Coordination Mode Engineering of Silver Cages: From ACQ to AIE for Sequential Artificial Light Harvesting and...

Silver-(I)-based metallacages are gaining interest in supramolecular chemistry owing to their tunable properties and diverse applications. Herein, we report a sequential artificial light-harvesting system using a silver-based cage. Two metallacages were synthesized: one coordinated through nitrogen (MC ₁ , N-Ag-N) and the other through carbene carbon (MC ₂ , C-Ag-C), each with newly constructed aggregation-induced emissive (AIE-active) ligands. MC ₁ presents a flexible structure and exhibits AIE properties in the aggregate form, allowing for efficient three-stage sequential energy transfer from the cage (MC ₁ ) to eosin-Y (ESY), to sulforhodamine 101 (SR101), and finally to Cyanine-5-maleimide (Cy5). Notably, we can easily achieve bright white-light emission with a high quantum yield of 93%. In sharp contrast, MC ₂ with a rigid structure exhibits high fluorescence in the solution state, while significant fluorescence quenching occurs in its aggregated state, thereby prohibiting its application in light-harvesting systems. This work focuses on the crucial function of structural flexibility in silver-based metallacages in energy-transfer processes and promotes silver-based metallacages as promising new candidates for advanced sequential artificial light-harvesting.