Complex Arrangement of Orthogonal Nanoscale Columns via a Supramolecular Orientational Memory Effect.

Memory effects, including shape, chirality, and liquid-crystallinity, have enabled macroscopic materials with novel functions. However, the generation of complex supramolecular nanosystems via memory effects has not yet been investigated. Here, we report a cyclotriveratrylene-crown (CTV) compound that self-assembles into supramolecular columns and spheres forming, respectively, hexagonal and cubic mesophases. Upon transition from one phase to the other, an epitaxial relationship holds, via an unprecedented supramolecular orientational memory effect. Specifically, the molecular orientation and columnar character of supramolecular packing is preserved in the cubic phase, providing an otherwise inaccessible structure comprising orthogonally oriented domains of supramolecular columns. The continuous columnar character of tetrahedrally distorted supramolecular spheres self-organized from the CTV derivative in the faces of the Pm3̅n lattice is the basis of this supramolecular orientational memory, which holds throughout cycling in temperature between the two phases. This concept is expected to be general for other combinations of periodic and quasiperiodic arrays generated from supramolecular spheres upon transition to supramolecular columns.