MECHANISMS OF EXCITED-STATE QUENCHING BY AROMATIC SULFOXIDES

Aromatic sulfoxides quench singlet excited states of sensitizers whose singlet energies render energy transfer unlikely as a mechanism. Well over 50 rate constants for singlet quenching of various sensitizers b y a series sulfoxides have been obtained, as have estimates of the red ox potentials for the series of sulfoxides. These data strongly sugges t that the mechanism for quenching involves electron transfer and/or e xciplex formation. Charge (electron) transfer is from the sensitizer t o the sulfoxide.