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 d10 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]n (M = Cu, n = 3; M = Ag or Au, n = 4), which are characterized by a central core constituted of interacting d10 metal ions, surrounded by the molybdenum atoms. When M = Cu, the six metal atoms form a ν2-triangular core whereas when M = Ag or Au, a ν2-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 M[m]2 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 ν2-square, octanuclear, trimetallic complexes [CuAg3{MoCp(CO)3}4] (7) and [CuAu3{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)}{Cu2[MoCp(CO)3]3}]2 (9).