Deactivation of pyrene exciplexes in W/O microemulsions made with benzylhexadecyldimethylammonium chloride (BHDC)

M.A. ALTAMIRANO; C.D. BORSARELLI; J.J. COSA; C.M. PREVITALI

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 1997 vol. 102 p. 223 - 229

1010-6030

The photophysical properties of exciplexes formed between pyrene and N,N'-dimethylaniline (DMA) or p-dicyanobenzene (DCB) were studied in benzene and benzylhexadecyldimethylammonium chloride-benzene-water microemulsions. The fluorescence of the exciplexes in benzene solution was strongly quenched by the addition of benzylhexadecyldimethylammonium chloride. Laser flash photolysis experiments were carried out in reversed micellar solutions. The transient absorption spectra showed the presence of the pyrene triplet state in all cases. For the pyrene-DMA system, the absorption of the pyrene radical anion was observed; however, the corresponding radical cation was not observed in the pyrene-DCB system. These results are discussed in terms of hydrophobic and electrostatic effects at the surfactant-water interface of the microemulsion.