Unlocking the Potential of an Atom-Precise Ag₁₂ Cluster Assembled Material as a Highly Efficient SERS Sensor for the Detection of Hg²⁺ Ions

We outline an approach for the first time to employ a Ag(I) cluster-assembled material as a surface-enhanced Raman scattering (SERS) sensor for the detection of Hg 2+ ions. Our research focuses on the design of [Ag 12 (S t Bu) 6 (CF 3 COO) 6 (TPSBF) 6 ] n ( TUS 4 ) (TPSBF = 2,2′,7,7′-tetra(pyridin-4-yl)-9,9′-spirobi(fluorene)), which is constructed by stitching Ag 12 cluster nodes in a three-dimensional manner using tetradentate spirobifluorene linkers. The structural arrangement of TUS 4 plays a crucial role in its optical characteristics, distinguishing it from grind samples and ensuring its suitability in its crystalline state. Credited with its exceptional chemical stability within the intricate structural architecture, TUS 4 is utilized as a sensing probe in SERS for precise detection of Hg 2+ ions under controlled conditions. Due to its atomic specificity and distinctive structural architecture, TUS 4 attains an unprecedentedly low detection limit, 0.07 pg mL –1, achieved through the formation of the Ag–Hg amalgam.