Rational Synthesis of Antiaromatic 5,15‐Dioxaporphyrin and Oxidation into β,β‐Linked Dimers |
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| Authors: | Akihide Nishiyama Masaya Fukuda Dr. Shigeki Mori Prof. Dr. Ko Furukawa Dr. Heike Fliegl Prof. Dr. Hiroyuki Furuta Prof. Dr. Soji Shimizu |
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| Affiliation: | 1. Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan;2. Advanced Research Support Center (ADRES), Ehime University, Matsuyama, Japan;3. Center for Instrumental Analysis, Institute for Research Promotion, Niigata University, Niigata, Japan;4. Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Oslo, Norway;5. Center for Molecular Systems (CMS), Kyushu University, Fukuoka, Japan |
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| Abstract: | 5,15‐Dioxaporphyrin was synthesized for the first time by a nucleophilic aromatic substitution reaction of a nickel bis(α,α′‐dibromodipyrrin) complex with benzaldoxime, followed by an intramolecular annulation of the α‐hydroxy‐substituted intermediate. This unprecedented molecule is a 20π‐electron antiaromatic system, in terms of Hückel's rule of aromaticity, because lone pair electrons of oxygen atoms are incorporated into the 18π‐electron conjugated system of the porphyrin. A theoretical analysis based on the gauge‐including magnetically induced current method confirmed its antiaromaticity and a dominant inner ring pathway for the ring current. The unique reactivity of 5,15‐dioxaporphyrin forming a β,β‐linked dimer upon oxidation was also revealed. |
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| Keywords: | aromaticity dimers heterocycles porphyrinoids redox chemistry |
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