SYNTHESIS AND CRYSTAL-STRUCTURE OF A PLATINUM SILVER CLUSTER COMPOUND, [PT3AG(O3SCF3)(MU-CO)3(PCY3)2(DPPP)] (CY = C6H11, DPPP = ((C6H5)2P)2C3H6) WITH A DISTORTED TETRAHEDRAL GEOMETRY

The cluster compound [Pt3Ag(O3SCF3)(mu-CO)3(PCy3)2(dppp)] (2) (Cy = C6H11, dppp = {(C6H5)2P}2C3H6) has been obtained in high yield from the reaction between [Pt3(mu-CO)3(PCy3)2(dppp)] (1) and AgCF3SO3. The molecular structure of [Pt3Ag(O3SCF3)(mu-CO)3(PCy3)2-(dppp)].2C6H5CH3 has been determined by X-ray diffractometry. The structure is based on a distorted tetrahedron. One Pt-Pt bond is significantly shorter, at 2.653(2) angstrom, than the other two, which have lengths of 2.709(2) and 2.697(2) angstrom, respectively. Similarly one Pt-Ag bond is, at 2.690(3) angstrom, considerably shorter than the other two, which are 2.927(3) and 2.919(4) angstrom. The CF3SO3- anion is coordinated weakly to the silver through one oxygen atom (Ag-O = 2.30(3) angstrom. P-31{H-1} NMR studies have demonstrated that the tetrahedral structure is maintained in solution.