Metal-metal interactions in platinum(II)/gold(I) or platinum(II)/silver(I) salts containing planar cations and linear anions

The salts Pt{C(NHMe)(2)}(4)]Au(CN)(2)](2), Pt{C(NHMe)(2)}(4)]Ag(2)(CN)(3)]Ag(CN)(2)], Pt(en)(2)]Au(CN)(2)](2), Pt(en)(2)]Ag(CN)(2)](2), and Pt(bipy)(2)]Au(CN)(2)](2) have been prepared by mixing solutions of salts containing the appropriate cation with solutions of KAu(CN)(2)] or KAg(CN)(2)]. Because the platinum atom in the cation is sterically protected, the structures of Pt{C(NHMe)(2)}(4)]Au(CN)(2)](2) and Pt{C(NHMe)(2)}(4)]Ag(2)(CN)(3)]Ag(CN)(2)] reveal no close metal-metal interactions. Colorless crystals of Pt(en)(2)]Au(CN)(2)](2) and Pt(en)(2)]Ag(CN)(2)](2) are isostructural and involve extended chains of alternating cations and anions that run parallel to the crystallographic a axis, along with isolated anions. In the chains, the metal-metal separations are relatively short: Pt...Au, 3.1799(3) Angstroms; Pt...Ag, 3.1949(2) Angstroms. In Pt(bipy)(2)]Au(CN)(2)](2), each cation has axial interactions with the anions through close Pt...Au contacts 3.1735(6) Angstroms]. In addition, the anions are weakly linked through Au...Au contacts of 3.5978(9) Angstroms. Unlike the previously reported Pt/Au complex Pt(NH(3))(4)]Au(CN)(2)](2).1.5H(2)O, which is luminescent, none of the salts reported here luminesce.