Electron transfer in Me-blocked heterodimeric [alpha], [gamma]-peptide nanotubular donor-acceptor hybrids

Brea, R.J., Castedo, L., Granja, J.R., Herranz, M.A., Sanchez, L., Martin, N., Seitz, W. and Guldi, D.M.

PNAS 104(13), 5291-5294 (2007)

NDRL 4715

Bio-inspired cyclopeptidic heterodimers built on [beta]-sheet-like hydrogen-bonding networks and bearing photoactive and electroactive chromophores on the outer surface have been prepared. Different cross-strand pairwise relationships between the side chains of the cyclic [alpha],[gamma]-peptides afford the heterodimers as three nonequivalent dimeric species. Steady-state and time-resolved spectroscopies clearly show an electron transfer process from [pi]-extended tetrathiafulvalene, covalently attached to one of the cyclopeptides, to photoexcited [60]fullerene, located on the complementary cyclopeptide. The charge-separated state was stabilized for up to 1 [mu] before recombining and repopulating the ground state. Our current example shows that cyclopeptidic templates can be successfully used to form light-harvesting/lightconverting hybrid ensembles with a distinctive organization of donor and acceptor units able to act as efficient artificial photosystems.