SYNTHESIS AND CRYSTAL-STRUCTURE OF (C5H5)MO(CO)(3)(AUPPH3) AND [(C5H5)MO(CO)(2)(AUPPH3)(4)]PF6

CpMo(CO)(3)(AuPPh3) is obtained by the reaction of Li[CpMo(CO)(3)] wit h Ph3PAuCl at -95 degrees C in CH2Cl2. It crystallizes in the monoclin ic space group C2/c with a = 2625.1(7), b = 883.2(1), c = 2328.4(7) pm , beta = 116.39(1)degrees und Z = 8. In the complex the AuPPh3 group i s coordinated to the CpMo(CO)(3) fragment with a Au-Mo bond of 271,0 p m. The Mo atom thus achieves a square pyramidal coordination with the center of the Cp ring in apical position. CpMo(CO)(3)(AuPPh3) reacts u nder uv irradiation with an excess of Ph3PAuN3 to afford the cluster c ation [CpMo(CO)(2)(AuPPh3)(4)](+). It crystallizes as [CpMo(CO)(2)(AuP Ph3)(4)]PF6 . 2 CH2Cl2 in the orthorhombic space group P2(1)2(1)2(1) W ith a = 1553.9(1), b = 1793.8(2), c = 2809.8(7) pm und Z = 4. The five metal atoms form a trigonal bipyramidal cluster skeleton with the Mo atom in equatorial position. The Mo-Au distances range from 275.5 to 2 80.8 pm, and the Au-Au distances are between 281.2 and 285.6 pm.