Platinum Metallacycle-Based Molecular Recognition: Establishment and Application in Spontaneous Formation of a [2]Rotaxane with Light-Harvesting Property

Macrocyclic molecule-based host-guest systems, which provide contributions for the design and construction of functional supramolecular structures, have gained increasing attention in recent years. In particular, platinum(II) metallacycle-based host-guest systems provide opportunities for chemical scientists to prepare novel materials with various functions and structures due to the well-defined shapes and cavity sizes of platinum(II) metallacycles. However, the research on platinum(II) metallacycle-based host-guest systems has been given little attention. In this article, we demonstrate the host-guest complexation between a platinum(II) metallacycle and a polycyclic aromatic hydrocarbon molecule, naphthalene. Taking advantage of metallacycle-based host-guest interactions and the dynamic property of reversible Pt coordination bonds, a [2]rotaxane is efficiently prepared by employing a template-directed clipping procedure. The [2]rotaxane is further applied to the fabrication of an efficient light-harvesting system with multi-step energy transfer process. This work comprises an important supplement to macrocycle-based host-guest systems and demonstrates a strategy for efficient production of well-defined mechanically interlocked molecules with practical values.