Photoinduced Electron Transfer in Amino Acid Assemblies

Published

Journal Article

The preparation and photophysical characterization of a series of redox-active lysines and related model compounds based on polypyridyl ruthenium complexes are described. Donor-chromophore-acceptor triad 1, [PTZpn-Lys(RuIIb2m)2+-NH-prPQ2+] (PF6−)4 (see below), was prepared by assembly of a modified ruthenium bipyridyl chromophore (RuIIb2m, where b = 2,2′-bipyridine, m = 4′-methyl-2,2′-bipyridyl-4′-carbonyl), an electron donor (phenothiazine, PTZ), and an electron acceptor (paraquat, PQ2+) on a lysine (Lys) scaffold utilizing amide bonds. This derivatized amino acid exhibited efficient (>95%) quenching of the ruthenium metal-to-ligand charge-transfer (MLCT) excited state upon irradiation with a 420-nm laser pulse in CH3CN. The resulting redox-separated state, [(PTZpn·+)-Lys(RuII,b2m)2+-NH-(prPQ·+)], stored 1.17 eV and lived for 108 ns (k = 9.26 × 106 s−1) as observed by transient absorption spectroscopy. Also studied was a series of related model systems that included model chromophores, simple chromophore-quencher dyads linked by amide bonds, and chromophore-quencher dyads based on lysine. An account of the kinetic behavior of these systems including triad 1 and a discussion of factors that influence the lifetime of the redox-separated states, their efficiency of formation, and their energy storage ability are presented. © 1993, American Chemical Society. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Mecklenburg, SL; Peek, BM; Schoonover, JR; McCafferty, DG; Wall, CG; Erickson, BW; Meyer, TJ

Published Date

  • June 1, 1993

Published In

Volume / Issue

  • 115 / 13

Start / End Page

  • 5479 - 5495

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/ja00066a017

Citation Source

  • Scopus