The effect of halo-substituents on physical properties based on 1,3,5-triarylbenzenes: Synthesis, crystal structure and Hirshfeld surface

Abstract

A set of 1,3,5-triarylbenzenes with the formula of C24H15X3 (X = F (1), Cl (2), Br (3) and I (4)) have been prepared through the cyclotrimerization of the substituted-acetophenones in the presence of para-toluenesulfonic acid (p-TSA). The maximal emission peaks of compounds 1–4 were found at 358, 361, 363 and 374 nm in the solid state, respectively, revealing that the luminescent properties were tuned by the halo-substituent groups. The title compounds were characterized by FT-IR, UV–Vis, elemental analysis (EA) and single-crystal X-ray diffraction. There exist the hydrogen bonds and packing interactions among aromatic rings. Among these compounds, the I-substituent triarylphenyl compound displays the best thermal stabilities. The maximal absorbance peaks, the emission bands, the cell volume, and the decomposition temperature increase with the substituent groups changing from fluorine to iodine. Hirshfeld surface analysis reveals that the order of X···C close contacts are consistent with that of the luminescent maxima.