| Autor: |
Masanobu Uchiyama, Tetsuro Majima, Mamoru Fujitsuka, Shigeru Yamago, Eiichi Kayahara, Atsuya Muranaka, Taisei Osawa, Naoyuki Toriumi, Yui Masumoto |
| Rok vydání: |
2021 |
| DOI: |
10.26434/chemrxiv.14708859 |
| Popis: |
The concept of aromaticity is essential for chemists to understand the nature of many chemical substances. “In-plane” aromaticity is a unique type of aromaticity found in some π-conjugated systems consisting of radially oriented p-orbitals. Although in-plane aromaticity has been theoretically predicted about 40 years ago, its intrinsic properties are much less well understood than those of conventional Hückel aromatic systems with perpendicularly oriented p-orbitals because of lack of available examples of in-plane aromatic molecules. Here we demonstrate, from both theoretical and experimental aspects, that in-plane aromaticity of cycloparaphenylenes is reversed upon excitation to the lowest triplet state. In-plane non-aromatic neutral forms with a 4N-electron system and in-plane aromatic dications with a 4N+2-electron system turn out to be aromatic and anti-aromatic, respectively, indicating that Baird’s rule holds for the in-plane aromatic system. Armchair carbon nanotube fragments based on the cycloparaphenylene were also found to follow Baird’s rule from a magnetic viewpoint. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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