Synthesis and Luminescence Properties of Two-Electron Bimetallic Cu–Ag and Cu–Au Nanoclusters via Copper Hydride Precursors

The synthesis, structural characteristics, and photophysical properties of luminescent Cu-rich bimetallic superatomic clusters [Au@Cu 12 (S 2 CN n Pr 2 ) 6 (C≡CPh) 4 ] + ( 1a + ), [Au@Cu 12 {S 2 P(OR) 2 } 6 (C≡CPh) 4 ] + ( 2 + ), ( 2a + = i Pr; 2b + = n Pr), [Au@Cu 12 {S 2 P(C 2 H 4 Ph) 2 } 6 (C≡CPh) 4 ] + ( 2c + ), and [Ag@Cu 12 {S 2 P(O n Pr) 2 } 6 (C≡CPh) 4 ] + ( 3 + ) were studied. Compositionally uniform clusters 1 + - 3 + were isolated from the reaction of dithiolato-stabilized, polyhydrido copper clusters with phenylacetylene in the presence of heterometal salts. By using X-ray diffraction, the structures of 1a + , 2a + , 2b + , and 3 + were able to be determined. ESI-mass spectrometry and elemental analysis confirmed their compositions and purity. The structural characteristics of these clusters are similar with respect to displaying gold (or silver)-centered Cu 12 cuboctahedra surrounded by six dithiocarbamate/dithiophosph(in)ate and four alkynyl ligands. The doping of Au and Ag atoms into the polyhydrido copper nanoclusters significantly enhances their PL quantum yields from Ag@Cu 12 (0.58%) to Au@Cu 12 (55%) at ambient temperature in solution. In addition, the electrochemical properties of the new alloys were investigated by cyclic voltammetry.