AIE-active dyes based on Tröger's base: Synthesis and mechanochromic luminescence

Three fluorescent dyes (DI-TB, ICZ-TB and ITPA-TB) were synthesized based on 1,3-indindanedione substituted Tröger's base (TB). All the dyes exhibited AIE properties in the mixed system of chloroform and n-hexane. The compounds showed reversible MCL properties with obvious fluorescence changes, which were confirmed by XRD and DSC. The fluorescence of ITPA-TB showed high contrast (68 nm) before and after grinding, and the fluorescence changed from yellow (546 nm) to red (614 nm). In addition, the three solid compounds showed good thermal stability by thermogravimetric analysis. The TB dyes further opened up new ideas for the development of TB-based mechanochromic luminescent materials.