Triplet and singlet energy transfer in carotene-porphyrin dyads: role of the linkage bonds.

Abstract

A series of carotenoporphyrin dyad molecules in which the carotenoid is covalently linked to a tetraarylporphyrin at the ortho, meta, or para position of a meso aromatic ring has been prepared, and the molecules have been studied using steady-state and transient fluorescence emission, transient absorption, and 1 H NMR methods. Triplet-triplet energy transfer from the porphyrin moiety to the carotenoid has been observed, as has singlet-singlet energy transfer from the carotenoid polyene to the porphyrin