SOLVENT-TUNED INTRAMOLECULAR CHARGE-RECOMBINATION RATES IN A CONJUGATED DONOR-ACCEPTOR MOLECULE

The nonradiative charge-recombination rates from the charge-transfer state of a new conjugated donor-acceptor molecule (p-cyano-p′-methylthiodiphenylacetylene) can be tuned over almost an order of magnitude by varying the polarity of the solvent. These measurements of intramolecular recombination show a turnover of rates as a function of emission energy, consistent with the "normal" and "inverted" behavior of Marcus theory. Steady-state spectra and time-resolved measurements allow us to quantitatively compare thermal and optical electron-transfer rates as a function of driving force and demonstrate their correspondence. © 1990 American Chemical Society.