[2 + 2] photodimerization of naphthylvinylpyridines through cation-π interactions in acidic solution

Shinji Yamada; Yuka Nojiri; Shunichi Fukuzumi

doi:10.3390/molecules22030491

[2 + 2] photodimerization of naphthylvinylpyridines through cation-π interactions in acidic solution

Shinji Yamada, Yuka Nojiri, Shunichi Fukuzumi

Department of Chemistry & Nanoscience

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Irradiation of (E)-4-(2-(2-naphthyl)vinyl)pyridine (1a) and (E)-4-(2-(1-naphthyl)vinyl)pyridine (1b) with a 250 W high-pressure mercury lamp in acidic solution afforded synHT dimers in high stereoselectivities. Similar results were obtained by visible light irradiation. On the other hand, when the reactions were carried out under neutral conditions, the stereoselectivities were very low, and the yields were decreased by visible light irradiation. Comparison of the UV-vis spectra between the acidic and the neutral conditions elucidated that the red shift was observed in acidic solutions. These results show that HCl plays essential roles not only in the preorientation of substrates through cation-π interactions, but also in the changes in the absorption properties of substrates that enable visible light reactions.

Original language	English
Article number	491
Journal	Molecules
Volume	22
Issue number	3
DOIs	https://doi.org/10.3390/molecules22030491
State	Published - Mar 2017

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© 2017 by the authors. Licensee MDPI, Basel, Switzerland.

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title = "[2 + 2] photodimerization of naphthylvinylpyridines through cation-π interactions in acidic solution",

abstract = "Irradiation of (E)-4-(2-(2-naphthyl)vinyl)pyridine (1a) and (E)-4-(2-(1-naphthyl)vinyl)pyridine (1b) with a 250 W high-pressure mercury lamp in acidic solution afforded synHT dimers in high stereoselectivities. Similar results were obtained by visible light irradiation. On the other hand, when the reactions were carried out under neutral conditions, the stereoselectivities were very low, and the yields were decreased by visible light irradiation. Comparison of the UV-vis spectra between the acidic and the neutral conditions elucidated that the red shift was observed in acidic solutions. These results show that HCl plays essential roles not only in the preorientation of substrates through cation-π interactions, but also in the changes in the absorption properties of substrates that enable visible light reactions.",

author = "Shinji Yamada and Yuka Nojiri and Shunichi Fukuzumi",

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T1 - [2 + 2] photodimerization of naphthylvinylpyridines through cation-π interactions in acidic solution

AU - Yamada, Shinji

AU - Nojiri, Yuka

AU - Fukuzumi, Shunichi

PY - 2017/3

Y1 - 2017/3

N2 - Irradiation of (E)-4-(2-(2-naphthyl)vinyl)pyridine (1a) and (E)-4-(2-(1-naphthyl)vinyl)pyridine (1b) with a 250 W high-pressure mercury lamp in acidic solution afforded synHT dimers in high stereoselectivities. Similar results were obtained by visible light irradiation. On the other hand, when the reactions were carried out under neutral conditions, the stereoselectivities were very low, and the yields were decreased by visible light irradiation. Comparison of the UV-vis spectra between the acidic and the neutral conditions elucidated that the red shift was observed in acidic solutions. These results show that HCl plays essential roles not only in the preorientation of substrates through cation-π interactions, but also in the changes in the absorption properties of substrates that enable visible light reactions.

AB - Irradiation of (E)-4-(2-(2-naphthyl)vinyl)pyridine (1a) and (E)-4-(2-(1-naphthyl)vinyl)pyridine (1b) with a 250 W high-pressure mercury lamp in acidic solution afforded synHT dimers in high stereoselectivities. Similar results were obtained by visible light irradiation. On the other hand, when the reactions were carried out under neutral conditions, the stereoselectivities were very low, and the yields were decreased by visible light irradiation. Comparison of the UV-vis spectra between the acidic and the neutral conditions elucidated that the red shift was observed in acidic solutions. These results show that HCl plays essential roles not only in the preorientation of substrates through cation-π interactions, but also in the changes in the absorption properties of substrates that enable visible light reactions.

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[2 + 2] photodimerization of naphthylvinylpyridines through cation-π interactions in acidic solution

Abstract

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