bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bonding Trends in Lanthanide Mandelates
Authors: Koppikar D. K. , Soundararajan S. 
Published: September 2010

AbstractThe lanthanide mandelates have been prepared by reacting the lanthanide hydroxides with mandelic acid (HL). The coordination number in these compounds has been discussed on the basis of analytical, infrared and electronic spectral, and thermal data. The mandelates have the general formula, LnL3.nH2O, where n3 for LnLa, Pr, Nd and Sm, and n=2 for LnGd, Dy, Br, Yb and Y. The infrared spectral data reveal that the mandelate ion is coordinated to the lanthanide ions in a bidentate fashion through the oxygen atoms of the carboxylate and the hydroxyl groups. The antisymmetric COO−, the δ OH, and the Ln‐O frequencies in the mandelates show a linear relationship with the ionic radius of the lanthanide ions. The infrared spectral and thermal data afford evidence of the coordination of all the molecules of water to the lanthanide ions. Hence, coordination numbers nine and eight have been assigned to the two sets of mandelates. This conclusion is supported by a study of the shapes of the hypersensitive transitions in the electronic absorption spectra of Nd and Br mandelates. The electronic spectra also suggest that the bonding in these compounds is predominantly ionic.
Analysis of Skeleton Remains, Ascribed to Mary of Burgundy, and of Soil Samples, Recovered from the Central Tomb of the Church of Our Lady, Bruges
Authors: Maenhaut W. , Cornelis R. , Cafmeyer J. , Mees L. 
Published: September 2010

AbstractSkeleton remains and soil samples, recovered from the central tomb of the Church of Our Lady, Bruges, were analyzed for their major, minor and trace element content by means of instrumental neutron activation analysis (INAA), particle induced X‐ray emission (PIXE) and Rutherford back‐scattering (RBS). The results indicated that the reddish brown patinaed surface layer of the skeleton remains had a lead content of the order of 8 to 241, whereas that in the onderlying normal looking bone tissue was only 0.6%. The soil samples, recovered from inside the skull also showed abnormally high lead contents. It is concluded that the lead in the bone is of exogenous origin, ultimately originating from the lead coffin in which the body was buried. It is further suggested that the high lead concentration in the surface layer of the skeleton may be responsible for its reddish brown colour.
Détermination de la structure de la N, N‐diméthyl chloro‐4 benzamide‐oxime C9h11CL N2O
Authors: Tinant B. , Declercq J. P. , Germain G. , van Meerssche M. 
Published: September 2010

AbstractThe structure of the title compound has been investigated using x‐Ray diffractometer intensities in order to determine the configuration of the oxime group. The molecules appear to be in the E configuration. Crystal data are as follow: monoclinic, P2/c; a=6.197(1), b=7.505(2), c=22.975(5)Å, B=99.73(2)°; V=1053.1 Å3; Z=4; Dx=1.25 Mg m−3.
Applications of Mössbauer Spectroscopy to the Study of HDS Catalysts
Authors: Topsøe Henrik , Clausen Bjerne S. , Candia Roberto , Wivel Carsten , Mørup Steen 
Published: September 2010

AbstractMössbauer spectroscopy is one of the new tools which recently have been applied to the study of HDS catalysts. The technique has several unique features which make it especially useful in the study of such catalysts and it has given answers to some of the much debated problems, The studies have yielded insight into, for example.The origin of promotion, (ii) the reason for catalytic synergy, (iii) the nature of the active phase, (iv) the observed similarities between unsupported and supported catalysts, and (v) loading and support effects. The article will review the available literature as well as bring forward some new results.
Pulse Polarographic Studies on the Adsorption of Adenine, Adenosine and Mono, Di and Triphosphate of Adenosine
Authors: Temerk Y. M. , Kamal M. M. 
Published: September 2010

