. All the measurements are performed at 53 and 279 K. The emission is excited with photons with different energies in the region of the activator's absorption. Two bands are observed in the spectrum the intensities of which depend on the temperature and the excitation energy. The symmetry of the centres‐associates (Tl+V+) the formation of which is possible in the crystalphosphor is determineda.
Etude D'Electrodes Bifonctionnelles (Electrolyse De L'Eau Et Reduction De L'Oxygene) A Base De Charbons Impregnes De Naphtalocyanine De Molybdene‐Role Du Nickel Superficiel
Authors: Dieng M. , Savy M. , Aaron J. J. 
Published: September 2010

AbstractThe electrolysis of water in alkaline medium has been investigated on electrodes consisting of molybden naphthalocyanine (NPcMo) supported on carbon blacks. The catalyst role of nickel metal incorporated in the carbon black supports in the process of evolution of hydrogen and oxygen has been examined using cyclic voltammetry. The analysis of the peaks of oxidation and reduction at ambient temperature shows an enhancement of activity for the oxygen reduction in the case of NPcMo impregnated electrodes. The state of the chelated nickel depends of the type of electrode used. Thus the existence of nickel naphthalocyanine can be assumed.