Alkynyl-Protected Bimetallic Nanoclusters with a Hybrid Mackay Icosahedral Ag Cu Cl Kernel and an Octahedral Ag Cu Kernel.

A facile strategy that directly reduces alkynyl-silver precursors and copper salts for the synthesis of bimetallic nanoclusters using the weak reducing agent Ph SiH is demonstrated. Two alkynyl-protected concentric-shell nanoclusters, (Ph P) [Ag Cu (C≡CR) ] and (Ph P) [Ag Cu Cl(C≡CR) ] (Ag Cu and Ag Cu Cl, 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 Ag Cu Cl, which is icosahedral M Cl instead of M . 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.