Adjusting the Architecture of Heptagonal Metallo‐Macrocycles by Embedding Metal Nodes into the Backbone

Coordination‐driven self‐assembly has been extensively employed for the bottom‐up construction of discrete metallo‐macrocycles. However, the prevalent use of benzene ring as the backbone limits the formation of large metallo‐macrocycles with more than six edges. Herein, by embedding metal nodes into the ligand backbone, we successfully regulated the ligand arm angle and assembled two giant heptagonal metallo‐macrocycles with precise control. The angle between two arms at position 4 of central terpyridine (tpy) extended after the complexation with metal ions, leading to the ring expansion of the metallo‐macrocycle. The assembled structures were straightforwardly identified through multi‐dimensional NMR (1H, COSY, NOESY), multidimensional mass spectrometry analysis (ESI‐MS and TWIM‐MS), transmission electron microscopy (TEM), as well as scanning tunneling microscopy (STM). In addition, the catalytic performances of metallo‐macrocycles in the oxidation of thioanisole were studied and both supramolecules exhibited good conversion rate. Furthermore, fiber‐like nanostructures were observed from single‐molecule heptagons by hierarchical self‐assembly.