Intermolecular Fluorescence Quenching of Substituted Naphthalene Derivatives Induced by Charge Transfer Processes

Abstract

AbstractThe Stern‐Volmer quenching constants of substituted naphthalene derivatives were measured with different quenchers in cyclohexane and methanol as solvents. From the quenching constants and the decay time of the excited singlet state (measured with the oxygen quenching method) the absolute reaction rate constants (k5) of the bimolecular quenching reaction are determined. The k5‐values (table 5) are low when emitter and quencher are both acceptors or both donors, but the k5‐values are high when the emitter is acceptor and the quencher donor or vice versa. Since complete electron transfer is excluded on energetical grounds it is concluded that the primary step for fluorescence quenching in these systems involves charge transfer interaction.