The mystery of Ph3PS revealed in magic-size Ag–S cluster nucleation

Abstract

The synthesis of atomically precise semiconductors Ag–S clusters is a subject of intense research interest, yet the formation mechanism of such nanoclusters remains obscure due to their uncontrolled fast nucleation process in solution. Herein, we have investigated the reaction mechanism responsible for {Ag₃₂S₃} nucleation using UV, ESI-MS, NMR and SCXRD analyses. Triphenylphosphorus sulfide (PPh₃S) was surprisingly found to slow down the kinetic process of the cluster nucleation. Furthermore, a key precursor [Ag₂(Ph₃PS)₄]²⁺ was captured, which was attacked by Ag_n(CCBu^t)_m and traces of water to generate {Ag₃₂S₃}. This mechanism provides valuable new insights into the synthesis of inorganic magic-size clusters.