bluuebunny/crossref_metadata_2025 huggingface dataset:
A Primary Hydrogen-Deuterium Isotope Effect Study on the Carbonyl Elimination Reaction of 9-Fluorenyl Nitrate with Various Bases
Authors: Smith Peter James , Noble Lorraine Marion
Published: May 2006

The carbonyl elimination reaction of 9-fluorenyl nitrate with various nitrogen bases in anhydrous ethanol at 0 °C was examined. In all cases fluorenone was formed in 100% yield indicating that there was not any substitution. A reasonable Brønsted plot was obtained for reaction promoted by structurally similar bases with β = 0.84 which suggests a product-like transition state. As well, deviations from the Brønsted plot are discussed. Primary hydrogen-deuterium isotope effects were measured for reaction promoted by 11 different amine bases. A reasonable correlation was obtained for structurally similar bases when a plot of kH/kDvs. pKa was made. The conclusion is reached that when kH/kD reaches a maximum, ∼9.2 at 0 °C, it remains unchanged and hence is a poor measure of transition state geometry. As well, very poor correlations are found when the abstracting base is tertiary which leads to the conclusion that a comparison of kH/kD values is not warranted for structurally different bases.
Nuclear Magnetic Resonance Studies on the Acetolysis and Trifluoroacetolysis of Trianisylvinyl-2-13C Bromide
Authors: Oka Mitsuo , Lee Choi Chuck
Published: May 2006

The product from the reaction of trianisylvinyl-2-13C bromide (3—Br-2-13C) with HOAc–AgOAc or with CF3COOH–CF3COOAg was converted to 1,2,2-trianisylethanol-x-13C (4—x-13C) and examined for isotopic scrambling by the use of relative intensity ratios in the c.m.r. spectra with the CH3O absorption as the internal standard, or by the intensities of the 13C satellites in the p.m.r. spectra. About 20 and 50% rearrangements of the 13C-label from C-2 to C-1 were found, respectively, for the acetolysis and trifluoroacetolysis. The results are in accord with the suggestion that there may be a competition between 1,2-aryl shifts in the triarylvinyl cation or ion-pair and the reaction of the ion with solvent to give product.
Electrochemical Behavior of the Lead Electrode in HCl and NaCl Aqueous Electrolytes
Authors: Barradas Remigio Germano , Belinko Keith , Ambrose John
Published: May 2006

The electrochemical properties of lead electrodes in aqueous chloride solutions were experimentally investigated over a range of 0.1 to 6.0 M HCl with the aim of extending previous work carried out only at 1.0 M HCl concentration. Experimental results using the rotating disc electrode technique, cyclic voltammetry, galvanostatic and potentiostatic charging conditions were employed in conjunction with spectroscopic studies of the electrolyte and X-ray powder diffraction analyses of electrode surface products. Experiments were also carried out in simulated sea water (3% NaCl) at different pH and compared with results obtained using HCl at the same molar concentration. At all chloride concentrations the overall reaction led to the formation of PbCl2 on the electrode surface, with the exception that in NaCl solutions where pH ≥ 6.5, Pb(OH)Cl was found to be one of the products. For concentrations of less than 0.4 M HCl, our results indicated that the diffusion of chloride ions to the electrode surface was the limiting factor in the formation of a passivating PbCl2 layer. At concentrations of about 0.7 M HCl, the electrochemical behavior showed a pattern of results which were interpreted in terms of a "passivation–dissolution" competitive mechanism consistent with the solubility minimum of PbCl2 in aqueous chloride solutions.
Substituent Effects in the Thermal Isomerization of 1,2-Dicarbonyl Derivatives of 3,6-Bridged 1,2,3,6-Tetrahydropyridazines
Authors: Campbell John A. , Harris Ian , Mackay Donald , Sauer Timothy D.
Published: May 2006

The Diels–Alder adducts of cyclopentadiene and azodiacyls or azodiaroyls isomerize to 1,3,4-oxadiazines at rates which show a trend qualitatively related to the rotation rates of the corresponding N,N-dimethylamides. The isomerizations probably occur by a cyclic concerted mechanism.The ring substituents in the adducts of 1,4-dimethyl-2,3-diphenylcyclopentadiene and azodibenzoyl or azodiacetyl accelerate the isomerization; the kinetic evidence supports a cyclic intermediate in the reaction in isooctane as solvent but is more consistent with a dipolar intermediate in aqueous ethanol.Some generalizations about the effect of substituents on the isomerization are presented on the basis of these and earlier experiments.
Nuclear Magnetic Resonance Chemical Shifts of some Monosubstituted Isothiazoles
Authors: Wasylishen Roderick E. , Clem Thomas R. , Becker Edwin D.
Published: May 2006

Carbon-13 and proton chemical shifts have been measured for several monosubstituted isothiazoles. Substituent effects upon these chemical shifts are compared with those observed for monosubstituted benzenes, pyridines, and thiophenes. In general the observed substituent effects in the isothiazoles and thiophenes closely parallel one another. Correlations between the observed carbon-13 Chemical shifts and CNDO/2 calculated charge densities are examined.
A Kinetic Electron Spin Resonance Study of the Transfer of a Hydrogen Atom from α-Tetralin Hydroperoxide to a Tertiary Alkylperoxy Radical
Authors: Chenier J. H. B. , Howard J. A.
Published: May 2006

A kinetic electron spin resonance spectroscopic study of the reaction of tertiary alkylperoxy radicals with α-tetralin hydroperoxide is reported. The absolute rate constants for this hydrogen atom transfer process (k1) are given by the equation log (k1/M−1 s−1) = (6.0 ± 0.5 ) − (4.5 ± 0.5 )/θ, where θ = 2.303 RT kcal mol−1.A significant isotope effect is obtained when the hydroperoxidic hydrogen is replaced by deuterium, e.g. k1H/k1D at 21° = 9.Other alkyl hydroperoxides, e.g. triphenylmethyl, s-butyl, and 9,10-dihydro-9-anthracyl have approximately the same reactivity to t-ROO• as α-C10H11OOH.
Mass Spectrometric Studies of the Ionization and Thermal Decomposition of Tungsten π-Cyclopentadienyl Tricarbonyl Dimer
Authors: Krause J. R. , Bidinosti D. R.
Published: May 2006

