The conventional synthetic methodology for atomically precise gold nanoclusters by using reduction in solution offers only the thermodynamically most stable nanoclusters. Herein, a solubility-driven isolation strategy is reported to access a metastable gold cluster. The cluster, with the composition of [Au9(PPh3)8]+ (1), displays an unusual, nearly perfect body-centered cubic (bcc) structure. As revealed by ESI-MS and UV/Vis measurements, the cluster is metastable in solution and converts to the well-known [Au11(PPh3)8Cl2]+ (2) within just 90 min. DFT calculations revealed that although both 1 and 2 are eight-electron superatoms, there is a driving force to convert 1 to 2 as shown by the increased cohesion and larger HOMO–LUMO energy gap of 2. The isolation and crystallization of the metastable gold cluster were achieved in a biphasic reaction system in which reduction of gold precursors and crystallization of 1 took place concurrently. This synthetic protocol represents a successful strategy for investigations of other metastable species in metal nanocluster chemistry.
|Number of pages||6|
|Journal||Chemistry - A European Journal|
|Publication status||Published - 8 Jul 2020|
Bibliographical noteFunding Information:
We thank the National Key R&D Program of China (2017YFA0207302) and the NSF of China (21890752, 21731005, 21721001) for financial support. The computational work by the University of Jyväskylä was supported by the Academy of Finland (grants 294217, 319208, 315549), and through H.H.’s Academy Professorship. H.H. acknowledges support from China's National Innovation and Intelligence Introduction Base visitor program. E.S. acknowledges the Emil Aaltonen Foundation for a PhD study grant. The computations were made at the CSC supercomputing center in Finland and as part of a PRACE project in the Barcelona Supercomputing Center.
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- body-centered cubic
- metastable compounds