Crystal structure of μ-cyanido-1:2κ(2) N:C-dicyanido-1κC,2κC-bis­(quinolin-8-amine-1κ(2) N,N′)-2-silver(I)-1-silver(II): rare occurrence of a mixed-valence Ag(I,II) compound

The title dinuclear complex, [Ag(2)(CN)(3)(C(9)H(8)N(2))(2)], may be considered as an Ag(II) compound with the corresponding metal site coordinated by two bidentate quinolin-8-amine mol­ecules, one cyanide group and one dicyanidoargentate(I) anion, [Ag(CN)(2)](−). Since this latter ligand contains an Ag(I) atom, the complex should be a class 1 or class 2 mixed-valence compound, according to the Robin–Day classification. The Ag(II) atom is six-coordinated in a highly distorted octa­hedral geometry, while the Ag(I) atom displays the expected linear geometry. In the crystal, the amino groups of the quinolin-8-amine ligands form N—H⋯N hydrogen bonds with the N atoms of the non-bridging cyanide ligands, forming a two-dimensional network parallel to (102). The terminal cyanide ligands are not engaged in polymeric bonds and the title compound is an authentic mol­ecular complex. The title mol­ecule is thus a rare example of a stable Ag(I,II) complex, and the first mixed-valence Ag(I,II) mol­ecular complex characterized by X-ray diffraction.