The ionization and thermal decomposition of tungsten π-cyclopentadienyl tricarbonyl dimer [WC5H5(CO)3]2 was investigated using a mass spectrometer fitted with single and double cell molecular flow inlet systems.The electron impact mass spectrum and appearance potentials for the principle ions in the spectrum have been measured and recorded.The enthalpy change for the dissociation[Formula: see text]obtained from van't Hoff plots of the temperature dependence of the equilibrium constant was found to be 234.4 ± 3.8 kJ/mol. This result was substantiated by an electron impact value of 221.0 ± 20.1 kJ/mol based on an ionization potential for ·WC5H5(CO)3 of 7.66 ± 0.05 eV measured in the high temperature studies.
Concerning the Problem of Stereospecific Glycosylation. Synthesis and Methanolysis of some 2-O-Benzylated D-Galactopyranosyl and D-Galactofuranosyl Halides
Authors: Fréchet Jean M. J. , Baer Hans H.
Published: May 2006

Acetolysis of 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-galactopyranose (3) followed by de-O-acetylation and p-nitrobenzoylation gave 2,3,4-tri-O-benzyl-1,6-di-O-p-nitrobenzoyl-β-D-galactopyranose (4) which was converted into 2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-D-galactopyranosyl bromide (5). Benzylation of methyl 4,6-O-benzylidene-α-D-galactopyranoside (6) gave the 2,3-dibenzyl ether (7) which was hydrolyzed to 2,3-di-O-benzyl-D-galactose (8). p-Nitrobenzoylation of 8 furnished 2,3-di-O-benzyl-1,5,6-tri-O-p-nitrobenzoyl-β-D-galactofuranose (9) and an isomer, presumably a β-pyranose derivative (10). Compound 9 was converted into 2,3-di-O-benzyl-5,6-di-O-p;-nitrobenzoyl-β-D-galactofuranosyl bromide (11) and chloride (12). The new halides 5, 11, and 12 as well as known 2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl bromide (1) and chloride (2) were subjected to methanolysis in dichloromethane solution in the presence of methanol alone and in the presence of tetrabutylammonium bromide, mercuric cyanide, and silver tetrafluoroborate, respectively, and the ratios of anomeric glycosides produced were examined by n.m.r. spectroscopy. Factors influencing stereoselectivity in these reactions are discussed. The new methyl α- and β-glycosides derived from 5 (13 and 14) and the methyl α-glycoside (15) produced from 11 and 12 were isolated, and methyl 2,3,5,6-tetra-O-benzyl-α-D-galactofuranoside (16) was prepared for the first time.
Homogeneous Hydrogenation of Unsaturated Carboxylic Acids Using Chlororhodate(I) Complexes and Rhodium(I) Diethylsulfide Complexes
Authors: James Brian R. , Ng Flora T. T.
Published: May 2006

N,N-Dimethylacetamide solutions of the cyclooctene complex [Rh(C8H14)2Cl]2, in the presence of excess chloride or diethylsulfide, are effective for the homogeneous hydrogénation of unsaturated carboxylic acids at ca. 80 °C and 1 atm H2. Kinetic studies on the hydrogenation of maleic acid are consistent with a rate determining step involving oxidative addition of H2 to square planar rhodium(I) olefin species. Rate constants and activation parameters agree with those determined previously from similar studies using corresponding rhodium(III) complexes and give confirmation that rhodium(I) catalysts are involved in the rhodium(III) systems. Discussion of the systems is limited by the somewhat uncertain nature of the catalysts; however, chlororhodate(I) species are involved in the chloride solutions, and bis(diethylsulfide) complexes appear likely in the sulfide systems.
Reactions du Phenyl-1 dimethyl-3,4 phosphole avec divers chlorures d'acides aromatiques
Authors: Mathey François , Thavard Daniel , Bartet Bernard
Published: May 2006

1-Phenyl-3,4-dimethylphosphole with water and substituted benzoyl chlorides or 2- and 3-thienyl chlorides is expanded into 2-hydroxy-l,2-dihydrophosphorines. This reaction is particularly affected by steric effects. It fails with aliphatic acid chlorides. These results are not fully explained by a competition between the expansion reaction and the hydrolysis of the chlorides. A complementary explanation is proposed. The 2-hydroxy-1,2-dihydrophosphorines are in turn expanded into 1-oxa-2-phosphacyclohepta-4,6 dienes with catalytic amounts of NaH. This other expansion reaction seems to be only weakly affected by steric but more strongly by electronic effects. It fails with thienyl derivatives. Nuclear magnetic resonance data are given and discussed for all the new products. Large P–C–OH couplings in hydroxydihydrophosphorines are noteworthy.
The Observable Thirtyfold Degenerate Camphenehydro Cation. A Stereospecific exo-3,2-Methyl Shift and endo-6,2(exo 6,1)-Hydride Shift
Authors: Haseltine R. , Huang E. , Ranganayakulu K. , Sorensen T. S.
Published: May 2006

The observable camphenehydro cation 2 has been prepared and is shown to undergo two degenerate rearrangements, both well known in an indirect sense from many studies on the racemization of camphene. The results from both methods are compared and some advantages of the direct method are given; in particular it is shown that the 3,2-methyl shift is highly stereospecific. An eventual irreversible rearrangement of 2 is observed and the ion products characterized. A computer is used to systematically investigate the shortest paths from reactant to product ions.
The Mechanism of Formation of Hexene-1 in the Photolysis of Ethylene at 185 nm
Authors: Simon M. , Back M. H.
Published: May 2006

