The quenching of excited aromatic esters by triethylamine (original) (raw)

The interaction of excited aromatic esters with tertiary aliphatic amines, triethylamine (TEA) and diazobicyclo 12.2.23 octane has been investigated. In non-polar solvents the fluorescence quenching that is observed is accompanied in most cases by an exciplex emission when TEA is the quencher, whereas the radical anions of the esters are detected in polar solvents. The large dipole moments found for the exciplexes (9-16 debye) and the correlation of the bimolecular rate constant k, with the half-wave potential of the excited esters and the ionization potentials of the amines show that a charge transfer mechanism is operative in these systems.