Singlet—singlet intramolecular energy and electron transfer in covalently-linked porphyrin—phthalocyanine heterodimers

Abstract

Intramolecular transfer processes in porphyrin—phthalocyanine heterodimers covalently linked by an oxygen atom (restricted conformation) and/or by a flexible chain of variable length were investigated. Fluorescence spectroscopy shows that singlet—singlet energy transfer from the porphyrin to the phthalocyanine moiety occurs. From fluorescence decay studies, it is concluded that the heterodimers exist in solution in different non-equilibrating conformations. The effects of the chain length and mutual orientation of the chromophore subunits in the heterodimers on the intramolecular energy and electron transfer efficiencies are discussed.