Serendipitous Assembly of Chiral Face-Rotating Molecular Boxes Directed by Non-Covalent Templation

A serendipitous outcome in the mandelic acid-mediated imine condensation of a tetraphenylethene-derived tetraaldehyde and tris(2-aminoethyl)amine led to [2 + 4] face-rotating molecular boxes, rather than the expected [6 + 8] cubic cages. The resulting D₂-symmetric assemblies feature two homochiral tetraphenylethene facial units and four unreacted amine handles. Mandelic acid engages in cooperative hydrogen bonding, steric effect and C-H···π interactions that steer the assembly pathway and supramolecular chirality. NMR, ECD, and X-ray analyses confirm the formation of a pair of diastereomeric supramolecular complexes exhibiting distinct optical activity in solution.