Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone

[img]PDF - Authorized users only
Language: English
70Kb
Title:Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone
Creators:
Přibylová, Eva
Holík, Miroslav
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 63, 7, pp. 955-966
Uncontrolled Keywords:Thermal racemization, HPLC/polarimetry, NMR line shape analysis, Dynamic NMR spectroscopy, Thermodynamic parameters, Rate constants

Abstract

Four programs for the <sup>1</sup>H NMR line shape analysis: two commercial - Winkubo (Bruker) and DNMR5 (QCPE 165) and two written in our laboratory - Newton (in Microsoft Excel) and Simtex (in Matlab) have been tested in order to get highly accurate rate constants of the hindered rotation about a single bond. For this purpose four testing criteria were used, two of them were also developed by us. As supplementary determinations the rate constants obtained for the coalescence temperature and for the thermal racemization of chromatographically separated enantiomers were used which fitted well the temperature dependence of the rate constants determined by the line shape analysis. As a test compound adamantan-1-yl 3-bromo-2,4,6-trimethylphenyl ketone was prepared and studied. It was shown that supermodified simplex method used in our algorithm (Simtex), though time consuming, gives the most accurate values of the rate constants and consequently the calculated thermodynamic parameters <i>E<sub>a</sub></i>, ∆<i>H</i><sup>≠</sup>, and ∆<i>S</i><sup>≠</sup> lay in relatively narrow confidence intervals.

Title:Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone
Creators:
Přibylová, Eva
Holík, Miroslav
Uncontrolled Keywords:Thermal racemization, HPLC/polarimetry, NMR line shape analysis, Dynamic NMR spectroscopy, 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:63
Number:7
Page Range:pp. 955-966
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19980955UNSPECIFIED
ID Code:1354
Item Type:Article
Deposited On:06 Feb 2009 17:08
Last Modified:06 Feb 2009 16:08

Citation

Přibylová, Eva; Holík, Miroslav (1998) Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone. Collection of Czechoslovak Chemical Communications, 63 (7). pp. 955-966. ISSN 0010-0765

Repository Staff Only: item control page