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NIR‐Absorbing π‐Extended Azulene: Non‐Alternant Isomer of Terrylene Bisimide
Author(s) -
Pigulski Bartłomiej,
Shoyama Kazutaka,
Würthner Frank
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202005376
Subject(s) - azulene , aromaticity , chemistry , moiety , electrophilic aromatic substitution , computational chemistry , photochemistry , density functional theory , antiaromaticity , stereochemistry , molecule , organic chemistry
The first planar π‐extended azulene that retains aromaticity of odd‐membered rings was synthesized by [3+3] peri ‐annulation of two naphthalene imides at both long‐edge sides of azulene. Using bromination and subsequent nucleophilic substitution by methoxide and morpholine, selective functionalization of the π‐extended azulene was achieved. Whilst these new azulenes can be regarded as isomers of terrylene bisimide they exhibit entirely different properties, which include very narrow optical and electrochemical gaps. DFT, TD‐DFT, as well as nucleus‐independent chemical shift calculations were applied to explain the structural and functional properties of these new π scaffolds. Furthermore, X‐ray crystallography confirmed the planarity of the reported π‐scaffolds and aromaticity of their azulene moiety.