Two-dimensional covalent organic frameworks (2D COFs)
containing
heterotriangulenes have been theoretically identified as semiconductors
with tunable, Dirac-cone-like band structures, which are expected
to afford high charge-carrier mobilities ideal for next-generation
flexible electronics. However, few bulk syntheses of these materials
have been reported, and existing synthetic methods provide limited
control of network purity and morphology. Here, we report transimination
reactions between benzophenone-imine-protected azatriangulenes (OTPA)
and benzodithiophene dialdehydes (BDT), which afforded a new semiconducting
COF network, OTPA-BDT. The COFs were prepared as both polycrystalline
powders and thin films with controlled crystallite orientation. The
azatriangulene nodes are readily oxidized to stable radical cations
upon exposure to an appropriate p-type dopant, tris(4-bromophenyl)ammoniumyl
hexachloroantimonate, after which the network’s crystallinity
and orientation are maintained. Oriented, hole-doped OTPA-BDT COF
films exhibit electrical conductivities of up to 1.2 × 10–1 S cm–1, which are among the highest
reported for imine-linked 2D COFs to date.
Interrogating the stacking of two-dimensional polymers (2DPs) as a function of chemical composition is important to leverage their properties. We explore the dependence of 2DP crystallinity and porosity on variable...
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