Jumping Crystals of Pyrene Tweezers: Crystal‐to‐Crystal Transition Involving π / π ‐to‐CH/ π Assembly Mode Switching

Crystals of pyrene tweezers 1 with interdigitating pyrenyl blades jump vigorously at around 160 °C. Single‐crystal X‐ray diffraction analysis before jumping revealed the presence of a “pyrene tetrad” in the crystal lattice, where four pyrenyl blades are π ‐stacked on top of each other. Upon heating the crystal to induce the jumping event, inner two pyrenyl blades in the “pyrene tetrad” probably rotate to switch off their π ‐stacking interaction with the neighboring outer pyrenyl blades and form new CH− π bonds. Different from reported salient crystals, our crystal jumps with the release of CHCl 3 as inclusion solvent.