Trimethylsilyl Group Assisted Stimuli Response: Self-Assembly of 1,3,6,8-Tetrakis((trimethysilyl)ethynyl)pyrene

Substitution
of 1,3,6,8-tetraethynylpyrene with sterically bulky trimethylsilyl
groups enabled four modes of molecular packing, two polymorphs (triclinic
system (Y-form) and “loose” crystal Colho (OK-form)), a ”rigid” liquid crystalline phase Colho (OC-form), and
an amorphous phase (OA-form), which emitted fluorescence at different wavelengths under UV light.
The four phases could be interconverted by physical stimuli such as
heating, grinding by mortar and pestle, and exposing to the vapor
of organic solvents.