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

Abstract

AbstractCoordination‐driven self‐assembly has been extensively employed for the bottom‐up construction of discrete metallo‐macrocycles. However, the prevalent use of benzene rings 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 the central terpyridine (tpy) extended after complexation with metal ions, leading to ring expansion of the metallo‐macrocycle. The assembled structures were straightforwardly identified through multi‐dimensional NMR spectroscopy (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, with both supramolecules exhibiting good conversion rates. Furthermore, fiber‐like nanostructures were observed from single‐molecule heptagons by hierarchical self‐assembly.