Development of precise transformation reactions of goldsuperatoms initiated by hydride doping

摘要

Ligand-protected gold-based clusters [AuxMyLz]~n (M = Group IX,X,and XIelements;L = thiolates,alkynyls,phosphines,N-heterocyclic carbenes,and halides) can beviewed as chemically-modified gold superatoms.They provide an ideal platform toinvestigate the structure-property correlation in nanoscale materials.Motivated by aninteresting report that the hydrogen atom in bare gold clusters mimics a gold atom,we haveinvestigated the interaction of hydride (H-) with phosphine-protected oblate clusters,[MAu8(PPh3)8]~(2+) (MAu8;M = Au~+,Pd,Pt) as the prototypical 6e superatoms.In situelectrospray ionization mass spectrometry and NMR spectroscopy revealed that addition ofBH_4~-to MAu8 quickly afforded [HMAu8(PPh3)8]~+ (HMAu8) almost quantitatively,and thatthe H-was bound to the central M atom.DFT calculation suggested that the (HM@Au8)~+superatomic core has a quasi-spherical motif with the closed electron configuration of(1S)~2(1P)~6.These results suggested that the H~-in (HM@Au8) superatoms behaves as adopant rather than as an anionic ligand.