カルボン酸の水素結合で組み上げた多孔質有機フレームワーク

抄録

Among porous molecular crystals that are formed via self-assembly of organic molecules, those constructed through preorganized hydrogen bonds, named hydrogen-bonded organic frameworks (HOFs), recently attract much attention as new porous organic materials because of their high crystallinity, potential designability, and facile construction process. HOFs, however, are relatively fragile and their current designing strategy is still insufficient compared with other porous materials such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) because of weakness of H-bonds. Stable HOFs with permanent porosity have been required. In connection with this, we have demonstrated that various C₃-symmetric π-conjugated molecules possessing o-bis(4-carboxyphenyl)aryl groups in their periphery successfully gave H-bonding low-density networked structures, which effectively gave stable HOFs with permanent porosity by activation (removal of included solvent molecules). The obtained HOFs show significant thermal stability over 300 °C and permanent porosity with the Brunauer-Emmett-Teller (BET) surface area values up to 1288 m²g⁻¹. The frameworks also can work as a platform to achieve very unique alignment of functional molecules such as C₆₀. Moreover, optelectronic properties of π-conjugated systems applied for the building blocks enabled to provide multifunctional HOFs such as acid-responsive HOFs with permanent porosity. Our strategy for constructing functional HOFs contribute to developing a new field of porous organic materials.