The Vacuum Ultraviolet Absorption Spectra of Aniline and Some of Its N-Derivatives

Abstract The vacuum ultraviolet absorption spectra of anilne, N-methylaniline, N-ethylaniline, N,N-dimethylaniline, N,N-diethylaniline and N-n-butylaniline have been measured in the vapor phase by a recording vacuum ultraviolet spectrophotometer, with which the absorption measurements have been extended down to 1500 Å. Some new bands have been found in the vacuum ultraviolet region, and in total five π→π* transtion bands with molar extinction coefficients larger than 1500 have been observed commonly for the anilines. In order to clarify the nature of these bands, a theoretical treatment has been made by considering the configuration interaction among the ground, locally excited and charge-transfer configrations. An excellent agreement has been obtained between the experimental and the calculated result. It has been concluded the the anilines studied here exhibit intramolecular charge-transfer bands characteristic if the electron trasfer interaction between the substituent and benzene ring.