巨大な開口部を有するキラル金属－有機ナノチューブの開発

2017 Fiscal Year Annual Research Report

• Project/Area Number: 16F16337
• Research Institution: The University of Tokyo
• Principal Investigator: 佐藤 弘志 東京大学, 大学院工学系研究科(工学部), 講師 (20598586)
• Co-Investigator(Kenkyū-buntansha): MENG WENJING 東京大学, 工学(系)研究科(研究院), 外国人特別研究員
• Project Period (FY): 2016-11-07 – 2019-03-31
• Keywords: 多孔体 / 結晶 / 配位高分子 / カテナン

Outline of Annual Research Achievements

We have been working on the project about catenane-based responsive metal-organic frameworks (MOFs). Catenanes have been widely studied in solution as an individual molecule. Their dynamic properties are particularly interesting as they can lead to the potential application as molecular switches. We are keen to understand how the mechanical bond of catenane can bring dynamic properties to the usually rigid solid-state material: MOFs.
The synthesis of suitable ligand has been a challenge. In many reactions, catenanes are formed in competition with other macrocycles and oligomers. As a result, the yield of desired catenane product is low. The synthesis has been performed many times during several months in order to obtain enough ligand.
The reaction between the ligand and metal ions such as zinc (II) resulted in a three-dimensional metal-organic framework which has been successfully characterized by single-crystal X-ray crystallography after several months’ trial. The synthetic method of MOF was optimized in order to obtain crystals with good enough quality for X-ray diffraction. The crystal was found to be sensitive to solvent loss, which took us a long time to learn how to handle it properly. The MOF showed temperature-dependent polymorphism, as observed through single-crystal X-ray crystallography. The dynamic property of the MOF was also characterized by powder X-ray diffraction and gas sorption.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

従来まったく報告のない結合様式から構成された新規金属ー有機構造体の合成に成功し、論文投稿直前まで研究を進捗させた。

Strategy for Future Research Activity

これまでに合成した結晶性材料の構造ならびに基本的な物性は以下の通りであった。（１）従来用いられたことのない「カテナン構造」から成る3次元骨格を有し、（２）温度・ゲスト分子の有無に応じて細孔構造を可逆的に変化させる。これら新規構造・物性の起源を詳細に明らかにすると共に、一連の化合物群合成を行うことで、新たな材料設計指針を構築する。