190579-87-4Relevant articles and documents
Reversed substituent effect on C=O stretching vibrations in hydantoin derivatives
Uscumlic, Gordana S.,Drmanic, Sasa Z.,Krstic, Vera V.
, p. 193 - 195 (2007/10/03)
The infrared spectra have been recorded for thirteen 3-substituted-5,5-dimethylhydantoins in the region of fundamental C=O stretching vibrations in dichloromethane. The frequencies of symmetric and asymmetric C=O stretching vibrations are correlated with Taft's ?* substituent constants. When the electron-releasing substituents are in position-3 in the hydantoin ring the stretching frequency increases with the increase in the electronegativity. However, the effect of electron-withdrawing substituents appears to be quite opposite, i.e. the carbonyl stretching vibrations are decreased. The correlations with extended Hammett equation Qx = α?I + β?R + h and with Swain-Lupton equation pij = fF + rR + h give the results which according to Jaffe can be considered as poor. The correlation obtained from Hammett ?p constants furnish satisfacory results except the substituents with a wide range of polarity. The mechanism of the transmission of substituent effects in hydantoin systems is discussed considering the results of above mentioned observations.