Three-Dimensional Fully Conjugated Covalent Organic Frameworks from a Hexaconnected sp2-Carbon Building Unit
Jie Zhang1, Chuanbao Jiao1, Haorui Zheng1
1State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, P. R. China.
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Fully conjugated two-dimensional materials have enabled groundbreaking advances in organic electronics and photocatalysis, yet extending these properties into the third dimension remains a formidable synthetic challenge, primarily due to the scarcity of high-connectivity conjugated building blocks. Herein, we report the design and synthesis of an unprecedented 6-connected, all sp2-hybridized carbon building block, cyclododecahexaene-hexathiophene-hexaaldehyde (CDHTh-6CHO), and its successful incorporation into a series of three-dimensional covalent organic frameworks (3D-CDHTh-COFs, designated JUC-690, -691, -692). These frameworks constitute the first examples of 3D COFs constructed from a high-connected conjugated core. The extended π-conjugation throughout the 3D skeleton endows these materials with exceptional charge transport properties, exhibiting band-like transport behavior with tunable Hall electron mobilities (up to 1.32 cm2 V-1 s-1). Furthermore, the 3D-CDHTh-COFs demonstrate outstanding photocatalytic performance, as evidenced by the highly efficient and selective aerobic oxidation of thioanisole (up to 99%). This work not only introduces a pioneering architecture for high-connected conjugated building blocks but also establishes a new platform of 3D full conjugated COFs with significant potential in optoelectronics and heterogeneous photocatalysis.
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