AbstractAdenine, adenosine and adenine mononucleotides (3′‐AMP, 5′‐AMP, 5′‐ADP and 5′‐ATP) were studied at various pH values by means of normal pulse polarographic measurements at the dropping mercury electrode. It was found that adenine, adenosine and adenine mononucleotides yield pulse polarographic peak. From its height and potential conclusions can be made about their adsorption effects at the charged interface. Adsorption effects in normal pulse polarography of adenine, adenosine and adenine mononucleotides were also investigated through the dependence of the pulse polarographic current on various parameters such as pH, temperature, adsorption time and bulk concentration of depolarizer. The potential dependence of the pulse peak height is of bell shaped type with an extended maximum region around the potential of electrocapillary maximum (Eecm) of the supporting electrolyte. For the same bulk concentration the pulse peak height decreases in the series adenosine, AMP, ADP and ATP, i.e. with increasing negative charge. Pulse polarography is particularly valuable for calculation of the values of adsorption parameters for the dilute layer (adsorption coefficient b, free adsorption enthalphy ‐ΔG °, interaction coefficient a) provided the span of the drop life before the application of the pulse is adjusted to a period sufficiently long to reach adsorption equilibrium.
The Infra‐red Spectra of Complexes with Planar‐dithio‐Oxamides Part I: The Neutral PdL2 Complexes
Authors: Hofmans H. , Desseyn H. O. , Aarts A. J. , Herman M. A. 
Published: September 2010

AbstractThe neutral complexes of planar dithio oxamides with Pd(II) are investigated by electronic and infrared spectroscopy and the assignments have been proposed for the fundamental vibrations considering a D2h structure for the R.R.D.T.O. and D.T.O. complexes and a C2h structure for the R.D.T.O. complex. The ligands act as bidentates and coordinate through sulfur giving square planar complexes.
Amino Steroids ‐ Further Studies with Conanine and Heteroconanine Systems
Authors: van De Woude G. , Biesemans M. , van Hove L. , Mertens J. 
Published: September 2010

AbstractTreatment of any of the three following products, heteroconanol methiodide (3′), conanol methiodide (4′) or 18‐dimethylamino‐5α‐pregn‐20‐en‐3β‐ol (1), with a large excess of potassium hydroxide in hot ethylene glycol affords rapidly a mixture of heteroconanol (3, <56%>), conanol (4, <33%>) and the Δ 17(20) isomer of 1 (2,<11%>). The presence of such an isomer has not yet been reported in analogous reactions of related compounds. The Hofmann elimination product 1 is thought to be involved as an equilibrium intermediate in each of the three reactions; its isomer 2 should be formed by base‐catalyzed isomerization and not by eliminative ring fission.
Equilibrium Study of the Mixed Ligand Complexes of Cu(II), Ni(II), Co(II)‐AMINO ACID, 2, 2′‐bipyridyl and iminodiacetic acid with hydroxamic acids
Authors: Janardhan Rao M. , Sethuram B. , Navaneeth Rao T. 
Published: September 2010

AbstractFormation constants of the mixed ligand complexes MAL where M = Cu(II), Ni(II) & Co(II); A = histidine, 2, 2′‐bipyridyl or iminodiacetic acid and L = N, 2′‐diphenylacetohydroxamic acid and 2, 2′‐diphenylacetohydroxamic acid have been determined in water ‐ ethanol (50% v/v) medium. Stability constants of ternary chelate were found to be less than the stability constant value of M:L complex. This trend in log K values is explained on the basis of electrostatic repulsion between the primary and secondary ligands. Remarkable stability of ternary chelates (Cu‐bip‐N,2′‐DPAHA) as indicated by the stabilization parameters are explained in terms of electronic effects, geometry of the complex and steric hindrance.
Détermination de la Structure de la Mopérone: Fluoro‐4' (Hydroxy‐4 p‐Tolyl‐4 Pipéridino)‐4 Butyrophénone
Authors: Tinant B. , Germain G. , Declercq J. P. , van Meerssche M. , Azibi M. , Draguet‐Brughmans M. , Bouché R. 
Published: September 2010

AbstractThe structure of mopérone has been investigated using X‐Ray diffractometer intensities in order to compare the molecular conformation with that of other butyrophenones.Crystal data are as follows: monoclinic, P21/c; a = 16.907(8), b = 21.363(8), c = 10.825(4)Å, β = 96.87(3)°; V = 3882 Å3: z = 8; Dx = 1.22 Mg m−3.
Some Nuclear Reactions of Tropolones
Authors: Komolafe Olusegun Oluwole , Femi‐Onadeko Bankole 
Published: September 2010

