Homoleptic Silver-Rich Trimetallic M 20 Nanocluster.

Two silver-rich M 20 alloy nanoclusters (NCs), [Cu 3.5 Ag 16.5 {S 2 P(O n Pr) 2 } 12 ] ( 1 ) and [Cu 2.5 AuAg 16.5 {S 2 P(O n Pr) 2 } 12 ] ( 2 ), were synthesized and fully characterized by electrospray ionization mass spectrometry, NMR spectroscopy, and X-ray crystallography. Cluster 2 , the first structurally characterized trimetallic M 20 NC, was produced by doping one Au atom into a bimetallic M 20 NC. Structural analyses showed the preferred positions of Group 11 metals in the yielded M 20 NCs. Their antioxidation ability has been investigated, and the time-dependent UV-vis spectrum shows that the presence of Cu I atoms in structures 1 and 2 can improve the antioxidant ability.