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Homochiral Covalent Organic Frameworks with Superhelical Nanostructures Enable Efficient Chirality-Induced Spin
Bang Hou1, Kaixuan Wang1, Chao Jiang1
1School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 200240, Shanghai, China.
Angewandte Chemie (International Ed. in English)
|August 24, 2024
Summary
Researchers created superhelical covalent organic framework (COF) nanofibers by adjusting linker lengths. These chiral COFs show enhanced enantioselectivity and spin-filter properties, advancing nanomaterial applications.
Area of Science:
- Materials Science
- Nanotechnology
- Organic Chemistry
Background:
- Covalent organic frameworks (COFs) offer tunable properties but achieving complex nanostructures like superhelices is difficult.
- Homochiral COFs with controlled morphologies are crucial for advanced applications in chiral recognition and spintronics.
Purpose of the Study:
- To develop a method for synthesizing homochiral superhelical COF nanofibers.
- To investigate the influence of linker structure on COF morphology and properties.
- To evaluate the chiral recognition and spin-filter capabilities of the synthesized superhelical COFs.
Main Methods:
- Synthesis of homochiral 3D COFs (13-OR) using enantiopure 1,1'-bi-2-naphthol (BINOL)-based tetraaldehydes and tetraamines with varying alkyl chain lengths.
- Characterization of COF morphology and structure, including time-tracking of self-assembly processes.
- Assessment of chiral recognition via carbohydrate binding and measurement of chiral-induced spin selectivity (CISS) effect.
Main Results:
- Controlled synthesis of homochiral superhelical COF nanofibers achieved by manipulating pendent alkyl chain lengths.
- COF-13-OEt, with optimal ethoxyl substituents, exhibited macroscopic chirality in superhelical fibers, while other analogs formed spherical or non-helical structures.
- Superhelical COFs demonstrated significantly enhanced enantioselectivity in carbohydrate binding (up to six times higher) and a high spin polarization ratio (48-51%) due to the CISS effect.
Conclusions:
- Alkyl chain length in organic linkers is a critical factor for directing the formation of superhelical COF nanostructures.
- The synthesized superhelical COFs exhibit promising applications in chiral sensing and spin-based electronics.
- The study provides a new pathway for fabricating complex chiral nanomaterials with tailored functionalities.
Keywords:
chiral-induced spin selectivitycovalent organic frameworkenantiodiscriminationmacroscopic chiralitysuperhelical nanostructuresMore Related Videos
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