Spin-Selective Photoinduced Electron Transfer within Naphthalenediimide Diradicals

Nathan T. La Porte, Joseph A. Christensen, Matthew D. Krzyaniak, Brandon K. Rugg, Michael R. Wasielewski

Research output: Contribution to journalArticle

Abstract

There has been increasing interest in the excited states of stable diradicals as means of manipulating their spin states for potential applications in quantum information science (QIS). In this work, we examine a set of diradicals composed of two stable naphthalene-1,8:4,5-bis(dicarboximide) radical anions (NDI•-) bound either directly at their imide nitrogen atoms or through a series of benzene spacers resulting in diradicals with either singlet or triplet ground states. We use time-resolved near-UV, visible, near-IR, and mid-IR spectroscopy to show that the population in the singlet ground state can undergo photoinduced electron transfer upon excitation of one of the NDI•- radicals to produce the NDI0-NDI2- moiety, while the corresponding triplet population cannot. In particular, spectroscopy in the wavelength region 330-450 nm and in the energy range 1450-1750 cm-1 is critical to distinguishing the two populations. By varying the connectivity between the two radical anions, we vary both the sign and magnitude of the singlet-triplet energy splitting (2J) of the diradicals, thereby varying the proportion of singlet and triplet ground state populations that are detected optically. EPR spectroscopy provides corroborating evidence for the ground spin state of the diradicals. This result has implications for using photoexcitation to manipulate the spin states of diradicals for QIS applications.

Original languageEnglish
Pages (from-to)7731-7739
Number of pages9
JournalJournal of Physical Chemistry B
Volume123
Issue number36
DOIs
Publication statusPublished - Sep 12 2019

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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