Oct 2, 2019
Synthesis and Isolation of Antiaromatic Expanded Azacoronene via Intramolecular Vilsmeier-Type Reaction
Journal of the American Chemical Society
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- Volume
- 141
- Number
- 41
- First page
- 16255
- Last page
- 16259
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1021/jacs.9b09260
Copyright © 2019 American Chemical Society. An antiaromatic cation of the expanded hexapyrrolohexaazacoronene (HPHAC) 1+ was synthesized by a Vilsmeier-type reaction of the partially unfused HPHAC 2. X-ray diffraction analysis revealed the formation of a seven-membered ring with a methyne linkage between the pyrrole moieties. Although 1+ is a monocation, upfield shifts of the peripheral ethyl protons were clearly observed in the 1H NMR spectra, indicating 24πantiaromaticity. Global antiaromaticity was also supported by nucleus-independent chemical shift and anisotropy of the induced current density calculations. Cation 1+ displayed two reversible oxidations and one irreversible reduction in the cyclic voltammetry measurements. Treatment of 1+ with NOSbF6 gave aromatic trication 13+ with 22π-electron conjugation.
- Link information
- ID information
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- DOI : 10.1021/jacs.9b09260
- ISSN : 0002-7863
- eISSN : 1520-5126
- Pubmed ID : 31577141
- SCOPUS ID : 85073010734