INTRAMOLECULAR DONOR-ACCEPTOR SYSTEMS. Part 8. Solvent and substituent effects on the fluorescence emission of 6-N-methyl-N-phenylamino-2-naphthalenesulfon-N,N-dimethylamides

Article abstract of DOI:10.1016/0022-2860(82)85259-9

The dual fluorescence (emissions from S_1,np and S_1,ct states) of N-phenylaminonaphthalenesulfonate (ANS) systems is briefly reviewed.The 6-N-methyl-N-phenylamino-2-naphthalenesulfon-N,N-dimethylamides also exhibit dual fluorescence, as shown by plots of emission energy and Φ_F against the sovent polarity parameter, E_T(30).The solvent polarities, for which appearance of S_1,ct emission marks the occurence of an intramolecular electron transfer (i.e.t.) process, are appreciably lower than those of the corresponding sulfonates.The fluorescence of the dimethylamides exhibits a high sensitivity to substituent change, the apparent Hammett ρ value being ca. -13 for unsubstituted dimethylamide and -33 for N-methyl-substituted dimethylamide.The N,N-dimethylamides are particularly suitable for the investigation of the rates and mechanisms of intramolecular electron-transfer processes by picosecond and nanosecond pulse techniques.