title: Tuning Lewis Acidity by a Transannular pπ-σ* Interaction between Boron and Silicon/Germanium Atoms Supported by a Cage-Shaped Framework.
abstract: Cage-shaped borates tethered by heavier Group 14 elements (Si or Ge) were synthesized. These possess an intramolecularly transannular pπ-σ* interaction between the boron center and the tethered Si/Ge atom, which allows the precise tuning of their Lewis acidity. The Lewis acidity was investigated by the ligand-exchange reaction rate and IR measurements with the help of theoretical calculation. The synthesized borates exhibited catalytic activity. This study demonstrated the effectiveness of the direct orbital perturbation of a metal center by space interaction during fine tuning of the Lewis acidity.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.|Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Akihito
authors.identifier: http://orcid.org/0000-0002-3438-786X
authors.initials: A
authors.lastname: Konishi
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakaoka
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Nakajima
authors.affiliation: Science and Technology System Division, Ryoka Systems Inc., Tokyo Skytree East Tower, 1-1-2 Oshiage, Sumida-ku, Tokyo, 131-0045, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Chiba
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Baba
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Makoto
authors.identifier: http://orcid.org/0000-0002-6618-2893
authors.initials: M
authors.lastname: Yasuda
keywords: Lewis acids; cage-shaped borates; germanium; pi interactions; silicon