Semi-Rigid Molecular-Clip-Based Molecular Crystal Gearshift

A new
version of molecular clip, with a semi-rigid symmetrical
crab-type architecture and flexible cavity size, has been successfully
designed and synthesized via a one-pot Friedel–Crafts alkylation
reaction. The X-ray single-crystal diffraction data provide a simple
and intuitive explanation, not only for its well-preorganized and
regulated conformation but also for its selective and tunable guest-binding
capability. For the first time, the newly designed molecular clip
was demonstrated to be not only a controllable variable-speed nonporous
adsorption material in solution iodine capture, but also capable of
on–off switching in volatile iodine capture. The presented
new concept of molecular crystal gearshift directly from the molecular
clip crystals represents an important advance in the development of
synthetic receptor chemistry, which will exert a significant influence
on small-molecule crystallography.