Search

Fused aromatic networks (FANs) have been studied in efforts to overcome the low physicochemical stability of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), while preserving crystallinity. Herein, we describe the synthesis of a highly stable and crystalline FAN (denoted as Pz-FAN) using pyrazine-based building blocks to form porphyrazine (Pz) linkages via an irreversible reaction. Unlike most COFs and FANs, which are synthesized from two different building blocks, the new Pz-FAN is formed using a single building block by self-cyclotetramerization. Controlled and optimized reaction conditions result in a highly crystalline Pz-FAN with physicochemical stability. The newly prepared Pz-FAN displayed a high magnitude (1.16×10 -2  S cm -1 ) of proton conductivity compared to other reported FANs and polymers. Finally, the Pz-FAN-based membrane was evaluated for a proton-exchange membrane fuel cell (PEMFC), which showed maximum power and current densities of 192 mW cm -2 and 481 mA cm -2 , respectively., (© 2022 Wiley-VCH GmbH.)

Recently, studies of 2D organic layered materials with unique electronic properties have generated considerable interest in the research community. However, the development of organic materials with functional electrical transport properties is still needed. Here, a 2D fused aromatic network (FAN) structure with a C 5 N basal plane stoichiometry is designed and synthesized, and thin films are cast from C 5 N solution onto silicon dioxide substrates. Then field-effect transistors are fabricated using C 5 N thin flakes as the active layer in a bottom-gate top-contact configuration to characterize their electrical properties. The C 5 N thin flakes, isolated by polydimethylsiloxane stamping, exhibit ambipolar charge transport and extraordinarily high electron (996 cm 2 V -1 s -1 ) and hole (501 cm 2 V -1 s -1 ) mobilities, surpassing the performance of most pristine organic materials without doping. These results demonstrate their vast potential for applications in thin-film optoelectronic devices., (© 2021 Wiley-VCH GmbH.)

There have been extensive efforts to synthesize crystalline covalent triazine-based frameworks (CTFs) for practical applications and to realize their potential. The phosphorus pentoxide (P 2 O 5 )-catalyzed direct condensation of aromatic amide instead of aromatic nitrile to form triazine rings. P 2 O 5 -catalyzed condensation was applied on terephthalamide to construct a covalent triazine-based framework (pCTF-1). This approach yielded highly crystalline pCTF-1 with high specific surface area (2034.1 m 2  g -1 ). At low pressure, the pCTF-1 showed high CO 2 (21.9 wt % at 273 K) and H 2 (1.75 wt % at 77 K) uptake capacities. The direct formation of a triazine-based COF was also confirmed by model reactions, with the P 2 O 5 -catalyzed condensation reaction of both benzamide and benzonitrile to form 1,3,5-triphenyl-2,4,6-triazine in high yield., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)