Alkynyl‐Protected Bimetallic Nanoclusters with a Hybrid Mackay Icosahedral Ag42Cu12Cl Kernel and an Octahedral Ag22Cu12 Kernel.

A facile strategy that directly reduces alkynyl‐silver precursors and copper salts for the synthesis of bimetallic nanoclusters using the weak reducing agent Ph2SiH2 is demonstrated. Two alkynyl‐protected concentric‐shell nanoclusters, (Ph4P)2[Ag22Cu12(C≡CR)28] and (Ph4P)3[Ag42Cu12Cl(C≡CR)36] (Ag22Cu12 and Ag42Cu12Cl, R=bis(trifluoromethyl)phenyl), were successfully obtained and characterized by single‐crystal X‐ray diffraction and electro‐spray ionization mass spectrometry. For the first time, a hybrid 55‐atom two‐shell Mackay icosahedron was found in Ag42Cu12Cl, which is icosahedral M54Cl instead of M55. The incorporation of a chloride in the metal icosahedron contributes to the stability of the cluster from both electronic and geometric aspects. Alkynyl ligands show various binding‐modes including linear "RC≡C−Cu−C≡CR" staple motifs. [ABSTRACT FROM AUTHOR]