A new silver–thiolate nanocluster synthesized utilizing pure-inorganic polyoxoniobate as a starting template and its variable-temperature fluorescence properties†

In the past, the synthesis of polyoxometalate (POM)-templated silver nanoclusters typically relied on the use of organic salts of POMs as starting templates, thereby limiting the solvent selectivity in the synthesis. The utilization of pure-inorganic POMs as starting templates in developing novel POM-templated silver nanoclusters has been neglected. Herein, we have used pure-inorganic polyoxoniobates as a starting template to synthesize a new silver nanocluster H₄[Nb₆O₁₉@Ag₄₀(ⁱPrS)₂₈S₄] (Ag₄₀) (ⁱPrS = isopropylthiolate). Single-crystal X-ray diffraction analysis showed that the silver nanocluster exhibits a remarkable core–shell structure featuring a Lindqvist-type [Nb₆O₁₉]⁸⁻ polyanion as a template, surrounded by 40-nucleated silver ions as the metal shell and capped by ⁱPrS⁻ ligands. Interestingly, the silver nanocluster exhibits significant fluorescence properties at low temperatures, demonstrating temperature-dependent fluorescence, making it a potential candidate for temperature sensing. This work provides a new strategy for new POM-templated silver nanoclusters by using pure-inorganic POMs as starting templates. It also offers new insights into the anionic template method for synthesizing silver nanoclusters.