Morphology control on fluorescent metallacycle-cored supramolecular polymers

Regulation of the morphology of supramolecular polymers is a challenging task although the morphology of supramolecular polymers plays an important role in their properties and functions. Here, we report a simple and efficient method to control the morphologies of metallacycle-cored supramolecular polymers. An allyl-functionalized hexagonal metallacycle is cross-linked by poly(ethylene glycol) (PEG) dithiol to form metallacycle-cored supramolecular polymers. The morphologies of the supramolecular polymers can be finely regulated by the length of PEG as well as the solvent. In methanol, the polymers form rod-like structures with shorter PEG chains, which gradually change into sheets as the chain length is increased. In tetrahydrofuran, thin films are observed using short linkers, which gradually transform into vesicles and nanorings when the length of PEG is increased. This study not only provides a convenient method for the preparation of fluorescent metallacycle-cored supramolecular polymers via the thiol–ene reaction, but also reveals the influence of the length of the linker and the solvent on their morphology, which will pave a way for the preparation of supramolecular polymers with the desired morphology for diverse applications.