Anion‐Directed Regulation of Structures and Luminescence of Heterometallic Clusters.

Anions have been used to regulate the structures and luminescence of heterometallic clusters. Introducing ClO4− into orange‐emissive, butterfly‐like [(C)(Au‐PPhpy2)6Ag4](BF4)6 (1, PPhpy2=bis(2‐pyridyl)phenylphosphine) leads to the formation of red‐emissive [(C)(Au‐PPhpy2)6Ag5(ClO4)3](ClO4)4 (2) with a novel trigonal bipyramidal structure; employing PhCO2− gives yellow‐emissive, hexagram‐like [(C)(Au‐PPhpy2)6Ag6(PhCO2)3](BF4)5 (3). Notably, 1 exhibits weak luminescence in CH2Cl2/CH3OH=1 : 1 (v : v) with a quantum yield (QY) of 0.05, whereas it was dramatically increased to 0.49 and 0.83 for 2 and 3, respectively. Theoretical calculation confirms that the involvement of anions in the electronic structures is responsible for the shifts of emission. The high QYs of 2 and 3 are attributed to the protection provided by ligands and anions. This work demonstrates that anions may serve as an extra designable factor beyond just counterions for functional metal clusters. [ABSTRACT FROM AUTHOR]