In the photolysis of ethylene at 185 nm the rate of formation of hexene-1 has been measured. The ratio of the rates of formation of hexene-1 to butane varied from 0.6 to 1.4 at 298 K and fell to about 0.25 at 153 K. It is suggested that hexene-1 is formed by successive additions to ethylene to give hexamethylene which isomerizes to hexene-1.[Formula: see text]This interpretation is consistent with the effect of pressure of ethylene and absorbed light intensity on its rate of formation.
The Origin of the Methyl Radical in the Photolysis of Propane at 123.6 nm
Authors: Gawłowski Janusz , Herman Jan A. , Gagnon Pierre
Published: May 2006

The isotopic composition of methane formed in photolysis at 123.6 nm of propane-1,1,1-d3 under high pressure and in the presence of NO or H2S was investigated. The results indicate that the main source of methyl radicals are the dissociation of propane and propyl radicals[Formula: see text]
Etude spectroscopique de l'aniline dans les solvants
Authors: Méallier P. , Berthelon A. , Pouyet B.
Published: May 2006

The effect of change of solvent on the positions and intensities of absorption bands of some aromatic amines between 200 and 400 nm has been examined. In particular, the behavior of the band at 280 nm has been studied.In hydroxylic solvents, this band is displaced towards shorter wavelengths, and the dipole moment in the excited state of the molecule is smaller than in the ground state. The opposite effects are found when nonhydroxylic solvents are used.The results show how the molecular structure is altered by charge transfer effects and can explain how different solvents affect photochemical oxidation processes.
Combinatorial Entropy of Mixing Molecules that Differ in Size and Shape. A Simple Approximation for Binary and Multicomponent Mixtures
Authors: Donohue Marc D. , Prausnitz John M.
Published: May 2006

For liquid solutions, the combinatorial entropy of mixing is commonly calculated using either (a) the ideal-solution model (suitable for mixtures of simple spherical molecules) or (b) the Flory lattice model (suitable for mixtures of chainlike molecules). Based on the lattice theories of Huggins, Staverman, Tompa, and Lichtenthaler for molecules of arbitrary size and shape, this work proposes an adhoc generalization of Flory's formula for the combinatorial entropy of mixing in binary and multicomponent solutions. The generalized Flory model yields results that are always intermediate between those obtained from (a) and (b). Parameters re quired for the calculations are found from molecular structure data (bond angles and distances). Illustrative calculations are given for the system carbon tetrachloride – octamethylcyclotetrasiloxane.
Substituent Effects on the Ionization Equilibria of 9-Aryl-9-fluorenols and 10-Aryl-10-hydroxyanthracen-9-ones
Authors: Toone Trevor W. , Lee-Ruff Edward , Hopkinson Alan C.
Published: May 2006

The title compounds were prepared and their basicities measured. In both systems the major part of the molecule is held planar, while an aryl group is free to rotate. This may interact with the positive charge but steric hindrance to the ortho hydrogens may be expected to oppose planarity. In these systems no evidence was found for a reduction of the normal σ+ value due to failure to achieve planarity. A formula is presented which gives the approximate degree of resemblance (α) of the transition state to the products and, in the case of the ionization of triarylmethanols, α is found to be linear with pKR+. It is suggested that this could resolve the apparent contradiction between the Hammett equation and the Hammond postulate.
Etude des spectres de vibration des dérivés monosubstitués en position 5 de l'isothiazole
Authors: Mille Gilbert , Poite Jean-Claude , Chouteau Jacques , Metzger Jacques
Published: May 2006

The i.r. absorption spectra in different physical states and the Raman spectra in the liquid or solid state of 5-monosubstituted isothiazole derivatives, C3NSH2Y (Y = CH3, CD3, Cl, Br, I) have been analyzed. An assignment of the fundamental modes of vibration of these molecules is given.
Oxidation of Dibenzo[a,e]fluoranthene by Osmium Tetroxide
Authors: Jacquignon P. , Perin-Roussel O. , Perin F. , Chalvet O. , Lhoste J. M. , Mathieu A. , Saperas B. , Viallet P. , Zajdela F.
Published: May 2006

Dibenzo[a,e]fluoranthene is treated by osmium tetroxide, the nature, structure, and configuration of the compound obtained (a trans dihydro diol) are defined taking into account the chemical, theoretical, and physicochemical arguments.
Investigation on the Favorable Formation of 5α-Cholestan-3α-ol and 5-Cholesten-3α-ol by Catalytic Hydrogenation
Authors: Ishige Masayoshi , Shiota Michio
Published: May 2006

Catalytic hydrogenation of 5α-cholestan-3-one was investigated to examine the factors influencing the selective formation of the axial 3α-ol and it has been found that the most satisfactory yield of 3α-ol is realized using Urushibara nickel A, the nickel catalyst treated by acid, in hydrocarbon solvents at lower temperatures under high pressure. Preparation of epicholestanol and epicholesterol by this method is described.
The Role of Excess Kinetic Energy in the Reactions of O(1D) Atoms
Authors: Overend Ralph , Paraskevopoulos George , Crawford Janice R. , Wiebe H. Alan
Published: May 2006

The effect of the excess kinetic energy of O(1D) atoms on their reactions with some gaseous compounds was investigated using two different experimental methods. O(1D) atoms with maximum excess kinetic energies of 41 ± 5 and 31 kcal/mol respectively, were produced by flash photolysis of N2O (1800–2300 Å) and by photolysis of N2O at 2139 Å, in the presence and absence of He which is a deactivator of kinetic energy. In the first method the competition between N2O and one of CO2, Xe, CO, and N2 for O(1D) atoms was measured and it was found that the relative rate constants [Formula: see text] and [Formula: see text] are not affected by the excess kinetic energy of the O(1D) atoms.In the second method the competition between neopentane and one of CO2, Xe, CO, and N2 for O(1D) atoms was measured. The results of the second study were not entirely conclusive. However, they also indicate no effect or at best only a very small effect of excess kinetic energy.
Reversible Inhibition of Carboxypeptidase A. IV. Inhibition of Specific Esterase Activity by Hippuric Acid and Related Species and other Amino Acid Derivatives and a Comparison with Substrate Inhibition
Authors: Bunting John W. , Myers Chester D.
Published: May 2006

