Structure and Properties of Au₅Cu₆(Dppf)₂(SAdm)₆)(BPh₄)

Phosphine ligand can also effectively regulate the overall structures. Changing the phosphorus ligand from bis(diphenylphosphino)methane (Dppm) to bis(diphenylphosphino)ferrocene (dppf), a new atomically precise Au–Cu alloy nanocluster Au₅Cu₆(Dppf)₂(SAdm)₆(BPh₄) (Au₅Cu₆ for short) was synthesized, whose structure was determined by single-crystal X-ray diffraction (SCXRD) and further confirmed by electrospray ionization mass spectrometry (ESI-MS) and X-ray photoelectron spectrospray (XPS). Like the structure of Au₂Cu₆, the structure of Au₅Cu₆ was formed via (DppfAu₂)-Au-(DppfAu₂) core interpenetrating a closed hexagon (CuSR)₆ complexes. The time-dependent density functional perturbation theory (TD-DFT) and partial density of states (PDOS) calculations figured out the atomic contributions to the related optical transitions. Meanwhile, metal engineering and stability tests in thermal, oxidizing, and reducing environments as well as in C₆H₁₁SH showed that the Au₅Cu₆(Dppf)₂(SAdm)₆(BPh₄) was particularly stable. This novel Au₅Cu₆(Dppf)₂(SAdm)₆(BPh₄) will enrich the small-size gold–copper alloy clusters and contribute to the application and theoretical analysis of gold–copper alloy clusters.