Reticular construction of a two-dimensional Ag12 cluster-assembled material for rapid and selective luminescent sensing of antibiotics in aqueous media

Abstract

Silver cluster-assembled materials (SCAMs) represent a promising class of luminescent solids, uniting atomically precise metal core architectures with crystalline framework design for tunable optical performance. Despite offering enhanced structural integrity over discrete silver nanoclusters, their broader application—particularly in aqueous-phase sensing—remains constrained by limited chemical and structural stability. Herein, we report TUS 8, a two-dimensional SCAM constructed from dodecanuclear Ag₁₂ nodes and 1,1′-sulfonyldiimidazole (SDI) linkers. Single-crystal X-ray diffraction reveals a (2,4)-connected network in the P2₁/c space group featuring slightly distorted, hollow cuboctahedral Ag₁₂ cores capped by μ₄-tert-butylthiolates and μ₂-trifluoroacetates. These layers stack via noncovalent interactions, forming a chemically robust porous architecture. TUS 8 exhibits intense ultraviolet absorption (λ_ex = 215 nm) and strong aqueous photoluminescence emission at 344 nm, with a mono-exponential lifetime of 4.62 ns and an absolute quantum yield of 26.3%, among the highest reported for silver-based MOFs in water. The rigid framework and Ag⋯Ag interactions suppress non-radiative decay to enhance luminescence performance in aqueous media, while the material's retention of high crystallinity after immersion in various solvents underscores its chemical robustness. Leveraging these features, TUS 8 functions as a recyclable luminescent sensor for antibiotic detection in water. Distinct PL responses are observed for nitrofurans, nitroimidazoles, and chloramphenicol, with quenching constants up to 2.4 × 10³ M⁻¹ and detection limits as low as 311 μM. This study highlights the potential of cluster-based reticular design for creating durable, water-stable, and highly emissive sensing platforms.