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. We report a platinum(II) metallacycle‐based host–guest system and its application in efficient construction of a [2]rotaxane with sequential light‐harvesting property.