Fluorophore dyes based on 9-thienylanthracene: AIEE behaviors, performance in solid state, and bioimaging in living cells

Abstract

Four new 9-thienylanthracene fluorescent dyes (TAs) bearing 1-methylindole/triphenylamine moieties were successfully synthesized. They all displayed typical aggregation-induced emission enhancement (AIEE) features with bright and varying aggregative-state emission involving multiple fluorescence colors containing cyan, green, and jacinth. Meanwhile, their solid state fluorescence could be effectively switched by mechanical grinding and dichloromethane fuming except for TPATA-Py12. Specifically, ITA, TPATA and ITA-Py12 showed reversible high contrast mechanofluorochromic (MFC) behaviors involving distinct fluorescent color changes from cyan/yellow to green/red. Notably, these TA dyes displayed excellent biocompatibility and have been successfully realized in living cell imaging. Particularly, ITA-Py12 and TPATA-Py12 can steadily immobilize in the mitochondria of HeLa cells by strong hydrophobic interaction between the C12-alkyl chain and lipid bilayer, resulting in high specificity mitochondrial staining. These good properties of them could provide a reference for the design and development of multi-functional AIEE dyes based on TA-skeleton.