F. Pollinger et al., PHOTOINDUCED ELECTRON-TRANSFER IN CYCLOPHANE-BRIDGED PORPHYRIN-QUINONE MOLECULES - A SUBPICOSECOND TRANSIENT ABSORPTION STUDY, Berichte der Bunsengesellschaft fur Physikalische Chemie, 100(12), 1996, pp. 2076-2080
Citations number
29
Categorie Soggetti
Chemistry Physical
Journal title
Berichte der Bunsengesellschaft fur Physikalische Chemie
Photoinduced charge separation and recombination in a series of cyclop
hane-bridged porphyrin-quinone systems (PQ) in toluene solution have b
een investigated by means of sub-ps time-resolved absorption spectrosc
opy. Temporal profiles and transient spectra of the porphyrin cation (
P+) show the photoinduced formation and decay of the charge-separated
state P(+)Q(-). The rate of charge recombination in these systems (P()Q(-) --> PQ) is investigated as a function of the reaction free energ
y Delta G in the range (-Delta G) = 1.54-1.98 eV, which is in the so-c
alled inverted region of electron transfer. Combining values for charg
e separation and recombination the dependence of the electron transfer
rate on Delta G fully covers the normal and inverted regions ((-Delta
G) = (-)0.02-1.98 eV) with the rate varying over more than three orde
rs of magnitude (approximate to 2 . 10(9) - 5 . 10(12) s(-1)).