3D Cage COFs: A Dynamic Three-Dimensional Covalent Organic Framework with High-Connectivity Organic Cage Nodes
Qiang Zhu1, Xue Wang1,2, Rob Clowes1
1Department of Chemistry and Materials Innovation Factory, University of Liverpool, Liverpool L7 3NY, United Kingdom.
Abstract:
Three-dimensional (3D) covalent organic frameworks (COFs) are rare because there is a limited choice of organic building blocks that offer multiple reactive sites in a polyhedral geometry. Here, we synthesized an organic cage molecule (Cage-6-NH) that was used as a triangular prism node to yield the first cage-based 3D COF, 3D-CageCOF-1. This COF adopts an unreported 2-fold interpenetrated acs topology and exhibits reversible dynamic behavior, switching between a small-pore (sp) structure and a large-pore (lp) structure. It also shows high CO2 uptake and captures water at low humidity (<40%). This demonstrates the potential for expanding the structural complexity of 3D COFs by using organic cages as the building units.
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