Creation of hydrogen-bonded porous materials with dynamic behaviors

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01919
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Osaka University
• Principal Investigator: Hisaki Ichiro 大阪大学, 大学院基礎工学研究科, 教授 (90419466)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 水素結合 / 多孔質構造体 / 単結晶 / 構造転移 / 外部刺激応答性 / フォトクロミック / 結晶工学 / 超分子化学

Outline of Final Research Achievements

A shape, size, and chemical and electronic properties of porous molecular crystals can be fine-tuned by designing molecular structures. In this study, we have created porous molecular framework connected through hydrogen bonds, so called hydrogen-bonded organic frameworks (HOFs), in which organic molecules programmed with desired functions are spontaneously assembled by hydrogen bonding, and functional sites that can reversibly switch their structures and properties upon external stimuli are incorporated. Specifically, we constructed HOFs that exhibit prominent structural transitions upon desorption of the encapsulated solvent molecules and HOFs that show reversible aperture expansion and contraction upon desorption and re-inclusion. We also constructed stimuli responsive HOFs using molecules whose electronic state and molecular structure change reversibly in response to acid and visible light.

Free Research Field

有機結晶化学

Academic Significance and Societal Importance of the Research Achievements

可逆的な結合の形成と解離が可能な水素結合で分子をネットワーク化したHOFは単結晶を用いた回折測定よりその構造が詳細に解析でき、また構造体の構築、分解、自己修復が容易にできるという特長をもつ。一方、そのような弱い相互作用で形成される構造は脆弱で、内部に空孔もつ低密度結晶を得ること、さらにはその構造を動的に変調させることは困難とされてきた。本研究を通して、これらの問題点が少しずつ解決されつつあり、相反する構造的要求「剛直性と可動性の両立」を満たす多孔質機能材料への道筋を示すことができた。