Journal of Physical Chemistry A, Vol.108, No.3, 455-467, 2004
pi-Conjugated electroactive oligomers: Energy and electron transducing systems
Suitably difunctionalized oligomers have been used to synthesize a series of novel, soluble, and strongly fluorescent C-60-conjugated oligomer triads through 1,3-dipolar cycloaddition reactions. The nature of the oligomeric components have been modified to tailor (i) the absorption wavelength of the chromophore and (ii) the oxidation potential of the oligomeric donor moiety. The resulting triads were examined by electrochemical and photophysical techniques. Both singlet-singlet energy transfer and intramolecular electron transfer were found to take place and to compete with each other in the overall deactivation of the photoexcited chromophores. Strong electronic couplings between the donor and acceptor moieties not only affect the ground-state spectra, which exhibit marked red shifts, but, more importantly, give rise to ultrafast electron and energy transfer reactions. In terms of stabilizing the product and enhancing the yield of charge separation, comparison with previously reported analogues containing only a single fullerene unit (i.e., dyad) shows that particular benefits were noted by attaching two fullerene cores (i.e., triad) to the oligomeric structure.