The anions of each of the following carboxylic acids exhibit uncompetitive inhibition of the hydrolysis of O-hippuryl-L-3-phenyllactic acid by bovine carboxypeptidase A at pH 7.5, 25°, ionic strength 0.2: hippuric acid, p-chloro- and p-nitrohippuric acids, hippurylglycine, carbobenzoxyglycine, phenaceturic acid, N'-(3-phenylpropanoyl)glycine, benzoxyacetic acid, 3-benzoylpropanoic acid, and O-hippuryl-D-mandelic acid. In each case, this uncompetitive inhibition is consistent with the ordered binding of substrate and inhibitor to the enzyme; i.e. the inhibitor binds to E.S but not to the free enzyme. Evidence is presented for the binding site for uncompetitive inhibitors being the same as for inhibitory ester substrate molecules. Comparison of the specificities of uncompetitive inhibitors and esters which display substrate inhibition provides evidence for a critical conformational change which controls the binding of uncompetitive inhibitors and inhibitory substrate molecules.D-Phenylalanine, D-leucine, D-p-nitrophenylalanine, glycyl-L-tyrosine, glycyl-L-phenylalanine, and glycyl-L-leucine are competitive inhibitors of the enzymic hydrolysis of O-hippuryl-L-3-phenyllactic acid, whereas the N-chloroacetyl derivatives of L-tyrosine, L-phenylalanine, and L-leucine are noncompetitive inhibitors. For the above D-amino acids, glycyl dipeptides, and N-chloroacetyl amino acids, the phenylalanine derivative in each case is a considerably stronger inhibitor than the corresponding leucine derivative. This preference is similar to that observed for the binding of peptide substrates but the reverse of that observed for ester substrates and simple mono- and dicarboxylate ion inhibitors.The peptide substrates carbobenzoxyglycylglycyl-L-phenylalanine and N-chloroacetyl-L-phenylalanine are noncompetitive inhibitors of the enzymic hydrolysis of O-hippuryl-L-3-phenyllactic acid. This clearly demonstrates the presence of different ester and peptide binding sites in this enzyme, which is consistent with conclusions from recent studies in other laboratories.
Conformations of Bridged Diphenyls. VIII. Crystal Structure of 2-(2′,6′-Dinitrophenoxy)-t-butyIbenzene
Authors: Gurtu Kapil , Chandler W. David , Robertson Beverly E.
Published: May 2006

The crystal structure of 2-(2′,6′-dinitrophenoxy)-t-butylbenzene, C16HI5N2O5, has been determined by X-ray diffraction. The crystals are monoclinic, space group P21/c: a = 13.949(9), b = 9.652(6), c = 23.806(12) Å, β = 93.82(5), Z = 8. The integrated intensities of 6811 reflections were recorded with a four circle automated diffractometer at 20 °C; 3334 of these reflections were used in the refinement of the structure to a least-squares weighted residual of 0.057 and a traditional R factor of 0.057.The two crystallographically independent molecules both have the skew-t-butyl-distal conformation, suggesting that the steric effects of the two ortho-nitro groups play a greater role in determining the conformation than does conjugation with the bridging oxygen atom.
Some Reactions of 1-Lithio-2-phenyl-1,2-dihydropyridine. IV. Synthesis of β-Substituted Pyridines
Authors: Giam C. S. , Knaus E. E. , Lockhart R. A. , Keener I. G.
Published: May 2006

Alkylation of the ambident anion 1-lithio-2-phenyI-1,2-dihydropyridine (1a) has been investigated. A direct method for introducing an alkyl or arylalkyl group into the β-position of pyridine is described. Reaction of 1a with styrene oxide or ethylene oxide afforded 2-(2-phenyl-5-pyridyl)-1-phenylethanol (10) and 2-(2-phenyl-5-pyridyl)ethanol (11), respectively. With N-benzylideneaniline the unexpected 2-phenyl-5-benzylpyridine (7) was obtained. When 1a was allowed to react with perhalomethanes, conditions conducive to carbene formation, bis(6-phenyl-3-pyridyl)methane (12) and 6,6′-diphenyl-3,3′-dipyridyl (13) were obtained. Mechanisms for the formation of 7, 12, and 13 are discussed. Reactions of 1a with other electrophilic substrates are described.
Thione Photochemistry: The Peri Cyclization of some Polycyclic Aromatic Thiones
Authors: Cox A. , Kemp D. R. , Lapouyade R. , Mayo P. de , Joussot-Dubien J. , Bonneau R.
Published: May 2006

A number of polycyclic aromatic thiones have been prepared from the corresponding ketones. Several of the thiones in which there is a free peri position cyclize, on excitation in the π* ← n band, to give thiophene derivatives. The structures of these were proven by application of physical methods and by desulfurization to the corresponding benzyl derivatives. The formal hydrogen 1,3 migration involved was, in one case, shown to be intermolecular by the incorporation of deuterium, from deuterium oxide, during the irradiation. In the case of the α-naphthyl derivative, the mechanism of the reaction has been investigated and it has been concluded that the n,π* singlet is the responsible entity.
The Charge Transfer Photochemistry of the Hexaaquoiron(III) Ion, the Chloropentaaquoiron(III) Ion, and the µ-Dihydroxo Dimer Explored with tert-Butyl Alcohol Scavenging
Authors: Langford Cooper H. , Carey John H.
Published: May 2006

