Reversible mechanical protection: building a 3D suit around a T-shaped benzimidazole axle

The T-shaped benzimidazolium/crown ether recognition motif was used to prepare suit[1]anes. These novel mechanically interlocked molecules (MIMs) were fully characterized by H-1 and C-13 NMR spectroscopy, single-crystal X-ray diffraction, UV-vis absorption and fluorescence spectroscopy. By conversion to a suit [1] ane, a simple benzimidazole was shown to be protected from deprotonation by strong base. Moreover, it was demonstrated that this unique three-dimensional encapsulation can be made reversible, thus introducing the concept of reversible mechanical protection; a protecting methodology that may have potential applications in synthetic organic chemistry and the design of molecular machinery.