Triphenylethylene benzimidazole derivatives with aggregation-induced emission (AIE) characteristics: An effect of the aryl linker and application in cell imaging

Three triphenylethylene benzimidazole derivatives TPT-BI, TPPT-BI and TPB-BI with aggregation-induced emission properties were synthesized, and the effect of connecting aromatic rings was studied. Among these TPT-based luminescent agents, TPT-BI showed the biggest red-shift, which may be due to the noncoplanar structure caused by thiophene as a connection ring. TPB-BI displayed the strongest fluorescence emission intensity and the longest lifetime, which may be due to the longest conjugate chain caused by two benzene rings as connection ring. Moreover, their solid-state fluorescence could be effectively adjusted through mechanical grinding and solvent fuming, and they all exhibited reversible mechanofluorochromic performance. Furthermore, these TPT-based luminescent agents showed low toxicity and biocompatibility, so they could be used as fluorescent dyes for cell imaging.