Formation of an Alkynyl-Protected Ag112 Silver Nanocluster as Promoted by Chloride Released In Situ from CH2 Cl2.

By directly reducing alkynyl-silver precursors, we successfully obtained a large alkynyl-protected silver nanocluster, (C7 H17 ClN)3 [Ag112 Cl6 (C≡CAr)51 ], which is hitherto the largest structurally characterized silver nanocluster in the alkynyl family. The cluster exhibits four concentric core-shell structures (Ag13 @Ag42 @Ag48 @Ag9 ), and four types of alkynyl-silver binding modes are observed. Chloride was found to be critical for the stabilization and formation of the silver nanocluster. The release of chloride ions in situ from CH2 Cl2 solvent has been confirmed by mass spectrometry. This study suggests that the combination of alkynyl and halide ligands will pave a new way for the synthesis of large silver nanoclusters.