There have been several studies of the charge transfer photochemistry of aqueous Fe3+ but the complexity of hydrolytic equilibria and the requirement for scavengers to render the primary photochemical processes observable has left several issues moot as recent reports show. Using tert-butyl alcohol as a scavenger, it is shown that (at 35 °C), charge transfer irradiation at 254 nm of Fe(OH2)63+ gives free •OH with a quantum yield of 0.065, charge transfer irradiation of Fe(OH2)5Cl2+ at 350 nm gives free Cl• with a quantum yield of 0.093, and that as a result of the combined patterns of extinction coefficients and hydrolytic equilibria it is difficult to make Fe(OH2)5OH + the main absorbing species at either wavelength. The dihydroxo-bridged dimer gives only a small radical yield. The scavenger, tert-butyl alcohol, appears to react with •OH or Cl• to give •CH2—C(CH3)2OH which, on reaction with a second Fe(OH2)63+ gives HOCH2C(CH3)2OH.
The Kinetics of Quinoline Hydrodenitrogenation through Reaction Intermediate Products
Authors: Aboul-Gheit Ahmed Kadry
Published: May 2006

Under petroleum hydrotreating conditions and in the presence of a Co–M–alumina catalyst, quinoline is hydrodenitrogenated through a consecutive first order reaction involving a hydrogénation step followed by two hydrocracking steps. The first step is too fast to measure whereas the second step is the slowest. The ratio of the rate constants of the second to the third step ranges between 0.33 and 0.62 at reaction temperatures between 350 and 400 °C. The second step can be considered responsible for the relatively high activation energy and enthalpy values obtained for the overall reaction. The activation entropy obtained for the overall reaction is −38.2 e.u. mol−1, while the second and the third steps have values of −43.9 and −58.0 e.u. mol−1, respectively. These values indicate the progressive complexity of the steps involved in the reaction sequence as it proceeds towards ammonia production.
Chemistry of Transition Metals. V. Further Studies on the Mechanism of Reaction of n-Alkyl Chlorides with Metals of the First Transition Period
Authors: Egan Robert W. , Harrod John F.
Published: May 2006

The rate of reaction of n-propyl chloride on polycrystalline evaporated titanium films has been shown to follow a strictly half-order rate law in the pressure range 0.1–0.01 Torr at 220 °C. The reaction rate was not influenced by the product propene. Experiments using a mixture of 1-bromopropane and l-chloropropane-1-d1 gave no indication of halogen interchange on either titanium or chromium, thus excluding rapid, reversible dissociative adsorption of the carbon–halogen bond as an explanation of the half-order rate law.
Infrared Spectra of the Ammonium Ion in Crystals. I. Ammonium Hexachloroplatinate(IV) and Hexachlorotellurate(IV)
Authors: Oxton Ian A. , Knop Osvald , Falk Michael
Published: May 2006

Infrared spectra of polycrystalline (NH4)2PtCl6 and (NH4)2TeCl6 at various degrees of deuteration were recorded between 4000 and 1000 cm−1 at 30 and −165 °C. The stretching and bending vibrations of NH4+, NH3D+, NH2D2+, NHD3+, and ND4+ ions in these two compounds were systematically examined. The observed fundamentals were unambiguously assigned by analogy with the vibrations of the partially deuterated methanes. The spectrum of isotopically dilute NH3D+ confirms the existence of only one crystallographically distinct type of ammonium ion in the structure, on sites of Td symmetry. Vibrational coupling of neighboring ammonium ions was not detected.
Carbon-13 Nuclear Magnetic Resonance Spectra of Some Dendroketose and Other Furanose Derivatives
Authors: Vyas Dolatrai M. , Jarrell Harold C. , Szarek Walter A.
Published: May 2006

The carbon-13 n.m.r. spectra of derivatives of the branched-chain sugars apiose and dendroketose, and of other furanose sugars, are reported. The study has permitted assignment of the configuration at the branching carbon atom and at the anomeric center in the dendroketose derivatives.
The Use of Deuterium Magnetic Resonance in the Determination of the Structure and Location of the Anilinium Ion in an Aqueous Anisotropic Surfactant Solution
Authors: Diehl Peter , Tracey Alan S.
Published: May 2006

Anisotropic soap solutions containing the anilinium ion have been studied by n.m.r. techniques. The partially averaged proton–proton dipole couplings were used to obtain the relative positions of the hydrogen nuclei of the phenyl ring. Deuterium quadrupole splittings from the deuterium enriched ion provided information concerning the quadrupole coupling constant, QD, the asymmetry parameter, η, and the angles that the C—D bonds make with the coordinate systems axes. Quadrupole splittings from the deuterium enriched decylsulfate simultaneously with those from the anilinium ion established that the C2 axis of the ion on an average lies parallel to the decylsulfate chain axis and is ordered to a similar extent. It is concluded that the aromatic ring is incorporated into the superstructure of the soap solution and that the —NH3+ group protrudes into the electrical double layer where it interacts with the oppositely charged decylsulfate and with water.
Arene Derivatives of Bis(trichlorogermanium)tetracarbonylruthenium(II)
Authors: Pomeroy Roland K. , Graham William A. G.
Published: May 2006

Arenes react with trans-Ru(CO)4(GeCl3)2 at 150 °C or higher to form the very stable complexes (η-arene)Ru(CO)(GeCl3)2 (arene = benzene, toluene, o-, m-, and p-xylene, mesitylene). The reactions may proceed via the more reactive cis-isomer, as suggested by a study of the reaction of benzene with trans-Ru(CO)4(SiCl3)2 at 80 °C to form (η-C6H6)Ru(CO)-(SiCl3)2. Benzene is displaced from (η-C6H6)Ru(CO)(GeCl3)2 by CO or mesitylene forming trans-Ru(CO)4(GeCl3)2 and (η-mesitylene)Ru(CO)(GeCl3)2, respectively.
Studies in Solvolysis. Part VII. The Neutral Hydrolysis of Methyl Perchlorate
Authors: Robertson Ross Elmore , Annesa Adrianna , Scott John Marshall William
Published: May 2006

The temperature dependence of the rate of hydrolysis of methyl perchlorate has been measured and the entropy (ΔS≠), enthalpy (ΔH≠), and heat capacity (ΔCp≠) of activation calculated. The measurements confirm that the perchlorate ion is superior to all other leaving groups in water. The isotope effect related to the hydrolysis of methyl-d3 perchlorate has been measured at three temperatures and shown to be inverse. The thermodynamic parameters and the isotope effect were examined with respect to the mechanism of substitution at a primary carbon atom.
CNDO/2 Studies on Ion Solvation by Methanol
Authors: Salomon Mark
Published: May 2006

