Synthesis, crystal structure and electrospray ionisation mass spectrometry of a novel one-dimensional cyano-bridged Ni(II)-Au(I) polymer

Reaction of nickel(II) acetate with tren [tren = tris(2-aminoethyl)amine] and K[Au(CN)2] produced [Ni(tren)Au(CN)2][Au(CN)2] (1), which consists of cis-[Ni(tren)]2+units linked by Au(CN)2-to form infinite zig-zag chains. The complex obeys the Curie-Weiss law throughout the temperature range 4-300 K, with a Curie constant of 1.10 cm3K mol-1and a Weiss temperature, θ, of 0.62 K. The electrospray mass spectrum of 1 in H2O-CH3OH shows peaks that can be described by the general formulae {[Ni(tren)](n)[Au(CN)2](2n-1)}+(n = 1-4) and {[Ni(tren)](n)[Au(CN)2](2n-2)}2+(n = 2-9). Based on the crystal structure of the polymer, these ions are best described as composed of an oligomeric cation that may be associated with one or more Au(CN)2/-counter ions.