SPECTRAL CHARACTERISTICS OF 4-AMINODIPHENYL ETHER IN DIFFERENT SOLVENTS AND AT VARIOUS PH VALUES

The solvatochromic shifts are found to be mainly due to the interactio n of solvents with the amino group of 4-aminodiphenyl ether (ADPE). Th ere is an increase in Stokes' shift with the increase in polarity and hydrogen bonding ability of solvents. The abnormal red shift in the fl uorescence spectrum on protonation of ADPE is neither due to the amino group becoming more basic nor due to large solvent relaxation in aque ous solution but is due to monocation-solvent exciplex formation. The monocation of ADPE in cyclohexane followed the normal blue shift in th e fluorescence spectrum. Contrary to other aromatic amines, ADPE does not undergo proton-induced quenching.