Mechanofluorochromism and self-recovery of alkylsilylpyrene-1-carboxamides

A family of (alkylsilyl)pyrene-1-carboxamides exhibits similar mechanofluorochromic responses upon grinding. However, their spontaneous fluorescence recovery processes are distinct despite their similarity in chemical structures and crystal packings. Fluorescence spectroscopy, crystallography, and nanomechanical tests revealed that the chromic direction is dominated by the packing motif, while the fluorescence recovery is driven by the intermolecular interactions and the reversibility of deformation. The stimuli-responsive properties of mechanofluorochromic pyrene derivatives, including spontaneous solid-state recovery processes, are elucidated through crystallography, spectroscopy, and nanomechanics.