Two-Dimensional fes-Topology Covalent Organic Frameworks With Intrinsic Paramagnetic Semiconducting Properties.
Abstract
The structural diversity and periodic arrangement of two-dimensional (2D) covalent organic frameworks (COFs) endow them with great promise for electronic and magnetic functionalities. Nevertheless, magnetic functionalities in semiconducting 2D COFs are not easily attainable due to the scarcity of effective topology diagrams and building blocks. In this study, we designed and synthesized three examples of fes-topology COFs by rationally tessellating octagonal and rhombic pores using redox-active building blocks. The resulting fes-net COFs exhibit high crystallinity, excellent porosity, and well-resolved pore structures. Furthermore, the highly ordered orthogonal arrangement of the embedded redox-active units endows these fes-net COFs with electrical conductivities up to 10-2 S cm-1. In particular, Cu-BBFPP-TQTA-COF displayed enhanced paramagnetic properties attributed to the generated stable tetrathiafulvalene radical species. This work provides an effective design strategy for constructing octagonal fes-COFs and offers new insights into the development of semiconducting magnets.