Imines infrared frequencies

The tertiary enamines, in contrast to the secondary derivatives, cannot exhibit enamine-imine tautomerism. As the free bases, they exist only in the vinylamino form. Their physico-chemical properties are in agreement with this structure, especially the spectral properties. The bands due to the stretching frequency of the carbon-carbon double bond in their infrared spectra1-25-27 (situated at 1630-1660 cm-1 according to the nature of the substituents) occur at somewhat lower frequencies, but their intensities are greatly increased in comparison to those of simple olefins because of conjugation with the free electron pair on the nitrogen atom. Indications of cis-trans isomerism... 

The gas-phase Raman spectra of trimethylene imine and trimethylene imine-N-tf were studied later by Carreira et al.90 The transitions in the low-frequency region for trimethylene imine-N-d are shown in Fig. 4.21, and Table 4.13 summarizes the assignments of the transitions observed in the far infrared and Raman spectra. The... 

Dihydropyrrole is a pseudo-four-membered ring molecule. Its structural relationship to trimethylene imine is the same as that of 2,5-dihydrofuran to trimethylene oxide. Again, both the parent and N-d compounds were studied. Figure 4.22 shows the far infrared spectrum of the light compound reported by Carreira and Lord89 The low-frequency Raman spectrum was reported later by Carreira et al.9°). Transitions with both Av = 1 and Av = 2 were observed. Table 4.14 summarizes the... 

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