AbstractTropolones are of known biological importance,1‐3 both in the plant and animal world. Their synthesis and physico‐chemical properties are therefore of some importance. Tropolone (2‐hydroxy‐2, 4, 6‐cyclo‐heptatriene‐l‐one), by virtue of its inherent aromatic characteristics, would be expected to undergo electrophilic substitution in a facile manner. This is found not to be the case. Substituted tropolones must therefore be produced by new reaction pathways, which necessarily involves more easily accessible intermediates. Such intermediates could possibly be the aminomethyl derivatives of tropolone, which are easily prepared by a simple Mannich condensation. Elaboration of these adducts could lead to more complex tropolones.Nuclear substitution of tropolonesFriedel Crafts reactions of tropolonesAn investigation of Friedel Crafts alkylations and acylations was undertaken using a variety of Lewis acids as catalysts.
Cobalt Molybdenum Catalysts Supported on Sodium Modified λ‐Al2O3: Characterization and Catalytic Activity in the Hydrogenolysis of Thiophene
Authors: Lycourghiotis Alexis , Defossé Camille , Delmon Bernard 
Published: September 2010

AbstractA series of cobalt‐molybdenum‐alumina catalysts was fabricated using as carriers λ‐Al2O3doped with various amounts of sodium.Over these surfaces the H.D.S. of thiophene has been studied. A considerable decrease in the catalytic activity was observed with increasing Na±content.The decrease in the catalytic activity was explained in terms of structural modification of Mo active species caused by sodium.D.R.S., X.P.S. and X‐ray spectroscopies were used to characterize the catalysts.
Preparation of Trans‐5‐Hydroxy‐l‐Pipecolic Acid and Cis‐4‐Hydroxy‐l‐Pipecolic Acid from l‐Baikiain (1, 2, 5, 6‐l‐Tetrahydropyridine‐2‐Carboxylic Acid)
Authors: Callens Roland E. A. , Anteunis Marc J. O. , Reyniers FranÇOise 
Published: September 2010

AbstractZ‐trans‐5‐OH‐L‐pipecolic acid together with Z‐cis‐4‐OH‐L‐pipecolic acid is obtained in a 7:3 ratio by reduction of the oxymercuration product of Z‐L‐baikiain (Z‐1, 2, 5, 6‐L‐tetrahydropyridine‐2‐carboxylic acid). The opposite composition ratio is obtained using mercuric trifluoroacetate, thus giving access to the preparation of either of the two isomers.
Photoelectrochemistry of Ru(bpy)32+ in Basic Medium at SnO2 and Metal Electrodes
Authors: Kirsch‐De Mesmaeker A. , Nasielski J. , Willem R. 
Published: September 2010

AbstractThe influence of the pH on the photoelectrochemical behavior of Ru(bpy)32+ is examined at a highly doped SnO2 electrode. An important photocurrent increase from pH 11 to 13 is explained by the photochemical production of a long‐lived reductant generated from Ru(bpy)32+. Photocurrent observations at metallic electrodes and the photogalvanic cell behavior confirm this interpretation. Furthermore, a modification of the SnO2 electrode by the ruthenium complex has been pointed out.
Molecular Structure Analysis of Monoamine Oxidase Inhibitors IV. Crystal Structure of 3‐[4‐[(3‐nitrophenyl)‐methoxy] phenyl]‐6‐methoxymethyl‐2‐oxazinone: C19H20N2O6
Authors: Durant F. , Bufkens F. , Evrard G. , Lamotte C. 
Published: September 2010

AbstractThis paper is the fourth of a general study of structural properties of a series of new Monoamine Oxidase Inhibitors (MAOI's). The results of the X‐ray crystal structure analysis of an oxazinone derivative are related to and compared with those previously reported for oxazolidinone homologues.
Extraction, Assay and Conversion of NH. A Preparative Procedure for Isotopic Enrichment Determination
Authors: Grognet Pierre , Malaisse‐Lagae Francine , Sener Abdullah , Malaisse Willy J. 
Published: September 2010

