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 cm(3) K mol(-1) and a Weiss temperature, theta, 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.