Sensitive mechanofluorochromism based on conversion of paired and unpaired enantiomer packing modes

Racemic Me-THP-2Br can form three fluorescent crystalline polymorphs (PC, BC and CC) and an amorphous state (AS), which are packed in enantiomer-paired (RS-) or -unpaired (RR/SS-) mode, and exhibit sensitive reversible mechanofluorochromism (65 nm) and excellent rewritable characteristics via conversion between the RS- and RR/SS-packing modes.391