Nickel(II) and Copper(II) Dicyanoargentate Complexes with Ethylenediamine and 4,4´-Bipyridyl Ligands

The reactions of an aqueous solution of potassium dicyanoargentate with a mixture of nickel(II) or copper(II) chloride and ethylenediamine or 4,4´-bipyridyl in ethanol afford coordination polymers [Ni(En)2(Ag(CN)2)][Ag(CN)2] (I), [Cu(En)2(Ag(CN)2)][Ag(CN)2] (II), and [Cu(4,4´-Bipy)2(Ag(CN)2)2] (III) characterized by XRD (CIF files CCDC nos. 2225984 (I), 2214320 (II), and 2229270 (III)) and IR spectroscopy. According to the XRD data, the crystals of complexes I and II are formed by 1D chains {··NC– Ag–CN–M(En)2··}n (M = Ni (I), Cu (II)) linked with each other by the dicyanoargentate anions via argentophilic contacts (Ag···Ag 3.288(8) Å (I), 3.1616(14) Å (II)). The crystal of compound III consists of independent interpenetrating 3D networks built of polymer layers {Cu[Ag(CN)2]2}n bound to each other by the 4,4´-bipyridyl molecules. The bipyridyl linkers connect the Cu centers with the Ag centers of the [Ag(CN)2]– anions thus providing the tridentate coordination of the silver atoms. No Ag···Ag interactions are observed in the crystal of complex III.