【公開日：2024.07.25】【最終更新日：2024.04.04】
課題データ / Project Data
課題番号 / Project Issue Number
23KT0039
利用課題名 / Title
2-アザピレンベースの二次元共役共有結合性有機フレームワークの空間調節
利用した実施機関 / Support Institute
京都大学 / Kyoto Univ.
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）次世代ナノスケールマテリアル/Next-generation nanoscale materials（副 / Sub）-
キーワード / Keywords
電子顕微鏡/ Electronic microscope,ナノ多孔体/ Nanoporuous material
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Li Zhuowei
所属名 / Affiliation
京都大学大学院 工学研究科
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
Masaki Nobuoka
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
小川 哲也
利用形態 / Support Type
（主 / Main）技術代行/Technology Substitution（副 / Sub）,技術代行/Technology Substitution
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
The crystallinity of covalent organic frameworks (COFs) is not only crucial for their structures but also for their related chemical, structural, and optoelectronic properties. The significant advantage of COFs lies in their high degree of freedom in topological design compared to other porous materials. Among the π-conjugated motifs used for constructing COFs, pyrene-based tetragonal structures are particularly effective in achieving highly ordered and crystalline states.In this study, we demonstrated that substituting pyrene with diazapyrene, which lacks hydrogen atoms at the positions controlling the twisting angles of linker molecules, results in nearly "flat" structures of two-dimensional (2D) COF layers. This substitution allows for precise control of the twisting angles of linker molecules. The flat structure of the COF layer leads to ordered face-to-face (slipped AA) stacking configurations with finite pore sizes and high thermodynamic stability up to 500 °C.The planar nature of the diazapyrene-based COFs is reflected in the extended electronic conjugation over 2D frames, resulting in small optical bandgaps (Eg) of approximately 2 eV.
実験 / Experimental
Scanning electron microscopy (SEM) observations unveiled the microstructures of Aza-1P, Aza-1PF, Aza-TT, and Aza-Py, where Aza-1P and Aza-Py crystals manifested rhomboid plate morphologies, each measuring approximately 20–40 μm in size. Further insights from cryo-transmission electron microscopy (Cryo-TEM) highlighted the formation of well-defined periodic frameworks in Aza-1P, Aza-1PF, Aza-TT, and Aza-Py, featuring periodic channels that closely conformed to the π–π stacking configurations as predicted by the structural model. The interlayer distances of Aza-1P, Aza-1PF, and Aza-TT were measured at 2.3 nm, while that of Aza-Py stood at 1.6 nm.
結果と考察 / Results and Discussion
In summary, we have successfully synthesized four diazapyrene-based COFs characterized by high crystallinity and porosity. The reduction in rotation angle of phenylenes contributed to shorter interlayer distances and denser packing of the resulting materials. The combined effect of extended conjugation, facilitated by the relatively planar structure of Aza-1P, and the electronegative nitrogen atom was confirmed through PXRD and diffuse reflectance spectroscopy.Significantly, the Aza-Py COF exhibited a unique structural arrangement where structurally similar units alternated to form distinctive columnar structures. This introduces a novel design guideline for COFs, utilizing subtle differences in rotation angle to achieve distinct stacking patterns.Furthermore, the presence of diazapyrene centers in the synthesized COFs offers potential for proton coordination, with their proton conductivity observed to be temperature-dependent.
図・表・数式 / Figures, Tables and Equations
Fig. 1 TEM image of Aza-1PF COF from different areas.
Fig.2 TEM image of Aza-1PF COF showing 1D channels.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- Zhuowei Li,「2-アザピレンベースの二次元共役共有結合性有機フレームワークの空間調節」、令和4年度第2回高密度共役領域会議、愛知県、2023年3月
- Ultrafine Spatial Modulation of Diazapyrene-Based Two-Dimensional Conjugated Covalent Organic Frameworks Author(s): Li, Zhuowei; Tsuneyuki, Takahiro; Paitandi, Rajendra; Nakazato, Takumi; Odawara, Masahiro ; Tsutsui, Yusuke; Tanaka, Takayuki; Miyake, Yoshihiro; Shinokubo, Hiroshi; Ghosh, Samrat; Seki, Shu. Submitted
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件