Effect of substituents on the spectroscopic properties of all-trans-1,6-diphenyl-1,3,5-hexatriene

An extensive spectroscopic study of two derivatives of the all-trans-1,6-diphenyl-1,3,5-hexatriene (DPH) has been conducted. The one derivative carries, at the para position of one of the phenyl rings of the parent molecule, the electron donating -N-(CH3)(2) group, while the other carries at the same position the electron withdrawing -NO2 substituent. The absorption-fluorescence spectra, quantum yields, lifetimes and steady state fluorescence anisotropies of these derivatives, were studied in various solvents, at different temperatures and at different viscosities. The findings are presented and discussed along with the exceptional fluorescence probing properties of these two particular derivatives. For comparative purposes, the main spectroscopic properties of the parent molecule are also included. (C) 1998 Elsevier Science B.V.