Reacting the unreactive: A toolbox of low-temperature solution-mediated reactions for the facile interconversion of nanocrystalline intermetallic compounds

Metallurgical materials, including intermetallic compounds, are notoriously inert toward low-temperature reactivity. However, as nanocrystals, their reactivity is significantly enhanced. Here we show that intermetallic PtSn and AuCu nanocrystals can be converted, in solution at low temperatures, into derivative intermetallics. For example, PtSn can be converted into PtSn₂ and Pt₃Sn by reaction with SnCl₂ and K₂PtCl₆, respectively. The reactions are also reversible, for example, the sequences PtSn → PtSn₂ → PtSn and PtSn → Pt₃Sn → PtSn are all readily achievable. The strategy also allows nanocrystalline AuCu to be successfully converted into AuCu₃ via reaction with Cu(C₂H₃O₂)₂·H₂O, suggesting that this approach may be general.