Electron-Deficient Heteroacenes that Contain Two Boron Atoms: Near-Infrared Fluorescence Based on a Push–Pull Effect

18 May 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Electron-deficient heteroacenes that contain two tricoordinate boron atoms in their acene skeletons and planarized phenyl ether moieties at their periphery were synthesized via the borylation of the corresponding silicon-bridged precursors. X-ray crystallographic analysis revealed quinoidal structures, which give rise to two-step reversible redox processes for both the reduction and oxidation. These compounds exhibit intense absorption and sharp fluorescence bands with vibronic structures in the near-infrared (NIR) region. These properties originate from the push–pull effect along the long axis of the molecule derived from the electron-donating ether moiety and the electron-accepting boron moieties. Of particular note is the NIR emission of the thienothiophene-centered heteroacene, which has a maximum at 952 nm with a narrow band width of 309 cm–1 in cyclohexane. A Franck–Condon analysis revealed the crucial role of the sterically less-hindered thienothiophene spacer in achieving this sharp emission band.


near infrared fluorescence
push–pull effect
Franck–Condon analysis

Supplementary materials

Si ChemRxiv


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.