Abstract:

Intramolecular energy-transfer and electron-transfer of porphyrin-phthalocyanine heterodimer, linked by piperazine, were investigated by absorption and fluorescencc spectroscopy. The efficiency of energy transfer(ФEnT) and electron transfer (ФET) were calculated. The results indicate that: In benzene, the main photophysical process is excited singlet-singlet energy transfer, while in DMF photoinduced electron transfer predominant. The ФET of this heterodimer in DMF is bigger than that of porphyrin-phthalocyanine heterodimers linked by oxygen or flexible chains. This may be ascribed to the "boat-form" conformation of piperazine, According to the CPK molecular model, porphyrin and phthalocyanine are held together in a face to face way, and the center to center distance between two macrorings is about 3.56 Å . It is suggested that conformational changes from "chair form" to "boat form" occurred subsequent to optical excitation in DMF.

Key words: Piperazine, Heterodimer, Intramolecular energy transfer, Photoinduced electron transfer