Supramolecular G-Quadruplex Templating Enables Controlled Growth of Amorphous Coordination Polymer Nanodots for Photothermal CO2 Cycloaddition

Abstract

Amorphous coordination polymers offer distinct advantages over crystalline frameworks owing to their structural flexibility, high density of accessible coordination sites, and defect tolerance. Yet precise control over their nanoscale growth and dispersion remains a fundamental challenge. Herein, we report a biomolecule-driven supramolecular templating strategy for the generation of amorphous coordination polymer nanodot-embedded hydrogel. A guanosine monophosphate-based G-quadruplex supramolecular architecture, co-assembled with gallic acid, serves as an active template that spatially confines metal–polyphenol coordination. Upon Fe3+ incorporation, this supramolecular scaffold directs the formation of ultrasmall, uniformly dispersed coordination polymer nanodots, in contrast to the uncontrolled aggregation observed in non-templated systems. Spectroscopic and electrochemical analyses reveal that supramolecular confinement stabilizes mixed-valence Fe2+/Fe3+ species and enhances ligand-to-metal charge transfer, imparting efficient photothermal conversion under visible-light irradiation. As a proof-of-concept, the resulting hybrid material is shown to be an effective photothermal catalyst for solvent-free cycloaddition of CO2 to epoxides under ambient pressure, delivering cyclic carbonates with high efficiency. This work establishes G-quadruplex assembly as a versatile platform for regulating size-controlled growth of coordination polymers and highlights the functional advantages of biomolecular confinement for sustainable catalytic transformations.