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)10Ag1 3Cl7]. This 25-metal-atom supracluster is formed by the reaction of [P t(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 e lemental analysis, IR and P-31 NMR spectroscopy, FAB-MS, and cyclic vo ltammetry. The crystal and molecular structure of [Pt2(AuPPh3)10Ag13Cl 7] has been determined by a single-crystal X-ray analysis. The compoun d 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, a nd Z = 2. Mo Kalpha radiation was used. The residuals are R = 0.089 an d R(w) = 0.084 for 3585 observed reflections and 352 variables. The st ructure consists of two identical icosahedral Pt-centered subunits sha ring a single common vertex, which is a silver atom. The central plati num atoms are bound to five gold atoms and seven silver atoms. A triph enylphosphine is attached to each of the gold atoms. The central silve r atom is bound to ten silver atoms and two platinum atoms. The periph eral silver atoms are attached to terminal or mu2-bridging Cl ligands.