Concentration dependent supramolecular interconversions of triptycene-based cubic, prismatic, and tetrahedral structures

The quantitative, single step, self-assembly of a shape-persistent, three-dimensional C3v-symmetric, triptycene-based tris-terpyridinyl ligand initially gives a platonic-based cubic architecture, which was unequivocally characterized by 1D and 2D NMR spectroscopy, mass spectrometry, and single crystal X-ray structural analysis. The unique metal-ligand binding properties of the Cd2+ analogue of this construct give rise to a concentration-dependent dynamic equilibrium between cube, prism, and tetrahedron-shaped architectures. Dilution transforms this cube into two identical tetrahedra through a stable prism-shaped intermediate; increasing the concentration reverses the process.