Two-dimensional amine and hydroxy functionalized fused aromatic covalent organic framework

Javeed Mahmood,Minbok Jung,Jong-Beom Baek,Young Hyun Kim,Soo-Young Yu,Hyung-Joon Shin,Ishfaq Ahmad,Hyuk-Jun Noh,Jeong-Min Seo

doi:10.1038/s42004-020-0278-1

Javeed Mahmood, Minbok Jung + Show 7 more

Open Access

https://doi.org/10.1038/s42004-020-0278-1

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Abstract

Ordered two-dimensional covalent organic frameworks (COFs) have generally been synthesized using reversible reactions. It has been difficult to synthesize a similar degree of ordered COFs using irreversible reactions. Developing COFs with a fused aromatic ring system via an irreversible reaction is highly desirable but has remained a significant challenge. Here we demonstrate a COF that can be synthesized from organic building blocks via irreversible condensation (aromatization). The as-synthesized robust fused aromatic COF (F-COF) exhibits high crystallinity. Its lattice structure is characterized by scanning tunneling microscopy and X-ray diffraction pattern. Because of its fused aromatic ring system, the F-COF structure possesses high physiochemical stability, due to the absence of hydrolysable weak covalent bonds.

Highlights

Ordered two-dimensional covalent organic frameworks (COFs) have generally been synthesized using reversible reactions
This beneficial intrinsic reversibility limits the COFs practical applications, because it leads to physiochemical instability[4,27]
Due to the formation of fused pyrazine rings in the network-forming reaction, crystalline fused aromatic COF (F-COF) was produced in quantitative yield even in solution, without surface and/or interfacial assistance (Fig. 1)

Summary

Introduction

Ordered two-dimensional covalent organic frameworks (COFs) have generally been synthesized using reversible reactions. Despite a few examples of π-conjugated COFs, obtained using surface or interface-assisted synthesis[10,39,40], the design and synthesis of fused aromatic ring-based π-conjugated COFs, which produces high crystallinity and structural stability in corrosive environments, remains a crucial challenge[41]. Due to the formation of fused pyrazine rings in the network-forming reaction, crystalline F-COF was produced in quantitative yield even in solution, without surface and/or interfacial assistance (Fig. 1).

Results

Conclusion