AbstractA method is described for the extraction of NH4+ from biological samples. This method can be combined with the enzymatic conversion of NH4+ to glutamate, which can then be used for measuring 15N isotopic enrichment. Emphasis is laid on the difficulties encountered when the samples contain NH4+ together with the amide derivative of monoaminodicarboxylic acids.
Diluent Influence on the Extraction of some Transition Metalchloride Complexes with Triïsoöctylamine
Authors: Verhaege M. , Claus G. , van Peteghem A. 
Published: September 2010

AbstractRecently, chlorinated high density hydrocarbons have been proposed as diluent or as additive to more common solvents for the liquid‐liquid extraction of some base metals (1,2,3).In this communication the extraction curves of some transition metals from chloride solutions with a currently used anionexchanger (triisoöctylamine) solved in perchloroethylene are presented. The results are compared with those obtained for more commonly used solvents in liquid‐liquid extraction: SHELLSOL K (an aliphatic diluent) and SOLVESSO 150 (an aromatic diluent).
Pyridines. Partie X1 ‐ Synthèse de Pyridyl‐ et Quinolylenamidines par Condensation Entre Composes Organolithiens et Benzonitrile. Nouveaux Intermediaires pour Réactions D'Heterocyclisation
Authors: Compagnon Paul‐Louis , Gasquez Françoise , Compagnon Odette , Kimny Tan 
Published: September 2010

AbstractA series of methylpyridyl‐ and (methyl) quinolylphenylvinylbenzamidines has been synthesized by condensation of organopolylithium compounds derived from polymethylpyridines and ‐quinolines with benzonitrile. In diethyl ether, beside the enamidines, the reaction gives enolizable ketones. Triphenylimidazole, triphenyl‐s‐triazine and triphenylpyrimidine are isolated in the case of benzylmagnesium chloride. Possible routes leading to the various products are suggested. In diethyl ether, the conditions which give the enamidine derivatives in useful yields have been established. In liquid ammonia, on the contrary, no polycondensed products were isolated. The intermediate enamine and enamidine anions are trapped in diethyl ether by acylation of the reaction mixture before hydrolysis. With benzoyl or acetyl chloride, ethyl chloroformate, various C‐ and N‐acylated products (enolizable β‐diketones, enamides, acylenamides, N‐acylenamidines) and their cyclization products (pyrimidines) are obtained. The latter are also prepared from the isolated enamidines and benzoyl chloride.
Résultats Récents en Chimie Hétérocyclique du Germanium
Authors: Satge Jacques 
Published: September 2010

AbstractDivalent germanium species: germylenes and germanium doubly bonded species (GeY YC, O,S,N‐,P‐,Ge) are powerfull synthetic reagents in organometallic chemistry. The germylenes exhibit properties analogous to those of carbenes and have been shown to insert into various ♀ bonds such as: carbon‐heteroelement, metal‐carbon, metal‐heteroelement, etc.… of heterocyclic derivatives with ring expansion. The additions of germylenes on various unsaturated compounds (alkenes, alkynes, dienes, carbonyl compounds, imines, nitrosobenzene) lead to cycloadducts which have generally a low stability except in the case of dienes. The doubly bonded germanium species are highly reactive and widely used in organometallic synthesis in various types of reactions such as: ‐ addition (or insertion reactions) on various ♀ bonds of organometallic compounds,‐insertion reactions with ring expansion into small organic rings,‐cycloaddition reactions on 1‐2, 1‐3 and 1‐4 dipolar reagents‐condensation and exchange reactions.The mechanism and the stereochemistry of some reactions are discussed.
Coordination compounds of heterocyclic AZO derivatives II‐transition metal chelates of some pyrazolone AZO dyes
Authors: Mahmoud M. R. , Adam F. A. , Yousef K. , El‐Haty M. T. 
Published: September 2010

