The i.r. spectra of the title compounds have been recorded in the region 3500-3150 cm-1 in CH2Cl2 and CH2Cl2/DMSO solutions. In the region of the free NH stretching vibrations, the spectra show an envelope of bands which have been deconvoluted in order to separate the two ν (NH) contributions. The peak due to ν (NH) of N-3 decreases on increasing the DMSO concentration, thus indicating that this hydrogen is mainly involved in the interaction with DMSO in accordance with its higher acidity. The influence of the exo-chalcogen atoms on these frequencies has been discussed. A good empirical correlation has been found between the ν (NH)s and the charge densities (calculated by CNDO/S) on the hydrogen and nitrogen atoms.
NH stretching vibrations of 5,5-dimethylimidazolidines with O, S, or Se atoms at C(2) and C(4).
ISAIA, FRANCESCO;
1985-01-01
Abstract
The i.r. spectra of the title compounds have been recorded in the region 3500-3150 cm-1 in CH2Cl2 and CH2Cl2/DMSO solutions. In the region of the free NH stretching vibrations, the spectra show an envelope of bands which have been deconvoluted in order to separate the two ν (NH) contributions. The peak due to ν (NH) of N-3 decreases on increasing the DMSO concentration, thus indicating that this hydrogen is mainly involved in the interaction with DMSO in accordance with its higher acidity. The influence of the exo-chalcogen atoms on these frequencies has been discussed. A good empirical correlation has been found between the ν (NH)s and the charge densities (calculated by CNDO/S) on the hydrogen and nitrogen atoms.
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