三苯基膦：转换硫醇保护的纳米粒子成[Au25(PPh3)10(SR)5Cl2]2+

我们在此报道了一种未曾发现的有趣现象：尽管Au₂₃(SC₆H₁₁)₁₆]⁻、Au₂₄(SC₂H₄Ph)₂₀ (Ph:苯环)、Au₃₆(TBBT)₂₈ (TBBTH:对叔丁基苯硫酚)、Au₃₈(SC₂H₄Ph)₂₄、混合Au_x(SC₂H₄Ph)_y团簇及3 nm的金纳米粒子有不同的组成、结构、尺寸和保护性硫醇配体，但它们在三苯基膦(PPh₃)作用下，均能统一地经由亚稳的Au₁₁(PPh₃)₈Cl₂]²⁺最终转化为稳定的双二十面体Au₂₅(PPh₃)₁₀(SR)₅Cl₂]²⁺ (SR:硫醇配体)。换句话说，三苯基膦是这些硫醇保护的纳米粒子的统一转化器。然而，聚乙烯吡咯烷酮(PVP)/柠檬酸盐(Citrate)保护的金纳米粒子和Ag₂₅(SPhMe₂)₁₈]⁻ (Me:甲基)在同样的条件下，却不能转化为Au₂₅(PPh₃)₁₀(SR)₅Cl₂]²⁺或Ag₂₅(PPh₃)₁₀(SR)₅Cl₂]²⁺，暗示了硫醇保护的金纳米粒子具有与三苯基膦反应的独特性能。另外，我们考察了配体对双二十面体Au₂₅(PPh₃)₁₀(SR)₅Cl₂]²⁺团簇荧光性能的影响。

PPh3: Converts Thiolated Gold Nanoparticles to [Au25(PPh3)10(SR)5Cl2]2+

Research on gold nanoclusters is at the frontier of nanoscience and nanotechnology. The introduction of the first phosphine-protected gold nanocluster, Au₁₁(PPh₃)₇(SCN)₃ (where PPh₃ stands for triphenylphosphine and Ph stands for benzene), can be dated back to 1969. As research in the field progressed, many structures of phosphine-protected nanoclusters such as Au₅, Au₈, Au₁₃, and Au₃₉ were reported. However, the stability of these phosphine-protected nanoclusters was not satisfactory, which handicapped their research and application. In an attempt to find alternatives for phosphine-protected nanoclusters, thiolated gold nanoclusters have attracted extensive attention in recent years. So far, there has been great progress primarily owing to the development of wet-chemical synthesis techniques, among which the utilization of ligand-exchange has been proved to be very effective to synthesize thiolated gold nanoclusters. It can be easily understood that phosphine in gold nanoclusters can be exchanged with thiolate because the latter has stronger affinity for gold. However, we recently found that the reverse ligand-exchange, i.e., the exchange of thiolate with phosphine, can also take place. Some questions have naturally arisen: Is the reverse ligand-exchange only applicable to superatomic Au₂₅(SR)₁₈]⁻ (SR: thiolate) nanoclusters? Can it occur in other thiolated gold nanoclusters? If so, is this reverse ligand-exchange also dependent on the starting nanoclusters? These intriguing issues have inspired us to conduct this work.