Selective formation of [Au(23)(SPh(t)Bu)(17)](0), [Au(26)Pd(SPh(t)Bu)(20)](0) and [Au(24)Pt(SC(2)H(4)Ph)(7)(SPh(t)Bu)(11)](0) by controlling ligand-exchange reaction

To use atomically precise metal nanoclusters (NCs) in various application fields, it is essential to establish size-selective synthesis methods for the metal NCs. Studies on thiolate (SR)-protected gold NCs (Au(n)(SR)(m) NCs) revealed that the atomically precise Au(n)(SR)(m) NC, which has a different chemical composition from the precursor, can be synthesized size-selectively by inducing transformation in the framework structure of the metal NCs by a ligand-exchange reaction. In this study, we selected the reaction of [Au(25)(SC(2)H(4)Ph)(18)](−) (SC(2)H(4)Ph = 2-phenylethanethiolate) with 4-tert-butylbenzenethiol ((t)BuPhSH) as a model ligand-exchange reaction and attempted to obtain new metal NCs by changing the amount of thiol, the central atom of the precursor NCs, or the reaction time from previous studies. The results demonstrated that [Au(23)(SPh(t)Bu)(17)](0), [Au(26)Pd(SPh(t)Bu)(20)](0) (Pd = palladium) and [Au(24)Pt(SC(2)H(4)Ph)(7)(SPh(t)Bu)(11)](0) (Pt = platinum) were successfully synthesized in a high proportion. To best of our knowledge, no report exists on the selective synthesis of these three metal NCs. The results of this study show that a larger variety of metal NCs could be synthesized size-selectively than at present if the ligand-exchange reaction is conducted while changing the reaction conditions and/or the central atoms of the precursor metal NCs from previous studies.