Phthalimide Compounds Containing a Trifluoromethylphenyl Group and Electron-Donating Aryl Groups: Color-Tuning and Enhancement of Triboluminescence

Trifluoromethylphenyl-substituted
phthalimide derivatives favorably
form triboluminescence (TL) active noncentrosymmetric crystals. Oligothienyl-,
oligophenyl-, and naphthyl-substituted phthalimide derivatives were
successfully developed as a series of metal free TL compounds. X-ray
crystal structure analyses of bithienyl and naphthyl derivatives revealed
noncentrosymmetric layer structures in the same direction. Introduction
of suitable electron rich π-units such as thienyl groups enhances
their photoluminescence and TL characteristics, and the colors can
be also controlled in the visible region. A rigid naphthyl-substituted
imide derivative exhibits extremely high TL performance.