Heterometallic chains and clusters with gold-transition metal bonds: synthesis and interconversion.

Anionic, metal-metal bonded heterotrinuclear chain complexes of the type M{MoCp(CO)(3)}(2) with M = Cu(I), Ag(I), and Au(I) have been prepared by reaction between a d(10) metal precursor complex and the carbonylmetalate MoCp(CO)(3). These complexes have been structurally characterized by X-ray diffraction and used as precursors to neutral 2-D hexa- or octanuclear mixed-metal clusters of the general formula MMoCp(CO)(3) (M = Cu, n = 3; M = Ag or Au, n = 4), which are characterized by a central core constituted of interacting d(10) metal ions, surrounded by the molybdenum atoms. When M = Cu, the six metal atoms form a nu(2)-triangular core whereas when M = Ag or Au, a nu(2)-square structure is observed for the octanuclear metal core. It is shown in the case of M = Cu and Ag that interconversion between the metal chain complexes of stoichiometry Mm and the clusters {M[m]}(n) is possible, and the position of the equilibrium depends solely on the respective stoichiometry of the reagents. The new nu(2)-square, octanuclear, trimetallic complexes [CuAg(3){MoCp(CO)(3)}(4)] (7) and [CuAu(3){MoCp(CO)(3)}(4)] (8) have also been obtained and characterized in the solid-state by X-ray diffraction, as well as the unexpected double pentanuclear complex {Na(dme)}{Cu(2)MoCp(CO)(3)} (9).