Abstract
Regulation of electron transfer on organic substances by external stimuli is a fundamental issue in science and technology, which affects organic materials, chemical synthesis, and biological metabolism. Nevertheless, acid/base-responsive organic materials that exhibit reversible electron transfer have not been well studied and developed, owing to the difficulty in inventing a mechanism to associate acid/base stimuli and electron transfer. We discovered a new phenomenon in which N-N linked bicarbazole (BC) and tetramethylbiacridine (TBA) derivatives undergo electron transfer disproportionation by acid stimulus, forming their stable radical cations and reduced species. The reaction occurs through a biradical intermediate generated by the acid-triggered N-N bond cleavage reaction of BC or TBA, which acts as a two electron acceptor to undergo electron transfer reactions with two equivalents of BC or TBA. In addition, in the case of TBA the disproportionation reaction is highly reversible through neutralization with NEt3, which recovers TBA through back electron transfer and N-N bond formation reactions. This highly reversible electron transfer reaction is possible due to the association between the acid stimulus and electron transfer via the acid-regulated N-N bond cleavage/formation reactions which provide an efficient switching mechanism, the ability of the organic molecules to act as multi-electron donors and acceptors, the extraordinary stability of the radical species, the highly selective reactivity, and the balance of the redox potentials. This discovery provides new design concepts for acid/base-regulated organic electron transfer systems, chemical reagents, or organic materials.
| Original language | English |
|---|---|
| Pages (from-to) | 4160-4173 |
| Number of pages | 14 |
| Journal | Chemical Science |
| Volume | 6 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2015 Jul 1 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Chemistry(all)
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Acid/base-regulated reversible electron transfer disproportionation of N-N linked bicarbazole and biacridine derivatives. / Pandit, Palash; Yamamoto, Koji; Nakamura, Toshikazu; Nishimura, Katsuyuki; Kurashige, Yuki; Yanai, Takeshi; Nakamura, Go; Masaoka, Shigeyuki; Furukawa, Ko; Yakiyama, Yumi; Kawano, Masaki; Higashibayashi, Shuhei.
In: Chemical Science, Vol. 6, No. 7, 01.07.2015, p. 4160-4173.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Acid/base-regulated reversible electron transfer disproportionation of N-N linked bicarbazole and biacridine derivatives
AU - Pandit, Palash
AU - Yamamoto, Koji
AU - Nakamura, Toshikazu
AU - Nishimura, Katsuyuki
AU - Kurashige, Yuki
AU - Yanai, Takeshi
AU - Nakamura, Go
AU - Masaoka, Shigeyuki
AU - Furukawa, Ko
AU - Yakiyama, Yumi
AU - Kawano, Masaki
AU - Higashibayashi, Shuhei
PY - 2015/7/1
Y1 - 2015/7/1
N2 - Regulation of electron transfer on organic substances by external stimuli is a fundamental issue in science and technology, which affects organic materials, chemical synthesis, and biological metabolism. Nevertheless, acid/base-responsive organic materials that exhibit reversible electron transfer have not been well studied and developed, owing to the difficulty in inventing a mechanism to associate acid/base stimuli and electron transfer. We discovered a new phenomenon in which N-N linked bicarbazole (BC) and tetramethylbiacridine (TBA) derivatives undergo electron transfer disproportionation by acid stimulus, forming their stable radical cations and reduced species. The reaction occurs through a biradical intermediate generated by the acid-triggered N-N bond cleavage reaction of BC or TBA, which acts as a two electron acceptor to undergo electron transfer reactions with two equivalents of BC or TBA. In addition, in the case of TBA the disproportionation reaction is highly reversible through neutralization with NEt3, which recovers TBA through back electron transfer and N-N bond formation reactions. This highly reversible electron transfer reaction is possible due to the association between the acid stimulus and electron transfer via the acid-regulated N-N bond cleavage/formation reactions which provide an efficient switching mechanism, the ability of the organic molecules to act as multi-electron donors and acceptors, the extraordinary stability of the radical species, the highly selective reactivity, and the balance of the redox potentials. This discovery provides new design concepts for acid/base-regulated organic electron transfer systems, chemical reagents, or organic materials.
AB - Regulation of electron transfer on organic substances by external stimuli is a fundamental issue in science and technology, which affects organic materials, chemical synthesis, and biological metabolism. Nevertheless, acid/base-responsive organic materials that exhibit reversible electron transfer have not been well studied and developed, owing to the difficulty in inventing a mechanism to associate acid/base stimuli and electron transfer. We discovered a new phenomenon in which N-N linked bicarbazole (BC) and tetramethylbiacridine (TBA) derivatives undergo electron transfer disproportionation by acid stimulus, forming their stable radical cations and reduced species. The reaction occurs through a biradical intermediate generated by the acid-triggered N-N bond cleavage reaction of BC or TBA, which acts as a two electron acceptor to undergo electron transfer reactions with two equivalents of BC or TBA. In addition, in the case of TBA the disproportionation reaction is highly reversible through neutralization with NEt3, which recovers TBA through back electron transfer and N-N bond formation reactions. This highly reversible electron transfer reaction is possible due to the association between the acid stimulus and electron transfer via the acid-regulated N-N bond cleavage/formation reactions which provide an efficient switching mechanism, the ability of the organic molecules to act as multi-electron donors and acceptors, the extraordinary stability of the radical species, the highly selective reactivity, and the balance of the redox potentials. This discovery provides new design concepts for acid/base-regulated organic electron transfer systems, chemical reagents, or organic materials.
UR - http://www.scopus.com/inward/record.url?scp=84935877299&partnerID=8YFLogxK
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U2 - 10.1039/c5sc00946d
DO - 10.1039/c5sc00946d
M3 - Article
AN - SCOPUS:84935877299
VL - 6
SP - 4160
EP - 4173
JO - Chemical Science
JF - Chemical Science
SN - 2041-6520
IS - 7
ER -