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22 results on '"Akine, Shigehisa"'

8. Real-time chirality transfer monitoring from statistically random to discrete homochiral nanotubes

Author

10879406, 00447682, Fa, Shixin, Shi, Tan-hao, Akama, Suzu, Adachi, Keisuke, Wada, Keisuke, Tanaka, Seigo, Oyama, Naoki, Kato, Kenichi, Ohtani, Shunsuke, Nagata, Yuuya, Akine, Shigehisa, Ogoshi, Tomoki, 10879406, 00447682, Fa, Shixin, Shi, Tan-hao, Akama, Suzu, Adachi, Keisuke, Wada, Keisuke, Tanaka, Seigo, Oyama, Naoki, Kato, Kenichi, Ohtani, Shunsuke, Nagata, Yuuya, Akine, Shigehisa, and Ogoshi, Tomoki

Abstract

Real time monitoring of chirality transfer processes is necessary to better understand their kinetic properties. Herein, we monitor an ideal chirality transfer process from a statistically random distribution to a diastereomerically pure assembly in real time. The chirality transfer is based on discrete trimeric tubular assemblies of planar chiral pillar[5]arenes, achieving the construction of diastereomerically pure trimers of pillar[5]arenes through synergistic effect of ion pairing between a racemic rim-differentiated pillar[5]arene pentaacid bearing five benzoic acids on one rim and five alkyl chains on the other, and an optically resolved pillar[5]arene decaamine bearing ten amines. When the decaamine is mixed with the pentaacid, the decaamine is sandwiched by two pentaacids through ten ion pairs, initially producing a statistically random mixture of a homochiral trimer and two heterochiral trimers. The heterochiral trimers gradually dissociate and reassemble into the homochiral trimers after unit flipping of the pentaacid, leading to chirality transfer from the decaamine and producing diastereomerically pure trimers.

Published
2022

9. State- and water repellency-controllable molecular glass of pillar[5]arenes with fluoroalkyl groups by guest vapors

Author

10879406, 00447682, Onishi, Katsuto, Ohtani, Shunsuke, Kato, Kenichi, Fa, Shixin, Sakata, Yoko, Akine, Shigehisa, Ogasawara, Moe, Asakawa, Hitoshi, Nagano, Shusaku, Takashima, Yoshinori, Mizuno, Motohiro, Ogoshi, Tomoki, 10879406, 00447682, Onishi, Katsuto, Ohtani, Shunsuke, Kato, Kenichi, Fa, Shixin, Sakata, Yoko, Akine, Shigehisa, Ogasawara, Moe, Asakawa, Hitoshi, Nagano, Shusaku, Takashima, Yoshinori, Mizuno, Motohiro, and Ogoshi, Tomoki

Abstract

Molecular glasses are low-molecular-weight organic compounds that are stable in the amorphous state at room temperature. Herein, we report a state- and water repellency-controllable molecular glass by n-alkane guest vapors. We observed that a macrocyclic host compound pillar[5]arene with the C₂F₅ fluoroalkyl groups changes from the crystalline to the amorphous state (molecular glass) by heating above its melting point and then cooling to room temperature. The pillar[5]arene molecular glass shows reversible transitions between amorphous and crystalline states by uptake and release of the n-alkane guest vapors, respectively. Furthermore, the n-alkane guest vapor-induced reversible changes in the water contact angle were also observed: water contact angles increased and then reverted back to the original state by the uptake and release of the n-alkane guest vapors, respectively, along with the changes in the chemical structure and roughness on the surface of the molecular glass. The water repellency of the molecular glass could be controlled by tuning the uptake ratio of the n-alkane guest vapor.

Published
2022

10. State- and water repellency-controllable molecular glass of pillar[5]arenes with fluoroalkyl groups by guest vapors

Author

Onishi, Katsuto, primary, Ohtani, Shunsuke, additional, Kato, Kenichi, additional, Fa, Shixin, additional, Sakata, Yoko, additional, Akine, Shigehisa, additional, Ogasawara, Moe, additional, Asakawa, Hitoshi, additional, Nagano, Shusaku, additional, Takashima, Yoshinori, additional, Mizuno, Motohiro, additional, and Ogoshi, Tomoki, additional

Published
2022
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17. Molecular weight fractionation by confinement of polymer in one-dimensional pillar[5]arene channels

Author

Ogoshi, Tomoki, primary, Sueto, Ryuta, additional, Yagyu, Masafumi, additional, Kojima, Ryosuke, additional, Kakuta, Takahiro, additional, Yamagishi, Tada-aki, additional, Doitomi, Kazuki, additional, Tummanapelli, Anil Kumar, additional, Hirao, Hajime, additional, Sakata, Yoko, additional, Akine, Shigehisa, additional, and Mizuno, Motohiro, additional

Published
2019
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20. Oxime-based salen-type tetradentate ligands with high stability against imine metathesis reaction

Author

Akine, Shigehisa, Taniguchi, Takanori, Dong, Wenkui, Masubuchi, Sayuri, and Nabeshima, Tatsuya

Subjects
Aldehydes -- Chemical properties, Ligands -- Research, Schiff bases -- Research, Biological sciences, Chemistry
Abstract

A series of new ligands salamo (=1,2-bis(salicylideneaminooxy)ethane) on the basis of O-alkyl oxime instead of the imine moiety is synthesized, to develop stable analogues of salen-type ligands. The ligands are prepared by the reaction of 1,2-bis(aminooxy)ethane with two equivalents of salicyladehyde derivatives under mild conditions.

Published
2005

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