Mass Spectrometric Identification of Au68(SR)34 Molecular Gold Nanoclusters with 34-Electron Shell Closing

The molecular formula Au-68(SCH2CH2Ph)(34) has been assigned to the 14 kDa nanocluster using MALDI-TOF mass spectrometry. The 34-electron shell closing in a macroscopically obtained thiolated gold nanocluster is demonstrated. The Au-68 nanocluster is predicted to have a 49 atom Marks decahedral core with 19 inner core atoms and 30 outer atoms chelating with the staple motifs. The nanoclusters' predicted formulation is [Au](19.30)[Au(SR)(2)](11) [Au-2(SR)(3)](4).