Energy transfer processes in electronically coupled porphyrin hetero-dyads connected at the beta position.
Energy transfer in a series of hetero-dyads of zinc porphyrin and free-base porphyrin connected at the beta position by pi conjugated bridges has been determined. The dyads have been characterized and compared with the homo dyads, excellent models for the donor and the acceptor porphyrins in the electronically conjugated system. The homo dyads provide reliable parameters for the determination of the energy transfer rate calculated according to the Förster theory. This model was inadequate to account for the experimental findings and an electron exchange mechanism was shown to contribute. A favorable coplanar arrangement of the bridge and the tetrapyrroles facilitates the energy transfer process, which displays a very low distance dependence and an efficiency >98%.
Ventura
Barbara
B
Istituto per la Sintesi Organica e la Fotoreattività (ISOF), CNR, Via P. Gobetti 101, 40129 Bologna, Italy.
Barigelletti
Francesco
F
Lodato
Fabio
F
Officer
David L
DL
Flamigni
Lucia
L