CNDO/2 calculations are presented for the solvation of the ions H+, Li+, Na+, F−, and Cl− by methanol. The results are compared with previous calculations for solvation by water and with the experimental data of Kebarle. Predicted stabilization energies are grossly overestimated but differences in stabilization energies agree well with the experimental data.
Volumes and Heat Capacities of Dimethylsulfoxide, Acetone, and Acetamide in Water and of some Electrolytes in these Mixed Aqueous Solvents
Authors: Kiyohara Osamu , Perron Gèrald , Desnoyers Jacques E.
Published: May 2006

The densities and volumetric specific heats of binary mixtures of dimethylsulfoxide (DMSO), acetone (ACT), and acetamide (ACM) in water were measured at 25 °C with a flow densimeter and a flow microcalorimeter. The same properties were also determined for ternary mixtures of 0.1 m LiCl, NaCl, Me4NBr, and Bu4NBr in ACT–water and DMSO–water mixtures, and volumes for 0.1 m Bu4NBr in ACM–water and urea–water mixtures. The derived apparent molal volumes and heat capacities of nonelectrolytes in water and the transfer functions of the electrolytes from water to the mixed solvents suggest that, contrary to urea, the present non-electrolytes are slightly hydrophobic but, with the possible exception of ACT, their overall influence on water structure has practically no influence on the various solute–solute interactions.
A Differential Spectroscopic Technique for Obtaining the Spectra of Chemisorbed Molecules
Authors: Moskovits M. , Hope C. J. , Jantzi B.
Published: May 2006

A technique for recording the first derivative with respect to wavelength of the infrared spectrum of a substance is described. Its use allows one to detect with enhanced sensitivity a weak spectrum superimposed upon a strong, featureless background such as is encountered in the specular reflectance spectra of monolayers adsorbed on metal surfaces. The method is illustrated by the infrared spectrum of CO adsorbed on deposited copper.
Some Reactions of trans-Hydridochlorobis(tricyclohexylphosphine)nickel(II), trans-Ni(Cl)(H)[P(C6H11)3]2
Authors: Clark Howard C. , Shaver Alan
Published: May 2006

Some reactions of the title compound with several ligands, including olefins and acetylenes have been conducted and the new complexes trans-[NiH{P(C6H11)3}2L]BF4, L = methylpyridine or acetonitrile have been isolated. Although the bulky phosphine apparently hinders reaction sterically, with hexafluoro-2-butyne a product is obtained which is tentatively characterized as Ni(CF3C≡CCF3)3P(C6H11)3. This compound is thought to contain the seven-membered ring nickelahexakis(trifluoromethane)cyclohepta-cis,cis,cis-triene. Pyrolysis of this compound yields hexakis(trifluoromethyl)benzene. A reaction of the nickel hydride also occurs with carbon monoxide in the presence of TlBF4 to give Ni(CO)3P(C6H11)3 and [P(H)(C6H11)3]BF4. This reaction can be considered to result from the reductive elimination of [P(H)(C6H11)3]Cl.
Polymerization in situ Accompanying Field Desorption Mass Spectrometry
Authors: Wood Gordon Walter , Wade Donna Lee
Published: May 2006

Field desorption mass spectrometry of hydroxycarboxylic acids results in ions corresponding to condensation polymerization with water loss. The phenomenon is particularly marked with 3-hydroxypropanoic acid where at high anode temperatures the base peak corresponds to 6M – 5H2O and ions up to 13M – 12H2O are observed.
An ESCA Investigation of some Halogeno(methyl)-Silane and -Germane Series
Authors: Drake John E. , Riddle Chris , Coatsworth L.
Published: May 2006

Core-level binding energies of all atoms are reported for two series of compounds; MenMCl4−n and Me3MX (n = 0 → 4, M = Si or Ge, X = F, Cl, Br, I and (for M = Ge) CN, N3, and NCS ). Binding energy shifts are discussed using a 'whole-molecule' approach and are correlated with estimated atomic charges derived from an electronegativity-equalization procedure. Carbon 1s binding energies are also correlated to 13C n.m.r. chemical shifts.
Spectres de masse d'hydrazino-2 benzo- et naphtothiazoles et d'hydrazones des méthyl-3 benzo- et naphtothiazolinones-2
Authors: Richer Jean-Claude , Lapointe Philippe , Beljean Martine , Pays Michel
Published: May 2006

Electron impact mass spectra are reported for the hydrazones of 3-methyl-2-benzothiazolinone (1), of 4-, 5-, 6-, and 7-chloro-3-methylbenzo-2-thiazolinones (2, 3, 4, and 5) and of 3-methyl-naphtho[2,1-d]-2-thiazolinone (6), as well as for 2-hydrazinobenzothiazole (7), for 4-, 5-, 6-, and 7-chloro-2-hydrazinobenzothiazoles (8, 9, 10, and 11) and for 2-hydrazinonaphtho[2,1-d]thiazole (12). The results obtained in the two series are compared. The 2-hydrazone and 3-methyl-benzo-2-thiazolinone and its derivatives all form a base peak corresponding to the molecular ion; fragmentation proceeds mainly by successive losses of·NH2, HCN, HCN, and then CS. Initial losses of N2H2, NH·, and NH3 are minor fragmentation routes.In the case of 2-hydrazinobenzothiazole and its derivatives, the base peak is still that of the molecular ion; however, the relative proportions of the various fragment ions vary with the position of sampling probe inside the apparatus. Thus it is concluded that the observed mass spectrum is that of a mixture of the possible hydrazone-hydrazine tautomers. The principal fragmentations involve the initial loss of NH3 (leading to a stabilized ion), of NH2· (probably from the hydrazone form), and of N2H2.(Journal Translation)
Preparation and Properties of Carboxylic, Monothiocarboxylic, Dithiocarboxylic, and Sulfinic Acid Derivatives of Trithiane, Tetrathiocane, and Pentathiecane
Authors: Peach Michael E. , Schmidt Max , Weissflog Eckhard
Published: May 2006

