Controlled Synthesis of Diphosphine-Protected Gold Cluster Cations Using Magnetron Sputtering Method

We demonstrated, for the first time, atomically precise synthesis of gold cluster cations by magnetron sputtering of a gold target onto a polyethylene glycol (PEG) solution of 1,3-bis(diphenylphosphino)propane (Ph2PCH2CH2CH2PPh2, dppp). UV-vis absorption spectroscopy and electrospray ionization mass spectrometry revealed the formation of cationic species, such as [Au(dppp)(n)](+) (n = 1, 2), [Au-2(dppp)(n)](2+) (n = 3, 4), [Au-6(dppp)(n)](2+) (n = 3, 4), and [Au-11(dppp)(5)](3+). The formation of [Au(dppp)(2)](+) was ascribed to ionization of Au(dppp)(2) by the reaction with PEG, based on its low ionization energy, theoretically predicted, mass spectrometric detection of deprotonated anions of PEG. We proposed that [Au(dppp)(2)](+) cations thus formed are involved as key components in the formation of the cluster cations.

Automated summary

In this study, we successfully demonstrated the atomically precise synthesis of gold cluster cations by magnetron sputtering onto a PEG solution of dppp. The formation of cationic species was confirmed through UV-vis absorption spectroscopy and electrospray ionization mass spectrometry, and the involvement of [Au(dppp)(2)](+) cations as key components in cluster formation was proposed based on experimental observations.