Synthesis, Structural Characterization, and Electronic Structure Analysis of F₂-type Superatomic Molecules

The investigation of bonding interactions between superatoms continues to be a largely unexplored area of study. In this study, we present the synthesis and characterization of two F₂-type superatomic molecules [Au₂Ag₂₅(C₇H₄NOS)₁₃(DPPB)₃] and [Au₉Ag₁₈(C₅H₄NS)₁₁(DPPM)₅]²⁺ (Au and Au for short, respectively). The overall structures were confirmed via X-ray crystallography, revealing the horizontal expansion of the biicosahedral Au₂Ag₂₁ yielding [Au₂Ag₂₅(C₇H₄NOS)₁₃(DPPB)₃] and vertical expansion of the biicosahedral Au₈Ag₁₅ yielding [Au₉Ag₁₈(C₅H₄NS)₁₁(DPPM)₅]²⁺. Furthermore, their electronic structures were elucidated through density functional theory (DFT) calculations. Spectroscopic analysis of electronic absorption characteristics, in conjunction with Tamm-Dancoff approximation DFT (TDA-DFT) calculations, revealed that the Au₂Ag₂₁⁽⁺⁹⁾ and Au₈Ag₁₅⁽⁺⁹⁾ cores were analogues of the F₂ molecule in electronic configuration.