Total structural determination of [AuAg(Dppm)(SR)] comprising an open icosahedral AuAg core with six free valence electrons.

Herein, we report the first silver-rich nanocluster containing an open icosahedral Au1Ag12 core. This nanocluster is determined to be [Au1Ag24(Dppm)3(SR)17]2+ (where Dppm is short for bis-(diphenylphosphino)methane and SR is short for cyclohexyl mercaptan) by single-crystal X-ray diffraction and electrospray ionization mass spectrometry (ESI-MS). The Au1Ag24 consists of an open icosahedral Au1Ag12, which contains six free valence electrons surrounded by a big ring motif Ag12(Dppm)3(SR)15 and two SR groups. Density Functional Theory (DFT) provided insight into the relationship between the structure and its performance.