| Abstrakt: |
On a basis of comparison of Raman and IR absorption spectra, as well as measurements of intensities and degrees of depolarization of Raman lines, pulsation (breathing) vibrations of the ethylenimine ring -?sN?in a series of N-substituted ethylenimines are identified. Alkyl substituents increase?sN?as compared with ethylenimine, probably because of change in the hydridization of the electron clouds of the nitrogen due to steric causes. The high values of?sN?for substituents capable of conjugation effects, is in accord with the hypothesis that the lone electron pair of the nitrogen participates in conjugation. Furthermore, when N enters into the composition of a 3-membered ring, the lone pair exhibits diminished capacity for delocalization. The intensity of the Raman line?sN? of N-phenylethylenimine is anomalously high, and the cause of this requires explaining. UV spectra are given. |
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