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128 results on '"Édouard, C."'

54. Identification of the Epitope for the Epidermal Growth Factor Receptor-specific Monoclonal Antibody 806 Reveals That It Preferentially Recognizes an Untethered Form of the Receptor

Author

Johns, Terrance G., Adams, Timothy E., Cochran, Jennifer R., Hall, Nathan E, Hoyne, Peter A., Olsen, Mark J., Kim, Yong-Sung, Rothacker, Julie, Nice, Edouard C., Walker, Francesca, Ritter, Gerd, Jungbluth, Achim A., Old, Lloyd J., Ward, Colin W., Burgess, Antony W., Wittrup, K. Dane, and Scott, Andrew M.

Published
2004
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70. Core and valence electrons in atom-by-atom descriptions of molecules

Author

Vincenzo Barone, Sándor Fliszár, and Édouard C. Vauthier

Subjects
Crystallography, Valence (chemistry), Core electron, Chemistry, Molecule, Ionic bonding, Electron, Valence electron, Elementary charge, Ion
Abstract

The core-valence electron partitioning in molecules is adequately described by the energy formulas E k v = ( V k − V ne, k c + V k cv )/ γ k v for the valence region of atom k in a molecule and E k ion = ( V ne, k c − V k cv )/ γ k c for the k th ionic core left after removal of the valence electronic charge, where V k and V ne, k c are, respectively, the total potential energy involving center k and the core nuclear-electronic potential energy of its N k c core electrons. V k cv denotes the interaction between N k c and the electronic and nuclear charges found outside the core region k . Properly selected γ k v and γ k c parameters, treated as constants, lead to valence-region energies in good agreement with those deduced from the total molecular energies E and the equation E v = E − ∑ k E k ion . The point-charge-potential model for V k cv , embodied in V k cv = − N k c [( V k − V ne, k c )/ Z k ], improves the accuracy of the results. These formulas are best suited for atom-by-atom (or bond-by-bond) descriptions of molecules because E k v is expressed solely in terms of the appropriate electrostatic potentials at the individual nuclei and does not depend on any particular mode of partitioning a molecule into atomic subunits.

Published
2000
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73. X-ALPHA LOCAL SPIN-DENSITY CALCULATIONS OF THE 1-1 HYDROGEN-BONDED COMPLEXES FORMED BY WATER, AMMONIA, AND HYDROGEN-FLUORIDE

Author

Vincenzo Barone, Sándor Fliszár, Camilla Minichino, Édouard C. Vauthier, Vauthier, Ec, Barone, Vincenzo, Minichino, C, and Fliszar, S.

Subjects
Hydrogen, Hydrogen bond, Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Hydrogen fluoride, Bond-dissociation energy, Catalysis, Dissociation (chemistry), chemistry.chemical_compound, Ammonia, Hydrofluoric acid, chemistry, Physical chemistry, Spin density
Abstract

The dissociation energies of the 1:1 hydrogen-bonded complexes formed by NH3, H2O, and HF were computed in the LCGTO-Xα local spin density approximation using extended basis sets. Attention was given to the appropriate selection of α. The order of stability of the various complexes reflects well their acid–base properties, in general agreement with experimental data and refined post Hartree–Fock computations. Keywords: hydrogen bonds, Xα method, local spin density method.

Published
1990

76. Charge distributions and chemical effects. XXXVIII. Correlations between nuclear magnetic resonance shifts and electronic charges of nitrogen atoms

Author

Marie-Thérèse Béraldin, Sándor Fliszár, Édouard C. Vauthier, and Michel Comeau

Subjects
education.field_of_study, Organic Chemistry, Population, chemistry.chemical_element, Resonance, Charge (physics), General Chemistry, Electron, Oxygen, Nitrogen, Catalysis, Chemical effects, Nuclear magnetic resonance, chemistry, education, Carbon
Abstract

Correlations between nuclear magnetic resonance shifts and atomic charges of nitrogen in selected alkylamines, nitroalkanes, isonitriles, and azines consistently follow the general trends observed for carbon and oxygen nuclei. In azines, any increase in total electronic population on nitrogen, resulting from a gain in π charge prevailing over a concurrent loss of σ electrons, is accompanied by an upfield resonance shift—as found for aromatic and ethylenic carbon and carbonyl oxygen atoms. On the other hand, any gain in total charge dictated by that of σ populations translates into a downfield 15N shift, which is the trend exhibited by alkylamines, nitroalkanes, and isonitriles—a situation encountered earlier with sp3-hybridized carbon, carbonyl carbon, and dialkyl ether oxygen atoms.

Published
1985
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77. Charge distributions and chemical effects. XXVI. Relationships between nuclear magnetic resonance shifts and atomic charges for 17O nuclei in ethers and carbonyl compounds

Author

Édouard C. Vauthier, Sándor Fliszár, and Marie-Thérèse Béraldin

Subjects
Chemical effects, Range (particle radiation), Oxygen atom, Nuclear magnetic resonance, Chemistry, Organic Chemistry, Atomic charge, Charge (physics), General Chemistry, Nuclear magnetic resonance spectroscopy, Electron, Elementary charge, Catalysis
Abstract

The 17O nuclear magnetic resonance shifts of dialkylethers are linearly related to the electron populations on the oxygen atoms, in a range covering L ~ 130 ppm, showing that any increase of electronic charge at the oxygen atom is accompanied by a downfield nmr shift. The opposite trend is observed for the oxygen atoms of ketones and aldehydes.

Published
1982
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78. MP2 calculation of nuclear magnetic shielding constants involving gauge-invariant bases

Author

S. Odiot, Édouard C. Vauthier, Sándor Fliszár, and Michel Comeau

Subjects
Chemistry, Organic Chemistry, Gaussian orbital, General Chemistry, Nuclear magnetic resonance spectroscopy, Diatomic molecule, Catalysis, Paramagnetism, Nuclear magnetic resonance, Atomic orbital, Electromagnetic shielding, Diamagnetism, Atomic physics, Basis set
Abstract

Dia- and paramagnetic shielding constants of HF, NH3, N2, H2O, and CO were calculated in the 4-31G, 4-31G*, and 6-31G** bases, using gauge-invariant atomic orbitals. Correlation effects were evaluated by 2nd-order perturbation theory: while the diamagnetic contributions are virtually unaffected by correlation, the paramagnetic parts (σρ) are modified by ~10 ppm in the 6-31G** basis. With or without correlation, calculated σρ values differ significantly from results obtained from measured spin-rotation constants. However, improvements in the basis set descriptions and inclusion of correlation yield chemical shift values for 15N and 17O converging toward their experimental counterparts obtained from conventional nuclear magnetic resonance spectroscopy.

Published
1988
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79. Nuclear magnetic shielding calculations in the finite perturbation method involving GIAO's at the INDO level and London's approximation. II. Carbon-13 and nitrogen-15

Author

S. Odiot, F. Tonnard, Édouard C. Vauthier, and Sándor Fliszár

Subjects
Paramagnetism, chemistry, Computational chemistry, Organic Chemistry, Electromagnetic shielding, Carbon-13, chemistry.chemical_element, General Chemistry, Atomic physics, Nitrogen, Perturbation method, Catalysis
Abstract

Magnetic shielding constants, calculated for C-13 and N-15 nuclei in the finite perturbation method using INDO and London's approximations, are analyzed in terms of mono-, di-, and tricentric contributions, thus permitting an assessment of the relative importance of local vs. nonlocal contributions. For both C-13 and N-15, it appears that the changes in total shielding are almost entirely dictated by those of the local paramagnetic contribution, i.e., [Formula: see text].

Published
1983
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