Self-Sorting of Rosette-Forming Naphthalene Barbiturates into Distinct Toroidal Assemblies

A unique narcissistic self-sorting system is composed of two structurally similar mono- and bisnaphthalene-based supramolecular monomers. Upon cooling the pure mono- and bisnaphthalene monomers in a nonpolar solvent, toroidal and helicoidally elongated supramolecular polymers were obtained, respectively, through the nucleation-elongation mechanism. When a 1 : 1 mixture of these monomers was similarly cooled, we obtained self-sorted mixtures of smaller and larger toroidal supramolecular polymers with diameters of 15 and 26 nm, respectively. Absorption spectroscopic studies revealed that the mononaphthalene monomers prevents the bisnaphthalene monomers from forming nuclei, leading to a less cooperative polymerization process.