このエントリーをはてなブックマークに追加
ID 45951
著者
Kida, Motoki
Shimoyama, Daisuke
Ikeda, Toshiaki 大学院理学研究科
Sekiya, Ryo 大学院理学研究科 広大研究者総覧
Haino, Takeharu 大学院理学研究科 広大研究者総覧
Ebata, Takayuki 大学院理学研究科 広大研究者総覧
Jouvet, Christophe
Inokuchi, Yoshiya 大学院理学研究科 広大研究者総覧
NDC
化学
抄録(英)
We observe UV spectra of protonated dibenzylamine (dBAMH+) and its complexes with 15-crown-5 (dBAMH+–15C5), 18-crown-6 (dBAMH+–18C6), and 24-crown-8 (dBAMH+–24C8) under cold (~10 K) gas-phase conditions by UV photodissociation (UVPD) and UV-UV hole-burning (HB) spectroscopy. The UVPD spectrum of the dBAMH+–15C5 complex shows an extensive low-frequency progression, which originates from a unique conformation of the dBAMH+ part with benzene rings facing closely to each other, while UVPD and calculation results suggest open conformations of the dBAMH+ part for dBAMH+–18C6 and dBAMH+–24C8. UV-UV HB spectra of the dBAMH+–24C8 complex indicate that there exist at least two conformers; multiple conformations can contribute to high stability of dBAMH+–24C8 pseudorotaxane due to “conformational” entropic effects. The UVPD experiment indicates that the dissociation probability of dBAMH+–24C8 into dBAMH+ and 24C8 is substantially smaller than that of dBAMH+–15C5 and dBAMH+–18C6, which can be related to the barrier height in the dissociation process. The energetics of the dBAMH+–24C8 complex is investigated experimentally with NMR spectroscopy and theoretically with the global reaction route mapping (GRRM) method. An energy barrier of ~60 kJ mol–1 is present in the pseudorotaxane formation in solution, whereas there is no barrier in the gas phase. In the course of the photodissociation, excited dBAMH+–24C8 complexes can be trapped at many local minima corresponding to multiple conformations. This can result in effective dissipation of internal energy into degrees of freedom not correlated to the dissociation and decrease the dissociation probability for the dBAMH+–24C8 complex in the gas phase. The energy barrier for the pseudorotaxane formation in solution originates not simply from the slippage process but rather from solvent effects on the dBAMH+–24C8 complex.
内容記述
This work was partly supported by the JSPS KAKENHI Grant Number JP16H04098 and the MAEE/JSPS France-Japan Collaboration Program (SAKURA).
掲載誌名
Physical Chemistry Chemical Physics
20巻
27号
開始ページ
18678
終了ページ
18687
出版年月日
2018-07-11
出版者
Royal Society of Chemistry
ISSN
1463-9076
1463-9084
出版者DOI
PubMedID
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
author
権利情報
Copyright (c) the Owner Societies 2018
This is the accepted manuscript of the article is available at https://doi.org/10.1039/C8CP02707B
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
部局名
理学研究科
備考
Post-print version/PDF may be used in an institutional repository after an embargo period of 12 months.