Vortex-Flow-Directed Chiral Macroscopic Ordering of Platelet Nanostructures Formed via the Supramolecular Assembly of Platinum Complexes with Bis(phenylisoxazolyl)benzene

To understand the vortex flow-directed circular dichroism (CD) effect observed in homogeneous solutions containing supramolecular structures, the macroscopic order formed by supramolecular structures oriented within a flow must be visualized. In this study, a bis(phenylisoxazolyl)benzene-attached platinum complex was found to self-assemble to form uniform anisotropic platelet nanostructures that are oriented within a flow, thereby generating a chiral macroscopic order that is responsible for CD and linear dichroism (LD) effects only in the vortex flow regime. Cooperative self-assembly of a bis(phenylisoxazolyl)benzene-attached platinum complex via controlled supramolecular polymerization produced anisotropic platelet nanostructures with a narrow polydispersity index. The orientational order parameter of the nanostructures correlated with the flow velocity; thus, the nanostructures were oriented along the flow direction. Furthermore, the vortex flow of the dilute nanostructure solution broke the symmetry of the flow, thereby generating a chiral macroscopic order. As a result, CD and LD effects were observed in the vortex flow regime of the dilute nanostructure solution. These results can be generalized to the formation of chiral macroscopic order in solutions containing anisotropic nanostructures.