The 13C N.M.R. spectra of a series of 5,5-dimethyl 2,4-dichalcogeno substituted imidazolidines are reported. The 13C chemical shifts are assigned by means of a CNDO/S calculation. On the whole the shielding effect of the di-homochalcogeno atoms on C-2 and C-4 increases in the order Se ≤ S O while for the di-hetero atoms no regular trends have been found. On the contrary the resonance of C-5 inside the ring moves downfield keeping one chalcogen atom constant and substituting the oxygen with sulphur and selenium.
N.M.R. spectra of having O, S, or Se atoms in 2, 4.
ISAIA, FRANCESCO;
1985-01-01
Abstract
The 13C N.M.R. spectra of a series of 5,5-dimethyl 2,4-dichalcogeno substituted imidazolidines are reported. The 13C chemical shifts are assigned by means of a CNDO/S calculation. On the whole the shielding effect of the di-homochalcogeno atoms on C-2 and C-4 increases in the order Se ≤ S O while for the di-hetero atoms no regular trends have been found. On the contrary the resonance of C-5 inside the ring moves downfield keeping one chalcogen atom constant and substituting the oxygen with sulphur and selenium.
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