Interdependence between nanoclusters AuAg and AuAg.

Whole series of nanoparticles have now been reported, but probing the competing or coexisting effects in their synthesis and growth remains challenging. Here, we report a bi-nanocluster system comprising two ultra-small, atomically precise nanoclusters, AuAg(SR) and AuAg(SR)(Dppm) (SR = cyclohexyl mercaptan, Dppm = bis(diphenylphosphino)-methane). The mechanism by which these two nanoclusters coexist is elucidated, and found to entail formation of the unstable AuAg(SR), followed by its partial conversion to AuAg(SR)(Dppm) in the presence of di-phosphorus ligands, and an interdependent bi-nanocluster system is established, wherein the two oppositely charged nanoclusters protect each other from decomposition. AuAg(SR) and AuAg(SR)(Dppm) are fully characterized by single crystal X-ray diffraction (SC-XRD) analysis - it is found that their co-crystallization results in single crystals comprising equimolar amounts of each. The findings highlight the interdependent relationship between two individual nanoclusters, which paves the way for new perspectives on nanocluster formation and stability.