Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond. 3-Substituted N,N,2,4,6-Pentamethylbenzamides

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Title:Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond. 3-Substituted N,N,2,4,6-Pentamethylbenzamides
Creators:
Přibylová, Eva
Holík, Miroslav
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 64, 1, pp. 44-60
Uncontrolled Keywords:NMR line shape analysis, Dynamic NMR spectroscopy, Hindered rotation, Axial chirality, Thermodynamic parameters, Rate constants

Abstract

Three programs for the <sup>1</sup>H NMR line shape analysis of systems with unequally populated sites have been tested in order to get highly accurate rate constants of the hindered rotation about a single bond using four published criteria. The programs differ in the number of optimized parameters. As test compounds, 3-(adamantan-1-carbonyl)-<i>N,N</i>,2,4,6-pentamethylbenzamide (<strong>1</strong>) and 3-(2-dimethylpropanoyl)-<i>N,N</i>,2,4,6-pentamethylbenzamide (<strong>2</strong>) were prepared. It was found that a supermodified simplex method with only six parameters optimized in one step gives the most accurate values of the rate constants. Consequently, the calculated thermodynamic parameters <i>E</i><sub>a</sub>, ∆<i>H</i><sup>≠</sup> and ∆<i>S</i><sup>≠</sup> lie in relatively narrow confidence intervals. <p>

Title:Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond. 3-Substituted N,N,2,4,6-Pentamethylbenzamides
Creators:
Přibylová, Eva
Holík, Miroslav
Uncontrolled Keywords:NMR line shape analysis, Dynamic NMR spectroscopy, Hindered rotation, Axial chirality, Thermodynamic parameters, Rate constants
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:64
Number:1
Page Range:pp. 44-60
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19990044UNSPECIFIED
ID Code:1455
Item Type:Article
Deposited On:06 Feb 2009 17:09
Last Modified:06 Feb 2009 16:09

Citation

Přibylová, Eva; Holík, Miroslav (1999) Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond. 3-Substituted N,N,2,4,6-Pentamethylbenzamides. Collection of Czechoslovak Chemical Communications, 64 (1). pp. 44-60. ISSN 0010-0765

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