Chemically modified dansyl probes: A fluorescent diagnostic for ion and proton detection in solution and in polymers

The fluorescence emission intensity of the dansyl group is significantly diminished upon appending an ethyldimethylamino group to the N1 nitrogen substituent. Addition of acids and metal ions (i.e., Zn2+) to solutions of trimethylethylenediamine naphthalene sulfonamide (trinsyl) 2 produces a > 25-fold increase in fluorescence intensity. Trinsyl probe 2 has been used as a diagnostic for the diffusion of protons and metal ions in a network polymer as well as an optical reporter for the glass transition temperature.