AbstractThe chelates of some 4‐arylazo‐3‐amino‐pyrazolone derivatives with Mn(II), Fe(III), Zr(IV), Pd(II) and Ag(I) are prepared and characterized. It is concluded that the ligands and the complexes exist mainly in the hydrazone‐keto form. It is confirmed that such compounds are coordinated to the metal ion as monovalent bidentate ligands, L−, and the bonding sites are the oxygen of the carbonyl group and the α‐nitrogen of the arylazo group.
Sedum alkaloids, IV, the X‐ray crystal and molecular structure of sederine hydrochloride and the absolute configuration of sederine
Authors: Piccinni‐Leopardi Carla , Germain Gabriel , van Meerssche Maurice , Colau Brigitte , Hootele Claude 
Published: September 2010

AbstractThe absolute configuration of the three asymmetric atoms of sederine, a minor alkaloid isolated from Sedum acre, has been established through the use of Horeau's method together with a study by X‐ray diffraction of sederine hydrochloride.
Spectrométrie de Masse Des α‐Diazoimines. Réarrangement Des Cations‐Radicaux D' α‐Iminocarbenes en Phase Gazeuse
Authors: Maquestiau A. , Flammang R. , Meyrant P. , Regitz M. , Arnold B. , Schubert H. 
Published: September 2010

AbstractThe study of the mass spectra of six α‐diazo‐N‐cyanoimines and the collision‐induced dissociation/mass‐analysed ion kinetic energy spectra of their [M‐N2]+· fragment ions demonstrate the decay sequence: [α‐diazoimine]+·→ α‐iminocarbene]+·→ [ketenimine]+. This last ion is shown to be structurally identical to the one formed by electron‐induced cycloreversion of the ketenimine‐benzylideneaniline cycloadduct.
High Yield Synthesis of Filicinic Acid, Based on the Polychlorination of 4,4‐Dimethyl‐2‐Cyclohexenone Part II: Conversion of 2,3,5,6‐tetrachloro‐4,4‐dimethyl‐2,5‐cyclohexadienone into filicinic acid and related cyclohexadienones
Authors: De Buyck L. , De Kimpe N. , Verhé R. , Schamp N. 
Published: September 2010

AbstractFilicinic acid (5) was prepared in 75‐80% overall yield from 4,4‐dimethyl‐2‐cyclohexenone (1). The key intermediate, tetrachlorodienone 2, underwent facile substitution of both β‐chlorine substituents by methoxide affording the bis enol ether 3 which was converted into dichlorofilicinic acid 4 in hot 85% sulfuric acid. Monohydroxy derivatives were obtained by treatment of 2 or 3 with hydroxide. Palladium‐catalysed low‐pressure hydrogenation of 4 under appropriate conditions produced monochlorofilicinic acid, filicinic acid or 5‐hydroxy‐4,4‐dimethyl‐1,3‐cyclohexanedione (8) with high selectivity.
The crystal structure of manganese(II)‐(±)‐1‐malate trihydrate
Authors: Lenstra A. T. H. , Dillen J. 
Published: September 2010

AbstractRacemic manganese(II) (±)‐1‐malate trihydrate crystallizes in the space group Pcab, with Z=8 and a=14.201(8), b=14.656(4), c=8.265(5)Å. The Mn‐ion is surrounded by six oxygen atoms forming an octahedron, slightly distorted by the rigidity of one malate ion, acting as a bidentate ligand. The malate ion has the trans conformation in the OOC‐CH2‐CHOH‐COO chain. The racemic manganese salt and its optically active counterpart are practically equal in terms of the Mn‐coordination and the geometrical details of the malate anion.
Structure du Cholestadiene‐4,6 One‐3, C27H43O
Authors: Dupont L. , Dideberg O. , Krzyminiewski R. 
Published: September 2010

AbstractThe structure of cholesta‐4,6‐diene‐3‐one has been investigated using X‐ray diffractometer intensities. The final conventional R value is 0.06.Crystal Data are as follow: orthorhombic, P212121, a=25.591 (5), b=15.089 (4), c=6.334 (3)Å, V=2445.8A3, Z=4. Dx=1.04Mgm−3, μ=4. 6cm−1.
Long‐acting contraceptive agents: X‐Ray study of levonorgestrel esters
Authors: Crabbé Pierre , Schlemper Elmer O. 
Published: September 2010

