Observable but Not Isolable: The RhAu (PET) Nanocluster.

The synthesis and characterization of RhAu (PET) (PET = 2-phenylethanethiol) is described. The cluster is cosynthesized with Au (PET) and rhodium thiolates in a coreduction of RhCl , HAuCl , and PET. Rapid decomposition of RhAu (PET) occurs when purified from the other reaction products, precluding the study of isolated cluster. Mixtures containing RhAu (PET) , Au (PET) , and rhodium thiolates are therefore characterized. Mass spectrometry, X-ray photoelectron spectroscopy, and chromatography methods suggest a combination of charge-charge and metallophilic interactions among Au (PET) , rhodium thiolates and RhAu (PET) resulting in stabilization of RhAu (PET) . The charge of RhAu (PET) is assigned as 1+ on the basis of its stoichiometric 1:1 presence with anionic Au (PET) , and its stability is contextualized within the superatom electron counting rules. This analysis concludes that the Rh atom absorbs one superatomic electron to close its d-shell, giving RhAu (PET) a superatomic electron configuration of 1S 1P . Overall, an updated framework for rationalizing open d-shell heterometal dopant electronics in thiolated gold nanoclusters emerges.