Synthesis, Hole Doping, and Electrical Properties of a Semiconducting Azatriangulene-Based Covalent Organic Framework

Abstract

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.

Hexaazatriphenylene‐Based Two‐Dimensional Conductive Covalent Organic Framework with Anisotropic Charge Transfer

“…Compared with the HD‐COF film, the XPS survey spectrum of the MB@HD‐COF film showed antimony (Sb) and chlorine (Cl) peaks, indicating the presence of MB. Specifically, the high‐resolution XPS N 1s spectrum of the MB@HD‐COF film revealed an additional peak at 401.55 eV, demonstrating electron transfer from the HAT core in the HD‐COF film to tris(4‐bromophenyl)ammoniumyl radical cation [16–17] . This resulted in the conversion of neutral tris(4‐bromophenyl)amine, which was mostly washed off by DCM during the work‐up procedure.…”

“…HAT core in the HD-COF film to tris(4bromophenyl)ammoniumyl radical cation. [16][17] This resulted in the conversion of neutral tris(4-bromophenyl)amine, which was mostly washed off by DCM during the work-up…”

Gold(I)-Organic Frameworks as Catalysts for Carboxylation of Alkynes with CO2

“…These results suggested the high reactivity of the amine group in 1 , which encouraged us to construct Au-CTC-based MOFs via a formal transimination reaction. Formal transimination reactions have been employed under solvothermal conditions to obtain target covalent organic frameworks (COFs) with high crystallinity. − Here, we demonstrated rapid and scalable formal transimination reactions that were successfully performed at rt. Typically, compound 1 and dialdehyde linkers (i.e., TA , TFTA , DHTA , or DMTA ) were added into a mixture of mesitylene and 6 M acetic acid (v/v, 10/1) at rt for 15 min to give yellow crystalline powders named JNM-Au-n ( n = 1, 2, 3, or 4) in almost quantitative yields (Figure a, see Supporting Information for details).…”

2D Covalent Organic Frameworks with Kagome Lattice: Synthesis and Applications

“…Heteroatom-centered triangulene derivatives integrated COFs are theoretically ideal metal-free photocatalysts for water splitting, [56] and a few of them have been experimentally realized. [57] Besides, it has been demonstrated two C 2v -symmetric trigonal building blocks theoretically assemble the kgm lattice, which provides a new vision helpful to guiding the construction of 2D kgm COFs. [58] On the other hand, the research on topology related performances of 2D kgm COFs are urgently needed.…”