Semiconducting Covalent Organic Frameworks based on Trioxotriangulene Neutral Radicals

Résumé fourni par la source

Electrically conductive two-dimensional covalent organic frameworks (2D COFs) have emerged as a versatile class of crystalline porous polymers with promising applications in electronics and energy storage. However, high conductivities are typically achieved via post-synthetic doping to generate charge carriers, which can compromise crystallinity, porosity, and structural homogeneity. Persistent neutral radical conductors provide an attractive alternative, as their unpaired electrons can generate free charge carriers without the need for counterions. Nevertheless, the incorporation of highly delocalized p-radicals into COFs remains largely unexplored. Herein, we report the design and synthesis of imine-linked 2D COFs incorporating spin-delocalized trioxotriangulene (TOT) neutral radicals through two complementary synthetic approaches. Direct use of a TOT radical derivative functionalized with free amine groups affords a highly crystalline framework (TOT-COF-H) that exhibits semiconducting behavior (s RT = 1.2 × 10 -4 S cm -1 ), a reduced band gap ( E g = 1.09 eV), and low activation energy (0.24 eV). This work demonstrates a viable strategy for integrating spin-delocalized neutral radical building blocks into COFs, enabling the development of intrinsically conductive, porous, and crystalline organic frameworks without the need for extrinsic doping.

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