The monoacids derived from trithiane, tetrathiocane, and pentathiecane, C3H5S3X (X = CO2H, COSH, CS2H), C4H7S4X (X = CO2H, CS2H), and C5H9S5X (X = CO2H, CS2H) and the lithium salts C3H5S3SO2Li, C4H7S4SO2Li, and C5H9S5SO2Li have been prepared and their reactions studied. The corresponding esters C3H5S3CO2R (R = CH3, C2H5, n-C3H7, i-C3H7n-C4H9, n-C5H11), C3H5S3COSCH3, C4H7S4CO2R (R = CH3, C2H5) and the ammonium salts, C3H5S3CO2NH4, C3H5S3CS2NH4, C3H5S3CS2N(n-Bu)4, C4H7S4CO2NH4, (C4H7S4CO2)2(Me2NHCH2)2, and C5H9S5CO2NH4 have been isolated. The reactions of the acid anion with various metal ions have been investigated. Nuclear magnetic resonance, mass, and infrared spectroscopic data of some of the products are reported.
The 1,3,5-Trinitrobenzene–Phenoxide σ-Complex. Ambident Phenoxide Ion in SNAr Systems
Authors: Buncel Erwin , Jończyk Andrzej , Webb John G. K.
Published: May 2006

1,3,5-Trinitrobenzene reacts with potassium phenoxide in dimethyl sulfoxide solution to yield a σ-complex in which bonding has occurred between the para carbon of the phenoxy moiety and an unsubstituted carbon of the nitroaromatic substrate. A minor proportion of ortho adduct is also obtained. When the reaction is performed in DMSO–MeOH (80:20, v/v) one obtains initially the methoxide adduct of TNB which is then smoothly transformed into the phenoxide adduct. The latter is stable to dilute mineral acid, unlike the former; formation of a σ-complex involving bonding between the phenoxy oxygen and a carbon of TNB is thereby excluded. The reaction represents the first instance of phenoxide ion acting as an ambident nucleophile towards aromatic carbon. The implication of this finding on the course of related SNAr reactions is discussed on the basis of kinetic and thermodynamic control of product formation.
SCF MO Study Of Benzo[d]aceheptylene
Authors: DasGupta Archana , DasGupta Nanda K.
Published: May 2006

The molecule benzo[d]aceheptylene has been studied using the method of Dewar and Harget, and Yamaguchi etal. Heats of atomization, bond energies, reactivity, bond length, and π* ← π transitions are reported and aromaticity of the molecule is discussed.
Single Crystal Electron Spin Resonance Of Low Spin Co(II) And Of Cu(II) Schiff Base Complexes
Authors: Malatesta V. , McGarvey B. R.
Published: May 2006

Single crystal e.s.r. studies have been done on N,N′-ethylenebis(o-aminobenzylideniminato)nickel(II) and N,N′-ethylenebis(benzoylacetoniminato)nickel(II) doped with the corresponding Co(II) and Cu(II) complexes. It is shown for the cobalt(II) complexes that the unpaired electron is in a dyz orbital and that the d orbitals are arranged [Formula: see text]in order of increasing energy with the [Formula: see text]and dyz orbitals being close together. The large energy separation between the dxz and dyz orbitals which is found in the cobalt(II) complexes is not observed in the corresponding copper(II) complexes. 14N hyperfine constants were measured for both copper(II) complexes.
Magnetic and Spectral Studies on Cobalt(II) and Copper(II) Salts of Methylsulfuric, Trifluoromethylsulfuric, and Paratolylsulfuric Acids
Authors: Arduini Anita L. , Garnett Maureen , Thompson Robert C. , Wong Tony C. T.
Published: May 2006

The compounds Co(CF3SO3)2, Cu(CF3SO3)2, Co(CH3SO3)2, Cu(CH3SO3)2, Co(p-CH3C6H4SO3)2, and Cu(p-CH3C6H4SO3)2 have been prepared and infrared spectra, electronic spectra, and magnetic susceptibility studies are reported. Electronic spectral and magnetic studies have also been made on Cu(FSO3)2 and previously published data on Co(FSO3)2 are reexamined here. The studies indicate that in all salts the metal ions are hexacoordinated by oxygen atoms provided by anions acting as tridentate bridging ligands. The MO6 skeleton is significantly distorted from regular octahedral geometry for all salts with the possible exceptions of Co(FSO3)2, Co(p-CH3C6H4SO3)2, and Co(CH3SO3)2. Values of the spin–orbit coupling constants for the salts, as estimated from the magnetic studies, decrease with increasing anion basicity, suggesting a correlation between basicity and the degree of covalent character in the metal–anion bonds. In the case of the cobalt salts the interelectron repulsion parameter B also seems to decrease with increasing anion basicity.
Angiotensin II Type 1 Receptor Antagonist Candesartan as an Angiogenic Inhibitor in a Xenograft Model of Bladder Cancer
Authors: Kosugi Michio , Miyajima Akira , Kikuchi Eiji , Horiguchi Yutaka , Murai Masaru
Published: May 2006

Purpose: There have been several studies on the antitumor activity of angiotensin II type 1 receptor (AT1R) antagonists. In this study, we evaluated the efficacy of the AT1R antagonist candesartan in bladder cancer.

Experimental Design: For the study in vitro, human bladder cancer cells (KU-19-19) were cultured with or without angiotensin II and candesartan. Various cytokines and cell viability were analyzed. For the study in vivo, a tumor xenograft model was prepared in nude mice using KU-19-19 cells. Mice were given candesartan daily by oral gavage. Microvessel density, expression of vascular endothelial growth factor (VEGF), and apoptosis were assessed.

