Velcrands with snaps and their conformational control

A novel class of self-folding velcrands was prepared that dimerize through intermolecular forces. Solvophobic interactions on extended pi surfaces stabilize the dimer similar to velcrands, while eight hydrogen bonds act like snaps to hold the molecules together. The self-complementary array of hydrogen bonding sites were incorporated on the upper rim of a resorcinarene-based cavitand. A dramatic reorganization of shape and size of the internal cavity was manifested through changes in solvent polarity. Specifically, the equilibrium between the extended surface (D2d symmetry) and a deep cavity (C4v symmetry) could be manipulated in mixtures of aromatic solvents (or CDCl3) and [D6]DMSO. The switching of conformations and the dimerization motif are well-suited for the assembly of noncovalent polymeric materials.