A Double-Walled Hexagonal Supermolecule Assembled by Guest Binding

The transition metal−ligand interaction has been one of the most powerful tools to construct various sophisticated supermolecules such as macrocycles1,2 and cages,1,3 owing to its strength and directionality. We recently described that discrete mono- and dinuclear macrocycles could be spontaneously assembled from a mixture of osmium tetroxide, olefin, and bispyridyl ligand.4 In this assembling motif, the octahedral coordination center is generated in situ during the assembly process, unlike most other systems which require extra steps for the preparation of the metal center with the desired geometry and properties. Furthermore, the macrocycles are electrically neutral so that molecular recognition based on hydrogen bonds can be studied without interference by otherwise existing counterions. Herein we report the first example of double-walled hexanuclear hexagon formed by spontaneous reorganization of osmate ester-based macrocycles in the presence of naphthalene-2,6-diol.