'Passivated Precursor' Approach to All-Alkynyl-Protected Gold Nanoclusters and Total Structure Determination of Au₁₃₀

A 'passivated precursor' approach is developed for the efficient synthesis and isolation of all-alkynyl-protected gold nanoclusters. Direct reduction of dpa-passivated precursor Au-dpa (Hdpa=2,2'-dipyridylamine) in one-pot under ambient conditions gives a series of clusters including Au₂₂(C≡CR)₁₈ (R=-C₆H₄-2-F), Au₃₆(C≡CR)₂₄, Au₄₄(C≡CR)₂₈, Au₁₃₀(C≡CR)₅₀, and Au₁₄₄(C≡CR)₆₀. These clusters can be well separated via column chromatography. The overall isolation yield of this series of clusters is 40 % (based on gold), which is much improved in comparison with previous approaches. It is notable that the molecular structure of the giant cluster Au₁₃₀(C≡CR)₅₀ is revealed, which presents important information for understanding the structure of the mysterious Au₁₃₀ nanoclusters. Theoretical calculations indicated Au₁₃₀(C≡CR)₅₀ has a smaller HOMO-LUMO gap than Au₁₃₀(S-C₆H₄-4-CH₃)₅₀. This facile and reliable synthetic approach will greatly accelerate further studies on all-alkynyl-protected gold nanoclusters.