Dm. Guldi et al., EXCITATION OF C-60, SOLUBILIZED IN WATER BY TRITON X-100 AND GAMMA-CYCLODEXTRIN, AND SUBSEQUENT CHARGE SEPARATION VIA REDUCTIVE QUENCHING, Chemical physics letters, 223(5-6), 1994, pp. 511-516
The excitation of C60 incorporated in triton X-100 micelles has been s
tudied by laser flash photolysis. Reductive quenching of triplet-excit
ed C-3(60) by diazabicyclooctane (DABCO) has been established in the m
icellar assembly, in aqueous solution of the fullerene embedded in gam
ma-cyclodextrin, in alcohols and non-polar toluene. In aqueous media p
otassium hexacyanoferrate (II) and potassium iodide have been employed
in the reductive quenching process as well. The C60-. radical anion i
n all investigations has been characterized by its IR absorption. The
formation and the half-life of C60-. have been shown to be strongly de
pendent on the polarity of the environment. By utilizing DABCO as a qu
encher a half-life of 440 mus has been observed in the micellar assemb
ly, while the respective values in propan-2-ol and butan-1-ol are 110
and 98 mus, respectively. In aqueous solution the radical anion gamma-
CD/C60-. decays with a half-life of 59 mus and, in contrast, in the no
n-polar toluene no formation of any C60-. could be detected. The resul
ts are consistent with a charge-separated C-3(60)-quencher contact pai
r.