Full Protection of Intensely Luminescent Gold(I)–Silver(I) Cluster by Phosphine Ligands and Inorganic Anions

Abstract An intensely luminescent gold(I)–silver(I) cluster [(C)(AuPPhpy 2 ) 6 Ag 6 (CF 3 CO 2 ) 3 ](BF 4 ) 5 (PPhpy 2 =bis(2‐pyridyl)phenylphosphine) ( 3 ) is synthesized by the reaction of [(C)(AuPPhpy 2 ) 6 Ag 4 ](BF 4 ) 6 with AgCF 3 CO 2 . All eight faces of the octahedral C@Au 6 core in 3 are capped, that is, six faces are capped by silver ions and two by tetrafluoroborates. Cluster 3 is intensely luminescent in solution with a quantum yield of 92 %. Ligation of CF 3 CO 2 − ions is vital for the construction and emission properties of 3 , as confirmed by DFT calculations. BF 4 − ions are involved in the protecting sphere of the metal core, as evidenced by 19 F NMR data. The participation of phosphines, CF 3 CO 2 − , and BF 4 − ions in the protection of the emissive core and the enhancement of the rigidity of the cluster result in the high emission efficiency. This is the first example of organic ligands and inorganic anions forming a rigid protecting sphere for luminescent coinage‐metal clusters.