Crystal Structures of Two New Gold-Copper Bimetallic Nanoclusters: CuxAu25_xPPh3)10(PhC2H4S)5Cl22+ and Cu3Au34(PPh3)13(tBuPhCH2S)6S23+

Herein, we report the synthesis and atomic structures of the cluster-assembled CuxAu25-x(PPh3)(10-)(PhCH2CH2S)(5)Cl-2(2+) and Cu3Au34(PPh3)(13)((BuPhCH2S)-Bu-t)(6-)S-2(3+) nanoclusters (NCs). The atomic structures of both NCs were precisely determined by single-crystal X-ray crystallography. The CuxAu25-x(PPh3)(10)(PhC2H4S)(5)Cl-2(2+) NC was assembled by two icosahedral M-13 via a vertex sharing mode. The Cu atom partially occupies the top and waist sites and is monocoordinated with chlorine or thiol ligands. Meanwhile, the Cu3Au34(PPh3)13((BUPhCH2S)-B-t)6-S-2(3+) NC can be described as three 13-atom icosahedra sharing three vertexes in a cyclic fashion. The three Cu atoms all occupy the internal positions of the cluster core. What is more important is that all three Cu atoms in Cu3Au34 are monocoordinated by the bare S atoms. The absorption spectra of the as-synthesized bimetallic NCs reveal that the additional metal doping and different cluster assemblies affect the electronic structure of the monometallic NCs.