Spectroscopic investigations on butadiene derivatives. 1H, 13C and 15N NMR studies on the π-electron distribution and intramolecular mobility of aminobuta-1,3-dienes
✍ Scribed by Manfred Michalik; Thomas Freier; Kerstin Zahn; Klaus Peseke
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 333 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
The 1H, 13C and 15N NMR spectra of a series of 5-alkylthio-3-aryl-2-cyano-5-dialkylaminopenta-2,4-dienenitriles (4 and 5) with di †erent amino and aryl substituents were recorded. The NMR chemical shifts are correlated with electronic e †ects of the substituents on the donor side of the butadiene system and also the para-phenyl substituents X. Dynamic 1H and 13C NMR measurements showed rotational processes about the C-2,C-3, C-3,C-4, C-4,C-5 and C-5,N bonds in 4 and 5, the kinetic and thermodynamic parameters of which were determined by lineshape analysis. The assignment of the lineshape alterations was made on the basis of signal intensities and separations and from the inÑuence of the donor substituents, the phenyl substituents X and the solvents on the energy barriers.