## Abstract The variation of the ^15^N chemical shifts with substitution for a series of 1‐aryl‐3,3‐dialkyltriazenes is decribed. Good correlations were found between the relative chemical shifts at all three nitrogen sites and the electronic properties, as measured by the substituent coefficient,
NMR studies of hindered rotation and thermal decomposition of novel 1-aryl-3,3-dialkyltriazenes
✍ Scribed by Th. Lippert; A. Wokaun; J. Dauth; O. Nuyken
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 725 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
1‐Aryl‐3,3‐dialkyltriazenes have been synthesized by coupling the corresponding diazonium salts of substituted aniline derivatives with dialkylamines. The thermostability of these compounds was investigated by differential scanning calorimetry; activation energies of 240–280 kJ mol^−1^ were determined for the thermal decomposition. The hindered rotation of the dialkylamino group was studied by ^1^H NMR exchange measurements. Both experiments are interpreted in terms of an involvement of a 1,3‐dipolar structure of the NNN functional group. The influence of substituents, both on the aromatic ring and at the amino group, on the kinetic and activation parameters is investigated; results are analysed on the basis of mesomeric and steric effects on the dipolar charge distribution in the molecule.
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