No abstract

Several cyanogold complexes react with the binuclear nickel complex [(Ni(dien)(H(2)O))(2)(mu-ox)](PF(6))(2).2H(2)O to give the compounds [(Ni(dien)(H(2)O))(2)(mu-ox)]Br(2) (1), [(Ni(dien)(Au(CN)(2)))(2)(mu-ox)] (2), and [(Ni(dien))(2)(mu-ox)(mu-Au(CN)(4))](PF(6)) (3) (dien, diethilenetriamine; ox, oxalate). In the case of compounds 2 and 3, water displacement by the corresponding cyanogold complex takes place, whereas compound 1 is formed by a substitution of the anion. The crystal structures of compounds 1 and 2 present a 2D arrangement where the layers are connected by van der Waals forces (1) or N-H.Ntbd1;C hydrogen bonds (2), where each binuclear complex is hydrogen bonded to its neighbors, whereas compound 3 presents a novel structure where the tetracyanoaurate acts as a bridging ligand to give a polymeric compound. Magnetic studies of these compounds reveal an antiferromagnetic behavior. Finally, density functional theory (DFT) calculations have been performed on isolated models of compounds 2 and 3 in order to gain some insight about the different behavior of the [Au(CN)(2)](-) and [Au(CN)(4)](-) groups as ligands and proton acceptors in hydrogen bonds.

Three novel polymeric compounds [Ni(dien)Ni(CN)4]n(H2O)n (1), [Ni(dien)Pd(CN)4]n (2), and [Ni(dien)Pt(CN)4]n (3) were synthesised by reaction of [{Ni(dien)(H2O)}2(μ‐ox)](PF6)2 with [M(CN)4]2− (M = Ni, Pd, Pt) in aqueous solution. The structure of these compounds contains two [Ni(dien)]2+ cationic units bridged by two [M(CN)4]2− anions in a cis fashion, generating a square‐shaped [Ni2−M2] metal core. The different linking modes between the cores afford a 2D bilayer with encapsulated water in compound 1 and corrugated layers in compounds 2 and 3. These coordination modes are compared to the different bridging modes of tetracyanometalate‐containing compounds retrieved from the CSD database. The three compounds present a very weak antiferromagnetic coupling between the octahedrally coordinated NiII ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

No abstract