Applications of self-assembled one-bilayer nanofilms based on hydroxyl-containing tetraphenylethene derivative's nanoaggregates as chemosensors to volatile of solid nitroaromatics

An aggregation-induced emission (AIE)-active chromophore 1,2-bis[4-(3-hydroxyphenyl)phenyl]-1,2-diphenylethene (TPE-2PhOH) was synthesized from 1,2-bis[4-bromophenyl]-1,2-diphenylethene (TPE-2Br) and 3-hydroxylphenylboronic acid via Suzuki coupling reaction. TPE-2PhOH nanoaggregates can be obtained from the nonsolvent-induced aggregation process. By alternately depositing 4,4′-biphenyldiazonium (BPD) salts and TPE-2PhOH nanoaggregates, layer-by-layer self-assembled films based on hydrogen-bonding interactions were successfully fabricated onto modified quartz slides. A more stable film was further prepared by subsequent decomposition of diazonium group (-N ₂ ⁺) under irradiation of UV light, which induces the conversation of the hydrogen-bond interaction between the hydroxyl groups on the surface of TPE-2PhOH nanoaggregates and diazonium groups into covalent bonds. The covalently linked self-assembled film exhibited highly fluorescence quenching sensitivity towards volatile of solid nitroanilines (2-nitroaniline (2-NA), 3-nitroaniline (3-NA) and 4-nitroaniline (4-NA)) and 2,4,6-trinitrotoluene (TNT) at normal atmospheric temperature and pressure. This strategy can provide a platform for developing highly sensitive and efficient chemosensors for harmful compounds and warfare explosives.