Theoretical study on the mechanism of ester hydrolysis in micellar catalysis using model systems

1994 ◽  
pp. 2053 ◽  
Author(s):  
Kenzi Hori ◽  
Akio Kamimura ◽  
Junko Kimoto ◽  
Sachiko Gotoh ◽  
Yasuji Ihara
Keyword(s):  
Theoretical Study ◽  
Ester Hydrolysis ◽  
Micellar Catalysis ◽  
Model Systems

The vibrational spectroscopy of the coordinated azide anion; a theoretical study

2016 ◽  
Vol 18 (1) ◽  
pp. 414-425 ◽  
Author(s):  
Eliano Diana ◽  
Karl Gatterer ◽  
Sidney F. A. Kettle
Keyword(s):  
Group Theory ◽  
Vibrational Spectroscopy ◽  
Vibrational Spectra ◽  
Theoretical Study ◽  
Model Systems ◽  
Related Model ◽  
Azide Anion ◽  
Charge Distributions

DFT has been used to model azide complexes and related model systems, in order to provide an understanding of azide vibrational spectra. The spectra are controlled by the charge distributions and the metal involved. This means that a group theory-based approach will seldom enable an interpretation, even though the azide groups are commonly vibrationally coupled.

Experimental and Theoretical Study of the First Vanadocene(IV) Complexes of α-Amino Acids Prepared from Vanadocene Dichloride

2004 ◽  
Vol 69 (4) ◽  
pp. 811-821 ◽  
Author(s):  
Jaromír Vinklárek ◽  
Hana Paláčková ◽  
Jan Honzíček
Keyword(s):  
Amino Acids ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Model Systems ◽  
Amino Groups ◽  
Aqueous Methanol ◽  
Functional Theory ◽  
Elemental Analyses ◽  
Vanadocene Dichloride

The first bioinorganic vanadocene(IV) complexes of α-amino acids ([Cp2V(aa)]Cl, Cp = η5-C5H5, aa = glycine, L-alanine, L-valine) were prepared by reaction of vanadocene dichloride ([Cp2VCl2]) and α-amino acids in aqueous methanol. Analogous cationic complexes with PF6- counterions were obtained by metathetical reactions of the chloride precursors with KPF6. These compounds are of great interest as model systems for the vanadocene moiety binding to proteins. All complexes have been characterized by elemental analyses and IR, Raman and EPR spectroscopies. On the basis of EPR spectra, a chelate in all the studied complexes was proposed, formed by the carboxylato and amino groups. This structure has also been confirmed by density functional theory (DFT) calculations.

Theoretical study of the polymer molecules (TeO2)n as model systems for the local structure in TeO2 glass

2004 ◽  
Vol 345-346 ◽  
pp. 734-737 ◽  
Author(s):  
O. Noguera ◽  
M. Smirnov ◽  
A.P. Mirgorodsky ◽  
T. Merle-Méjean ◽  
P. Thomas ◽  
...  
Keyword(s):  
Local Structure ◽  
Theoretical Study ◽  
Model Systems ◽  
Polymer Molecules

The thermal isomerization of bicyclic oxazines into epoxyepimines. A preliminary theoretical study

1990 ◽  
Vol 68 (9) ◽  
pp. 1625-1628 ◽  
Author(s):  
Michel Sana ◽  
Georges Leroy ◽  
Jean-Luc Vaerman ◽  
Heinz Gunter Viehe
Keyword(s):  
Substituent Effect ◽  
Theoretical Study ◽  
Thermal Isomerization ◽  
Model Systems ◽  
Rate Determining Step ◽  
Bond Homolysis

The thermal isomerization of bicyclic oxazines 1 to epoxyepimines 2 depends on the N-substituent. BDE calculations on model systems agree with the mechanistic picture. The rate-determining step in N—O bond homolysis is facilitated by N-vinyl substituents. Keywords: oxazines, BDE, NO bond, substituent effect.

A theoretical study of conformational deuterium isotope effects and bond dissociation energies of diastereotopic hydrogens

1991 ◽  
Vol 69 (9) ◽  
pp. 1408-1412 ◽  
Author(s):  
Saul Wolfe ◽  
Chan-Kyung Kim
Keyword(s):  
Theoretical Study ◽  
Isotope Effects ◽  
Model Systems ◽  
Bond Dissociation Energies ◽  
Model Compounds ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Deuterium Isotope Effects ◽  
Derivatives Of ◽  
Good Agreement

In the conformations that correspond to the C6-X1-C2-X3-C4 moieties of 1,3-dioxane, 1,3-dithiane, and cyclohexane in their chair conformations, the model systems CH2(OH)2, CH2(SH)2, and gauche-butane contain "axial" and "equatorial" hydrogens. The vibrational frequencies of the diastereomeric monodeuterated CHD derivatives of these model compounds have been computed ab initio at the 6-31G*//6-31G* level of theory, scaled by 0.9, and used to calculate the conformational deuterium isotope effects in these systems, as well as the stretching and bending components of these isotope effects. The results are in very good agreement with the experimental observations and with some of the interpretations given by Anet for the six-membered rings. Using an equation suggested by McKean, the scaled isolated stretching frequencies have been used to predict the bond dissociation energies of the diastereotopic hydrogens of these molecules. The results suggest that the preference for radical abstraction of the axial C2 hydrogen in a 1,3-dioxane will be diminished in cyclohexane, and reversed in a 1,3-dithiane. Key words: stereochemistry, isotope effects, bond dissociation energies.

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