Photochemical energy conversion in a helical oligoproline assembly.
A general method is described for constructing a helical oligoproline assembly having a spatially ordered array of functional sites protruding from a proline-II helix. Three different redox-active carboxylic acids were coupled to the side chain of cis-4-amino-L-proline. These redox modules were incorporated through solid-phase peptide synthesis into a 13-residue helical oligoproline assembly bearing in linear array a phenothiazine electron donor, a tris(bipyridine)ruthenium(II) chromophore, and an anthraquinone electron acceptor. Upon transient 460-nm irradiation in acetonitrile, this peptide triad formed with 53% efficiency an excited state containing a phenothiazine radical cation and an anthraquinone radical anion. This light-induced redox-separated state had a lifetime of 175 ns and stored 1.65 eV of energy.
McCafferty
D G
DG
Department of Chemistry, University of North Carolina, Chapel Hill 27599, USA.
Friesen
D A
DA
Danielson
E
E
Wall
C G
CG
Saderholm
M J
MJ
Erickson
B W
BW
Meyer
T J
TJ
D008958:Models, Molecular; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D010777:Photochemistry; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis; D013997:Time Factors
D010455:Peptides; C011083:polyproline