Novel helical assembly of a Pt(II) phenylbipyridine complex directed by metal-metal interaction and aggregation-induced circularly polarized emission.

Pt(ii) phenylbipyridine complexes possessing bis(phenylisoxazolyl)phenylacetylene ligands self-assembled to form stacked aggregates via Pt-Pt, π-π stacking, and dipole-dipole interactions. The assembled structures were influenced by the solvent properties. Non-helical assemblies found in chloroform displayed metal-metal-to-ligand charge transfer absorption and emission, whereas helical assemblies formed in toluene showed aggregation-induced enhancement of emission and aggregation-induced circularly polarized luminescence. The rates of the association and dissociation of the assemblies were significantly reduced in toluene, and the non-helical structures formed in chloroform were surprisingly memorized.