Identification of an Eight-Electron Superatomic Cluster and Its Alloy in One Co-crystal Structure.

Herein we report a crystal structure of [Au_0.5Ag_0.5@Ag₂₀{S₂P(OⁱPr)₂}₁₂](PF₆) [Cl@Ag₈{S₂P(OⁱPr)₂}₆](PF₆) (1), which compositions were supported by positive-mode electrospray ionization mass spectrometry. The structural elucidation indicates that the encapsulated atom of an Ag₁₃ the entered icosahedron can be replaced by a gold atom. Surprisingly, the capping Ag atoms on the surface of an icosahedron in 1 reveal a different arrangement from the previously reported [Ag₂₁{S₂P(OⁱPr)₂}₁₂](PF₆) of C₃ symmetry. Besides, the preference for the central silver atom being oxidized by Au(I) is rationalized by the DFT calculations on three different computed [AuAg₂₀{S₂PH₂}₁₂]⁺ models having C₁, C₃, and T symmetry, respectively. [ABSTRACT FROM AUTHOR]