Photoinduced electron transfer within porphyrin-containing poly(amide) dendrimers

[GRAPHICS] The synthesis and photophysical characterization of a series of free base p orphyrin containing polyamide dendrimers terminated with anthraquinone grou ps (FbP-Ga-AQ(n), a = 1-3, n = 12, 36, 108) are described. Substantial quen ching (58-75%) of the porphyrin fluorescence of FbP-Ga-AQ(n) is observed wh en compared to the analogous ethyl terminated dendrimers (FbP-Ga-Et-n) in s teady state fluorescence experiments and is attributed to intramolecular el ectron transfer. Time resolved fluorescence experiments were fit to 2-3 exp onentials, indicating multiple orientations for electron transfer, consiste nt with the flexible nature of these dendrimers.