In-Plane Aromaticity in Cycloparaphenylene Dications: A Magnetic Circular Dichroism and Theoretical Study

In-Plane Aromaticity in Cycloparaphenylene Dications: A Magnetic Circular Dichroism and Theoretical Study

The electronic structures of [8]cyclo­para­phenylene dication ([8]CPP2+) and radical cation ([8]CPP•+) have been investigated by magnetic circular dichroism (MCD) spectroscopy, which enabled unambiguous discrimination between previously conflicting assignments of the UV–vis–NIR absorption spectral b...

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Veröffentlicht in:Journal of the American Chemical Society 2015-01, Vol.137 (1), p.82-85
Hauptverfasser: Toriumi, Naoyuki, Muranaka, Atsuya, Kayahara, Eiichi, Yamago, Shigeru, Uchiyama, Masanobu
Format: Artikel
Sprache:eng
Schlagworte:
Benzene Derivatives - chemistry
Cations - chemistry
Circular Dichroism
Magnetic Phenomena
Molecular Structure
Quantum Theory
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Zusammenfassung:The electronic structures of [8]cyclo­para­phenylene dication ([8]CPP2+) and radical cation ([8]CPP•+) have been investigated by magnetic circular dichroism (MCD) spectroscopy, which enabled unambiguous discrimination between previously conflicting assignments of the UV–vis–NIR absorption spectral bands. Molecular orbital and nucleus-independent chemical shift (NICS) analysis revealed that [8]CPP2+ shows in-plane aromaticity with a (4n + 2) π-electron system (n = 7). This aromaticity appears to be the origin of the unusual stability of the dication. Theoretical calculations further suggested that not only [8]CPP2+ but also all [n]CPP (n = 5–10) dications and dianions exhibit in-plane aromaticity.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja511320f