Zusammenfassung
Activation parameters for the interconversion of conformers IA and IB of neopentylbenzylnitrosamine and of rotamers IIA and IIB of N,2,4,6-tetramethyl-N-benzylbenzamide were determined by two techniques: Equilibration of pure IB (or IIA, respectively) and subsequent measurement of 1H-NMR line shapes with the same sample. Ea- and k0-values obtained by the two methods agree well within error ...
Zusammenfassung
Activation parameters for the interconversion of conformers IA and IB of neopentylbenzylnitrosamine and of rotamers IIA and IIB of N,2,4,6-tetramethyl-N-benzylbenzamide were determined by two techniques: Equilibration of pure IB (or IIA, respectively) and subsequent measurement of 1H-NMR line shapes with the same sample. Ea- and k0-values obtained by the two methods agree well within error limits, thus confirming the accuracy of rate determinations using NMR line shapes. Chemical shifts Δν, line widths bE, and equilibrium constants K were extrapolated to those temperatures at which they could not be measured directly. Line shape parameters were used for the evaluation of spectra. This method is shown to be preferable to the complete line shape analysis if the line broadening by field inhomogeneities is not taken into account by a convolution.
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