Results: Candesartan did not induce direct toxicity in KU-19-19 cells, but VEGF and interleukin-8 were significantly lower in candesartan-treated cells (2.55 ± 0.25 and 6.58 ± 0.48 pg/103 cells) than in the angiotensin II–treated control cells (3.16 ± 0.42 and 7.91 ± 0.69 pg/103 cells). In mice, candesartan both at doses of 2 and 10 mg/kg/d significantly suppressed tumor growth in mice (35.4% and 33.5% reduction in tumor volume). Microvessel density was significantly decreased by candesartan (9.8 ± 2.8 per field) compared with the control group (17.6 ± 6.0 per field), and VEGF expression was significantly suppressed by this AT1R antagonist. However, candesartan did not induce apoptosis of cancer cells in the tumor.

Conclusions: Specific blockade of AT1R prevented bladder tumor growth by inhibiting angiogenesis. However, its antitumor effect was not due to direct toxicity. Because AT1R antagonists are widely used to treat hypertension, and a 2 mg/kg/d dose level of candesartan is clinically achievable, this AT1R antagonist could also be used to treat bladder cancer.
Tumor-Specific CD8+ T Cell Reactivity in the Sentinel Lymph Node of GM-CSF–Treated Stage I Melanoma Patients is Associated with High Myeloid Dendritic Cell Content
Authors: Vuylsteke Ronald J.C.L.M. , Molenkamp Barbara G. , van Leeuwen Paul A.M. , Meijer Sybren , Wijnands Pepijn G.J.T.B. , Haanen John B.A.G. , Scheper Rik J. , de Gruijl Tanja D.
Published: May 2006

Purpose: Impaired immune functions in the sentinel lymph node (SLN) may facilitate early metastatic events during melanoma development. Local potentiation of tumor-specific T cell reactivity may be a valuable adjuvant treatment option.

Experimental Design: We examined the effect of locally administered granulocyte/macrophage-colony stimulating factor (GM-CSF) on the frequency of tumor-specific CD8+ T cells in the SLN and blood of patients with stage I melanoma. Twelve patients were randomly assigned to preoperative local administration of either recombinant human GM-CSF or NaCl 0.9%. CD8+ T cells from SLN and peripheral blood were tested for reactivity in an IFNγ ELISPOT assay against the full-length MART-1 antigen and a number of HLA-A1, HLA-A2, and HLA-A3–restricted epitopes derived from a range of melanoma-associated antigens.

Results: Melanoma-specific CD8+ T cell response rates in the SLN were one of six for the control group and four of six for the GM-CSF-administered group. Only one patient had detectable tumor-specific CD8+ T cells in the blood, but at lower frequencies than in the SLN. All patients with detectable tumor-specific CD8+ T cells had a percentage of CD1a+ SLN-dendritic cells (DC) above the median (i.e., 0.33%). This association between above median CD1a+ SLN-DC frequencies and tumor antigen–specific CD8+ T cell reactivity was significant in a two-sided Fisher's exact test (P = 0.015).

Conclusions: Locally primed antitumor T cell responses in the SLN are detectable as early as stage I of melanoma development and may be enhanced by GM-CSF-induced increases in SLN-DC frequencies.
A Phase I/II Trial Testing Immunization of Hepatocellular Carcinoma Patients with Dendritic Cells Pulsed with Four α-Fetoprotein Peptides
Authors: Butterfield Lisa H. , Ribas Antoni , Dissette Vivian B. , Lee Yohan , Yang Jin Quan , De la Rocha Pilar , Duran Sonia D. , Hernandez Jackie , Seja Elisabeth , Potter Douglas M. , McBride William H. , Finn Richard , Glaspy John A. , Economou James S.
Published: May 2006

α-Fetoprotein (AFP) is a self protein expressed by fetal liver at high levels, but is transcriptionally repressed at birth. AFP is up-regulated in hepatocellular carcinomas, and patients with active disease could have plasma levels as high as 1 mg/mL. We previously identified four immunodominant HLA-A*0201-restricted peptides [hAFP137-145 (PLFQVPEPV), hAFP158-166 (FMNKFIYEI), hAFP325-334 (GLSPNLNRFL), and hAFP542-550 (GVALQTMKQ)] derived from human AFP that could stimulate specific T cell responses in healthy donor peripheral blood lymphocytes in vitro. We conducted a phase I/II clinical trial in which HLA-A*0201 patients with AFP-positive hepatocellular carcinoma were immunized with three biweekly intradermal vaccinations of the four AFP peptides pulsed onto autologous dendritic cells (DC). DCs were prepared from adherent peripheral blood mononuclear cells cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4 for 7 days. Sixteen subjects were enrolled and 10 were treated. Peripheral blood lymphocytes were isolated from these patients before, during, and after AFP peptide/DC immunization and were tested ex vivo with MHC tetramer and IFNγ ELISPOT analysis. Six of 10 subjects expanded statistically significant levels of AFP-specific T cells postvaccine to at least one peptide by MHC tetramer. Also, 6 of 10 subjects increased IFNγ producing AFP-specific T cell responses to at least one of the peptides postvaccination, by ELISPOT. We conclude that the human T cell repertoire is capable of responding to the AFP self antigen after the administration of AFP peptide-pulsed DC even in an environment of high circulating levels of this oncofetal antigen.
Infringement of Copyright and Trade Marks in Electronic Commerce: A Kuwaiti and Comparative Approach
Authors:   Al-kandari
Published: May 2006

No Abstract
Interest under the UAE Law and as applied by the Courts of Abu Dhabi
Authors:   Tamimi
Published: May 2006

No Abstract
Moving in from the Margins? Turkey in Europe
Authors: Keyder Caglar
Published: May 2006

Turkey's historical intimacy with Europe has always spelled ambivalence between inclusion and exclusion. Religious difference was an issue from the start, but this did not stop the Ottomans from recruiting Byzantine princes and Venetian grandees to serve their new state. The sultans in those early centuries claimed the Byzantine mantle and saw their realm as the New Rome, a universal empire in the making. Indeed, European attitudes betrayed an acceptance of these claims as well; it was only after the 16th century, and especially with the Reformation, that the Ottomans emerged as an irrecoverable other.