Synthetic, structural and inelastic neutron scattering studies of the hydridobridged cationic complexes [(PMe3)(2)(Y)Pt(mu-H)Pt(Y)(PMe3)(2)](+) (Y=Ph, C6F5, C6Cl5) and of [(PEt3)(2)(H)Pt(mu-H)Pt(Ph)(PEt3)(2)](+)

The mono-hydrido-bridged diplatinum complexes [(PMe3)(2)(C6X5)Pt(mu-H)Pt(C6X5)(PMe3)(2)](CF3SO3) (X = H, F, Cl) were prepared from the corresponding mononuclear species trans-[PtH(C6X5)(PMe3)(2)] and trans-[Pt(C6X5)(S)(PMe3)(2)](CF3SO3) (S = weakly coordinating solvent). The X-ray crystal structures of [(PMe3)(2)(Ph)Pt(mu-H)Pt(Ph)(PMe3)(2)][BPh4], prepared from the corresponding triflate (space group P (1) over bar, a=13.731(5), b=16.192(2), c=23.425(8) Angstrom, alpha=96.46(2), beta=100.54(3), gamma=95.05(2)degrees, Z=4, R=0.043, R-w=0.056 for 6914 observed reflections) and of [(PMe3)(2)(C6F5)Pt(mu-H)Pt(C6F5)(PMe3)(2)](CF3SO3). CH2Cl2 (space group P2(1)/n, a=11.762(2), b=19.500(3), c=19.112(3), beta=105.64(1), Z=4, R=0.038, R-w=0.049 for 2528 observed reflections) were determined. Both cations contain the two planar [Pt(C6X5)(PMe3)(2)] moieties bridged by a hydride ligand, the Pt-Pt bonds being 3.0641(7) and 3.0969(9) Angstrom for X=H and 3.009(1) Angstrom for X=F. Inelastic incoherent neutron scattering studies were carried out on [(PMe3)(2)(C6F5)Pt(mu-H)Pt(C6F5) (PMe3)(2)](CF3SO3), [(PEt3)(2)(H)Pt(mu-H)Pt(Ph)(PEt3)(2)](CF3SO3) and [(PEt3)(2)(Ph)Pt(mu-H)Pt(Ph)(PEt3)(2)](CF3SO3), and vibrational data for the Pt-H-Pt fragments obtained. The values of the nu(asym)/nu(sym) ratios and a semi-empirical correlation were used to obtain approximate values of the Pt-H-Pt bond angles in compounds of this type.