P118
Photoinduced Electron Transfer Reactions Between Some Dimethyl Substituted
Phenols and 2-Nitrofluorene at Liquid Nitrogen Temperature
Subrata Sinha
Dept. of Spectroscopy
Indian Association for the Cultivation of Science
Steady state and time-resolved measurements reveal the nature of different
non-radiative transitions from the photoexcited donors (3,5-dimethylphenol,
2,6-dimethylphenol, 3,5-dimethylanisole, 2,5-dimethylanisole) in presence
of the acceptor 2-nitrofluorene in ethanol rigid glassy matrix at liquid
nitrogen temperature (77 K). Large negative values (-1.42 to -2.03 eV) of
driving energy indicate the occurrence of highly exothermic electron transfer
(ET) reactions in the singlet state, while relatively lower values (-0.17 to
-0.70 eV) of driving energy suggest moderately exothermic ET reactions in
the triplet state. From the computed value of destabilization energy (0.26
eV), it seems dipole rotations may not be fully eliminated at low temperature.
Apart from ET, Forster's type singlet-singlet energy transfer and Dexter's
type triplet-triplet energy transfer processes seem to be involved in the
fluorescence and phosphorescence quenching phenomena, respectively, of the
present donors in presence of the acceptor 2-nitrofluorene.
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