A synchronous nucleation and passivation strategy for controllable synthesis of Au36(PA)24: unveiling the formation process and the role of Au22(PA)18 intermediate

Despite the recent progress on controllable synthesis of alkynyl-protected Au nanoclusters, the effective synthetic means are very limited and the cluster formation process still remains puzzling. Here, we develop a novel synchronous nucleation and passivation strategy to fabricate Au 36 (PA) 24 (PA=phenylacetylenyl) nanoclusters with high yield. In Au 36 (PA) 24 formation process, Au 22 (PA) 18 as key intermediate was identified. Meanwhile, Au 22 (PA) 18 can be synthesized under a low amount of reductant, and by employing more reductants, Au 22 (PA) 18 can turn into Au 36 (PA) 24 eventually. Moreover, the structure evolution from Au 22 (PA) 18 to Au 36 (PA) 24 is proposed, where four Au 13 cuboctahedra can yield one Au 28 kernel. Finally, the ratiocination is verified by the good accordance between the predicted intermediate/product ratio and the experimental value. This study not only offers a novel synthetic strategy, but also sheds light on understanding the structural evolution process of alkynyl-protected Au nanoclusters at atomic level.