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 CHCl3 as inclusion solvent.