Fluorescence of 8-Phenylamino-1-naphthalene-ammonium-sulfonate in solvents of different polarity

The solvatochromic fluorescence properties of 8-(phenylamino)-1-naphthalene-ammoniumsulfonate (1) were investigated in 22 pure solvents of rising polarity. The measurements of both Stokes shifts and intensities discriminated between protic and aprotic solvents. Fairly good linear correlation plots of the dependence could be obtained on neglection of the values of tert.-butanol, DMF and DMSO.