Dynamics and efficiency of photoinduced charge transport in DNA

Toward the elusive molecular wire

Frederick D. Lewis, Michael R Wasielewski

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Experimental investigations of photoinduced charge transport in synthetic DNA capped hairpins possessing electron acceptor and donor stilbene chromophores at either end have established the mechanism, dynamics, and efficiency of charge transport in DNA. The mechanism for charge transport in repeating A-T base pairs (A-tracts) was found to change from single-step superexchange at short distances to multistep incoherent hole hopping at longer distances. The rate constants for base-to-base hole hopping in longer A- and G-tract sequences are 1.2 × 109 s-1 and 4.3 × 109 s-1, respectively, considerably slower than the rate constants associated with molecular wires. Even slower rate constants are observed for alternating or random base sequences such as those encountered in natural DNA. The efficiency of charge separation in capped hairpins with A-tract sequences is also low as a consequence of the competition of hole hopping with charge recombination. Significantly higher efficiencies for charge separation are possible using diblock purine base sequences consisting of two or three adenines followed by a larger number of guanines. The short A-block serves as a molecular rectifier, slowing down charge recombination. More efficient charge separation can also be achieved using non-natural bases or by using the triplet acceptor anthraquinone for hole injection.

Original languageEnglish
Pages (from-to)1379-1387
Number of pages9
JournalPure and Applied Chemistry
Volume85
Issue number7
DOIs
Publication statusPublished - 2013

Fingerprint

Charge transfer
Rate constants
DNA
Wire
Stilbenes
Anthraquinones
Guanine
Adenine
Chromophores
Electrons
purine

Keywords

  • DNA
  • Electron transfer
  • Hole hopping
  • Photochemistry
  • Superexchange

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Dynamics and efficiency of photoinduced charge transport in DNA : Toward the elusive molecular wire. / Lewis, Frederick D.; Wasielewski, Michael R.

In: Pure and Applied Chemistry, Vol. 85, No. 7, 2013, p. 1379-1387.

Research output: Contribution to journalArticle

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