Spectroscopic studies of four new derivatives of benzamide

Four new benzamide derivatives i.e. N-(4'-methyl)phenylbenzamide (I); N,N'-methyl(4'-methyl)phenylbenzamide (II); N-benzylbenzamide (III) and N-(4'-nitro)phenylbenzamide (IV) have been spectroscoply studied in hydrocarbon and weak polar solvents. The fluorescence studies show that some of those derivatives (I and II) in the excited state undergo conformation changes caused by proton transfer reaction or twisted intramolecular charge-transfer processes. Making use from the determined lambda(max) values of the absorption and fluorescence spectra the dipole moment of the molecules in the S-1 state has been evaluated for I, II and III. (C) 1999 Elsevier Science S.A. All rights reserved.