Photoresponsive Toroidal Nanostructure Formed by Self-Assembly of Azobenzene-Functionalized Tris(phenylisoxazolyl)benzene

The self-assembly of tris(phenylisoxazolyl)benzene 1b with photo chemically addressable azobenzene moieties produced toroidal nanostructures, the formation and dissociation of which were reversibly regulated upon photoirradiation. 1b displayed a mesogenic behavior. In the solution, the stacked assemblies along with their C-3 axes were formed. In the mesophase, two molecules of 1b most likely adopted the antiparallel arrangement to stabilize the columnar organization. This assembling behavior most likely triggered the development of the supramolecular toroidal nanostructures.