| Abstract | Photoinduced electron-transfer processes between fullerenes C60/C70 and disubstituted-naphthalenes have been studied by laser flash
photolysis. Quantum yields (?T
et) and rate constants (ket) of electron transfer from naphthalenes to the excited triplet states of C60 (3C?60)
and C70 (3C?70) have been determined by observing the transient absorption bands in the wide wavelength VIS/NIR regions. The observed
?T
et and ket values depend significantly on the nature and position of the substituents. The ket values are seen to correlate well with the
free energy changes (Get) for the electron transfer reactions on the basis of Rehm–Weller relation. Addition of pyridine (Py) enhanced
significantly the rates and efficiencies of photoinduced electron transfer process of dihydroxy-naphthalenes (DHN). However, the effect
of Py in the dimethoxy-naphthalenes (DMN) is far less than that of DHN. In the presence of octylviologen (OV2+), electron-mediation
occurs from C60•? to OV2+ to generate OV•+. © 2001 Elsevier Science B.V. All rights reserved. |