Tracking Hole Transport in DNA Hairpins Using a Phenylethynylguanine Nucleobase

Kristen E. Brown, Arunoday P.N. Singh, Yi Lin Wu, Ashutosh Kumar Mishra, Jiawang Zhou, Frederick D. Lewis*, Ryan M. Young, Michael R. Wasielewski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


The hole transport dynamics of DNA hairpins possessing a stilbene electron acceptor and donor along with a modified guanine (G) nucleobase, specifically 8-(4′-phenylethynyl)deoxyguanosine, or EG, have been investigated. The nearly indistinguishable oxidation potentials of EG and G and unique spectroscopic characteristics of EG+• make it well-suited for directly observing transient hole occupation during charge transport between a stilbene electron donor and acceptor. In contrast to the cation radical G+•, EG+• possesses a strong absorption near 460 nm and has a distinct Raman-active ethynyl stretch. Both spectroscopic characteristics are easily distinguished from those of the stilbene donor/acceptor radical ion chromophores. Employing EG, we observe its role as a shallow hole trap, or as an intermediate hole transport site when a deeper trap state is present. Using a combination of ultrafast absorption and stimulated Raman spectroscopies, the hole-transport dynamics are observed to be similar in systems having EG vs G bases, with small perturbations to the charge transport rates and yields. These results show EG can be deployed at specified locations throughout the sequence to report on hole occupancy, thereby enabling detailed monitoring of the hole transport dynamics with base-site specificity.

Original languageEnglish (US)
Pages (from-to)12084-12092
Number of pages9
JournalJournal of the American Chemical Society
Issue number34
StatePublished - Aug 30 2017

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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