A New 25-Metal-Atom Supracluster - Synthesis, Characterization, And Crystal-Structure Of The Ternary Cluster Compound [Pt2(Aupph3)10ag13cl7]

A new neutral Pt-Au-Ag cluster compound is reported: [Pt2(AuPPh3)10Ag13Cl7]. This 25-metal-atom supracluster is formed by the reaction of [Pt(H)(PPh3)(AuPPh3)7](NO3)2 with Ag(PPh3)(NO3) in a molar ratio of 1:4 with subsequent addition of NaCl. This compound was characterized by elemental analysis, IR and P-31 NMR spectroscopy, FAB-MS, and cyclic voltammetry. The crystal and molecular structure of [Pt2(AuPPh3)10Ag13Cl7] has been determined by a single-crystal X-ray analysis. The compound crystallizes with about 10 solvent molecules in the monoclinic space group P2(1)/m, with a = 17.154(2) angstrom, b = 25.256(2) angstrom, c = 29.889(2) angstrom, beta = 106.13(2)degrees, V = 12439 angstrom3, and Z = 2. Mo Kalpha radiation was used. The residuals are R = 0.089 and R(w) = 0.084 for 3585 observed reflections and 352 variables. The structure consists of two identical icosahedral Pt-centered subunits sharing a single common vertex, which is a silver atom. The central platinum atoms are bound to five gold atoms and seven silver atoms. A triphenylphosphine is attached to each of the gold atoms. The central silver atom is bound to ten silver atoms and two platinum atoms. The peripheral silver atoms are attached to terminal or mu2-bridging Cl ligands.