The bis(p-sulfonatophenyl)phenylphosphine-assisted synthesis and phase transfer of ultrafine gold nanoclusters

► We develop a facile route to prepare ultrafine Au nanoclusters (NCs) at room temperature. ► The Au NCs thus prepared are dominated by the {200} facets. ► We use bis(p-sulfonatophenyl)phenylphosphine (BSPP) to stabilize the Au NCs and to facilitate the transfer of Au NCs from aqueous to an organic medium. ► The Au NCs after transfer can maintain their original size and morphology. ► The Au NCs transferred into toluene are used as seeds for the formation of core-shell Au@Ag2S nanocrystals.