Abstract:

Intramolecular energy transfer and electron transfer of porphyrin-phthalocyanine heterodimers, linked by oxygen atom or piperazine in different solvents were investigated by fluorescence spectroscopy. The energy transfer and electron transfer efficiency were calculated. It has been found that energy transfer occurred in competition with electron transfer process depending on the polarity of the solvents. In polar solvents, electron transfer prevails while the energy transfer is favored in nonpolar solvents. The driving force(△GET0)of the electron transfer reaction in different solvents was estimated using Rehm-Weller equation. The results indicated that the conformations of the heterodimers as well as the ability of the solvent to stablize the charge-seperated state affect the photophysical process greatly. Good correlations of φEnT and φET with solvent polarity f have been obtained.

Key words: Solvent effect, Dyad, Energy transfer, Electron transfer