Fluorescence properties of 3,6-dihydroxyphthalimide-triethylamine system in dichloroethane

摘要

Fluorescence emission of the efficient dye laser compound 3,6-dihydroxyphthalimide in dichloroethane solution has been investigated as a function of the concentration of the added strong proton acceptor triethylamine by both steady-state and time-resolved (time-correlated single-photon counting) techniques. Complex decay behavior has been observed. The dominating portion of the emission of the molecules follows the Stern-Volmer quenching. The other part of emission, clearly observed at high concentrations of triethylamine, is assigned to hydrogen-bonded complexes. The fully ionized 3,6-dihydroxyphthalimide is detected as a product of the irreversible excited-state proton-transfer reaction. In solution of neat triethylamine an excited ion pair is formed upon excitation of the hydrogen-bonded 3,6-dihydroxyphthalimide molecules.