Deciphering synergetic core-shell transformation from [Mo6O22@Ag44] to [Mo8O28@Ag50]

Abstract

The structural transformation of high-nuclearity silver clusters from one to another induced by specific stimuli is of scientific significance in terms of both cluster synthesis and reactivity. Herein, we report two silver-thiolate clusters, [Mo₆O₂₂@Ag₄₄] and [Mo₈O₂₈@Ag₅₀], which are templated by isopolymolybdates inside and covered by ⁱPrS⁻ and PhCOO⁻ ligands on the surfaces. Amazingly, the [Mo₈O₂₈@Ag₅₀] can be transformed from [Mo₆O₂₂@Ag₄₄] by adding PhCOOH which increases the degree of condensation of molybdates template from Mo₆O₂₂^8- to Mo₈O₂₈^8-, then enlarging the outer silver shell from Ag₄₄ to Ag₅₀. The evolution of solution species revealed by time-dependent electrospray ionization mass spectrometry (ESI-MS) suggests a breakage-growth-reassembly (BGR) transformation mechanism. These results not only provide a combined assembly strategy (anion-template + induced transformation) for the synthesis of silver-thiolate clusters but also help us to better understand the complex transformation process underpinning the assembly system.