Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

Kan Tang, Megan R. Brown, Chad Risko, Melissa K. Gish, Garry Rumbles, Phuc H. Pham, Oana R. Luca, Stephen Barlow, Seth R. Marder

Research output: Contribution to journalArticlepeer-review

Abstract

2,2’-Bis(4-dimethylaminophenyl)- and 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole ((N-DMBI)2 and (Cyc-DMBI)2) are quite strong reductants with effective potentials of ca. −2 V vs ferrocenium/ferrocene, yet are relatively stable to air due to the coupling of redox and bond-breaking processes. Here, we examine their use in accomplishing electron transfer-induced bond-cleavage reactions, specifically dehalogenations. The dimers reduce halides that have reduction potentials less cathodic than ca. −2 V vs ferrocenium/ferrocene, especially under UV photoexcitation (using a 365 nm LED). In the case of benzyl halides, the products are bibenzyl derivatives, whereas aryl halides are reduced to the corresponding arenes. The potentials of the halides that can be reduced in this way, quantum-chemical calculations, and steady-state and transient absorption spectroscopy suggest that UV irradiation accelerates the reactions via cleavage of the dimers to the corresponding radical monomers.

Original languageEnglish
Pages (from-to)1912-1922
Number of pages11
JournalBeilstein Journal of Organic Chemistry
Volume19
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 Tang et al.; licensee Beilstein-Institut. License and terms: see end of document.

Keywords

  • dehalogenation
  • n-dopant
  • reduction
  • reductive dimerization

ASJC Scopus subject areas

  • Organic Chemistry

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