Issue 39, 2019

Selective access to either a doubly boron-doped tetrabenzopentacene or an oxadiborepin from the same precursor

Abstract

The well-known red emitter tetrabenzo[de,hi,op,st]pentacene (TBPA) has been transformed into a bright blue emitter (B2-TBPA; λem = 472 nm; c-hexane) via substitutional doping with two boron atoms. In contrast to the electron-rich TBPA, which forms endo-peroxides with O2 under daylight, the benchtop-stable B2-TBPA is a good electron acceptor and undergoes reversible reduction at a moderate half-wave potential of E1/2 = −1.73 V (vs. FcH/FcH+; THF). Although the size of B2-TBPA falls within the nanoscale, the helically twisted compound readily dissolves in c-hexane and does not require solubilizing substituents. The synthesis of B2-TBPA is based on the nickel-mediated Yamamoto-type dehalogenation of tetrabrominated 9,10-di(naphth-1-yl)-9,10-dihydro-9,10-diboraanthracene. This intramolecular C–C heterocoupling reaction shows a remarkable solvent dependence: B2-TBPA forms only in pyridine (79% yield), whereas an oxadiborepin is obtained from THF solutions (ODBE, 81%; the reaction mixture is quenched with air in both cases). Insight into the corresponding reaction mechanism was gained from the isolation of intermediates and an investigation of their chemical properties. ODBE is an interesting blue emitter in its own right. Furthermore, it can be ring-opened with excess BBr3 at the B–O–B moiety to afford a dimeric borabenzo[de]anthracene.

Graphical abstract: Selective access to either a doubly boron-doped tetrabenzopentacene or an oxadiborepin from the same precursor

Supplementary files

Article information

Article type
Edge Article
Submitted
24 Jun 2019
Accepted
31 Jul 2019
First published
31 Jul 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2019,10, 9017-9027

Selective access to either a doubly boron-doped tetrabenzopentacene or an oxadiborepin from the same precursor

J. Radtke, K. Schickedanz, M. Bamberg, L. Menduti, D. Schollmeyer, M. Bolte, H. Lerner and M. Wagner, Chem. Sci., 2019, 10, 9017 DOI: 10.1039/C9SC03115D

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