Mechanically Robust Supramolecular Fluorescent Materials Enabled by Metallacyclic Cross-Linker Engineering

Metallacycles/cages have emerged as promising supramolecular cross-linkers for fabricating high-performance supramolecular polymer networks (SPNs). However, their comprehensive benefits in simultaneously boosting mechanical performance and embedding diverse functionalities into polymer networks are yet to be fully explored. This gap underscores the challenge in developing metallacycle/cage-cross-linked SPNs encapsulating these attributes. Herein, we design a rhombic metallacycle-based supramolecular cross-linker to prepare a class of mechanically robust SPNs with unique photophysical properties. Rigid and stable metallacyclic frameworks function as multivalent cross-links and reinforcing components to enhance the mechanical performance. Besides, the modular self-assembly of metallacycle cross-linkers rendered them as versatile integrated platforms. Tetraphenylethylene-based rhombic cores of metallacycles possessed conformationally sensitive emission, which endowed SPNs with smart fluorescent responsiveness toward mechanical force. Terminal groups of metallacycles could establish dynamic quadruple H-bonding, thereby implanting energy-dissipating, self-healing, and reprocessable abilities for resultant SPNs. Our work opens new avenues for the molecular design of mechanically robust supramolecular materials with diverse smart functions.