THE SYNTHESES AND VIBRATIONAL-SPECTRA OF THE HOMOLEPTIC METAL ACETONITRILE CATIONS [AU(NCCH3)(2)](- THE CRYSTAL AND MOLECULAR-STRUCTURES OF[M(NCCH3)(4)][SBF6](2).CH3CN, M = PD OR PT(), [PD(NCCH3)(4)](2+), [PT(NCCH3)(4)](2+), AND THE ADDUCT CH3CN.SBF5 )

Solvolyses of the homoleptic metal carbonyl salts [M(CO)(4)][Sb2F11](2 ), M = Pd or Pt, in acetonitrile leads at 50 degrees C both to complet e ligand exchange for the cations as well as to a conversion of the di -octahedral anion [Sb2F11](-) into [SbF6](-) and the molecular adduct CH3CN . SbF5 according to: [M(CO)(4)][Sb2F11](2) + 7 CH3CN --> [M(NCCH 3)(4)][SbF6](2) . CH3CN + 2 CH3CN SbF5 + 4 CO M = Pd, Pt The monosolva ted [M(NCCH3)(4)][SbF6](2) . CH3CN are obtained as single crystals fro m solution and are structurally characterized by single crystal x-ray diffraction. Both salts are isostructural. The cations are square plan ar but the N-C-C-sceletial groups of the ligands depart slightly from linearity. The new acetonitrile complexes as well as [Au(NCCH3)(2)][Sb F6] and the adduct CH3CN . SbF5 are completely characterized by vibrat ional spectroscopy.