Charge-transfer complexes. Part XI. Quenching of anthracene fluorescence by anions

Abstract

The group of simple inorganic anions known to exhibit charge-transfer-to-solvent (C.T.T.S.) absorption bands in solution, have also been found to be effective in the quenching of anthracence fluorescence. Correlation of quenching constants with both the redox potential, when known, and with the energy of the C.T.T.S. absorption band maximum, supports a mechanism involving electron transfer. The data is tentatively interpreted in terms of an excited state charge-transfer complex (‘exciplex’) formation, although no emission band due to an exciplex was detected. No detectable change occurred in the absorption band of anthracene on the addition of the quencher.