Synthesis of two-dimensional porous aromatic frameworks via triple condensation reaction

Abstract

Porous aromatic frameworks (PAFs) are composed of aromatic rings which are connected by C–C bonds. A general synthesis method to prepare PAFs is to build new C–C bond among aromatic rings through various cross-coupling reactions by using metal complex catalysts. However, the construction of PAFs through formation of new aromatic rings is rarely mentioned in the literature. In this work, two kinds of two-dimensional (2D) PAFs are obtained by the triple condensation reaction of acetyl aryl compounds. Compared with the general method, this synthetic method has the advantages that the reaction does not require any metal catalysts and can be carried out in the air with high yield. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images display the large-scale 2D structure of the product. 13C solid-state nuclear magnetic resonance (13C ss-NMR) and Fourier-transform infrared (FT-IR) spectra are used to prove the decreasing number of acetyl groups and the formation of aromatic rings after the condensation reaction completed. Thermal gravimetric analysis (TGA) and contact angle (CA) test measurements demonstrate good thermal stability and hydrophobicity of materials. The new types of PAFs are promising candidates for potential applications such as water-oil separation, antibacterial properties, etc.