Synthesis and characterization of a β-ketoenamine COF Tp-BD(Me)2 at mild temperatures

Abstract

In this work, we investigated the morphology and crystallinity changes of a [Formula: see text]-ketoenamine COF, Tp-BD(Me) 2 (Tp=1,3,5-triformylphloroglucinol, BD(Me) 2 =3,3[Formula: see text]-dimethyl-[1,1[Formula: see text]-biphenyl]-4,4[Formula: see text]-diamine), with different reaction time and temperatures. Powder X-ray diffraction (PXRD) and Fourier-transform infrared (FTIR) spectra tests confirmed the synthesis of Tp-BD(Me) 2 , which has a specific [Formula: see text]-ketoenamine linkage and a probable eclipsed stacking mode. At a reaction temperature of 50[Formula: see text]C, the morphology of Tp-BD(Me) 2 underwent a progressive process of growing, extending and splitting. The band gaps of the Tp-BD(Me) 2 obtained with the reaction time of 18–24 h were calculated near 2.0 eV. The BET surface areas of the Tp-BD(Me) 2 were around 400–600 m 2 /g. It is not an optimal choice if the reaction temperature is below 50[Formula: see text]C, which could cause a low crystallinity and disordered morphology. However, slightly improving the reaction temperature to 60[Formula: see text]C is beneficial for generating high-crystallinity Tp-BD(Me) 2 .