Synthesis and luminescence properties of two silver cluster-assembled materials for selective Fe³⁺ sensing

Silver cluster-assembled materials (SCAMs) are emerging light-emitting materials with molecular-level structural designability and unique photophysical properties. Nevertheless, the widespread application scope of these materials is severely curtailed by their dissimilar structural architecture upon immersing in different solvent media. In this work, we report the designed synthesis of two unprecedented (4.6)-connected three-dimensional (3D) luminescent SCAMs, [Ag-12((SBu)-Bu-t)(6)(CF3COO)(6)(TPEPE)(6)](n) (denoted as TUS 1), TPEPE = 1,1,2,2-tetrakis(4-(pyridin-4-ylethynyl)phenyl)ethene and [Ag-12((SBu)-Bu-t)(6)(CF3COO)(6)(TPVPE)(6)](n) (denoted as TUS 2), TPVPE = 1,1,2,2-tetrakis(4-((E)-2-(pyridin-4-yl)vinyl)phenyl)ethene, composed of an Ag-12 cluster core connected by quadridentate pyridine linkers. Attributed to their exceptional fluorescence properties with absolute quantum yield (QY) up to 9.7% and excellent chemical stability in a wide range of solvent polarity, a highly sensitive assay for detecting Fe3+ in aqueous medium is developed with promising detection limits of 0.05 and 0.86 nM L-1 for TUS 1 and TUS 2 respectively, comparable to the standard. Furthermore, the competency of these materials to detect Fe3+ in real water samples reveals their potential application in environmental monitoring and assessment.