AbstractThe X‐ray crystal structure determinations of levonorgestrel (1) and its esters (2) to (7) have been performed in order to assign the molecular features and attempt to correlate the conformation of the molecules with their long‐acting contraceptive activity.In the most active compounds, i.e., levonorgestrel butyrate (4), cyclopropylcarboxylate (6), and cyclobutylcarboxylate (7), the unusual orientation of the ester chains seems to affect the entire steroid framework. The stereochemistry of ring A is only slightly modified while the tetracyclic skeleton exhibits a more planar conformation than that of levonorgestrel (1) or the other esters (2), (3), and (5), and the ester grouping shields the 0 (17) ester position much more in esters (4), (6), and (7). Since levonorgestrel (1) and norethisterone (8) have very similar conformations, additional factors, different from the molecular geometry, seem to be responsible for the dramatic long‐acting contraceptive properties associated with these esters.
Contribution a L'Étude du Comportement du Chlore et du Brome Dans Les Solvants Nucléophiles
Authors: De Meyer M. , Levert J. M. , Vanclef A. 
Published: September 2010

AbstractIn this paper, we study the oxydant concentration stability of diluted halogen solutions of bromine, chlorine in organic solvents: acetonitrile, nitromethane, N,N‐dimethylformamide, N,N‐dimethylacetamide, 1 methylpyrrolidinone‐2, tetrahydrofuran, dimethylsulfoxide, tetramethylurea and tetramethylthiourea.Raman spectroscopy examinations of halogen Solutions show undoubted formation of trichloride and tribromide ions in N,N‐disubstituted amide solvents. This specific chlorine solvation explains the immonium chloride formation observed during styren chloration in N,N‐dimethylformamide. Bromine solvation in dimethylsulfoxide and other nucleophilic solvents are also studied.
Étude Comparative de la Réactivité de L'Acetoacetate D'Éthyle et du 3‐Aminocrotonate D'Éthyle Vis‐A‐Vis de Composes Pyrazoloniques
Authors: Maquestiau A. , van Haverbeke Y. , Vanden Eynde J.‐J. 
Published: September 2010

Abstract1‐phenyl‐3‐methylpyrazolin‐5‐one, 1,5‐dimethylpyrazolin‐3‐one and 1‐phenyl‐pyrazolidin‐3,5‐dione react with ethyl acetoacetate to yield pyrano [2,3‐c] pyrazole‐6‐ones. Starting from 1‐phenyl‐3‐aminopyrazolin‐5‐one or from 1‐methyl‐5‐aminopyrazolin‐3‐one, pyrazolo [3,4‐b] pyridin‐6‐ones are obtained.When ethyl 3‐aminocrotonate instead of ethyl acetoacetate is used, the course of these reactions remains the same in most cases but yields are always higher.
New Applications of Dipolar Cycloaddition Chemistry Toward the Synthesis of Heterocycles
Authors: Padwa Albert , Chen Yon‐Yih , Koehler Konrad F. , Tomas Miguel 
Published: September 2010

AbstractA new method for the preparation of β‐lactams has been developed. The protocol involves 1,3‐dipolar cycloaddition of nitrones with nitro substituted alkenes followed by a subsequent reorganization of the resulting 5‐nitroisoxazolidine isomer. The utilization of α‐silyl substituted amines as azomethine ylide equivalents has also been explored.
Hydrogen Bonding and Protonation Site in N,N‐Diethylnicotinamide
Authors: De Taeye J. , Maes G. , Zeegers‐Huyskens T. H. 
Published: September 2010

AbstractThe hydrogen bonded complexes between N,N‐diethylnicotinamide and proton donors such as phenol derivatives or hydrochlorid acid have been studied by infrared spectrometry. The thermodynamic parameters, the ΔνOH values and the shift of the νCO band to lower frequencies indicate that with phenol derivatives (pKa=10.2 ‐7.7 ), normal CO…HO hydrogen bonds are formed. The spectra show that the adduct with HCI is a proton transfer complex and that the protonation occurs at the nitrogen atom of the pyridine ring.