X-ray Crystal Structure of Au38-xAgx(SCH2CH2Ph)24 Alloy Nanomolecules

Herein, we report the X-ray crystallographic structure of a 38-metal atom Au-Ag alloy nanomoleafle. The structure of monometallic Au-38(SR)(24) consists of 2 central Au atoms and 21 Au atoms forming a bi-icosahedral core protected by 6 dimeric and 3 monomeric units. In Au38-xAgx(SR)(24),where x ranges from 1 to S, the silver atoms are selectively incorporated into the Aun bi-icosahedral core. Within the Au-21 core, the silver atoms preferentially occupy nine selected locations: (a) the two vertex edges, three atoms on each edge and six atoms total, and (b) the middle face-shared three-atom ring, adding to a total of nine locations. X-ray crystallography yielded a composition of Au34.04Ag3.96(SCH2CH2Ph)(24). The crystal structure of the alloy nanomolecule can be described in terms of shells as Au-2@Au17.04Ag3.(96)@ 6X [SR-Au-SR-Au-SR] 3X [SR-Au-SR-].