Cyclopentadienyls of palladium and platinum

The binuclear halogen-bridged complexes (R3P)2Pd2X4(R = Et, Pri, or Ph; X = Cl, Br, or I) react with TlC5H5 to produce (R3P)(π-C5H5)PdX. Yields are poor when analogous platinum complexes are used, but halogen-bridged organoplatinum compounds (R13P)R2Pt(µ-X)2PtR2(PR13) give good yields of (R13P)(π-C5H5)PtR2[R1= Et; R2= Ph or o-tolyl; R1= Bun; R2= C(O)Ph].The complexes (R3P)(π-C5H5)MX (M = Pd or Pt) react with tertiary phosphines to give either ionic π-bonded derivatives [(R3P)2(π-C5H5)M]+X– or unstable σ-bonded compounds (R3P)2M(σ-C5H5)X, depending on the nature of the solvent and the tertiary phosphine. The same complexes can be produced from (R3P)2MX2 and TlC5H5. The diarsine complex [C6H4(AsEt2)2]Pt(σ-C5H5)Cl, produced from [C6H4(AsEt2)2]PtCl2 and TlC5H5, is stable in air to 130 °C. σ-Bonded cyclopentadienyl complexes are also prepared from the reaction of (R13P)(π-C5H5)PtR2 with R13P or CO. The 1H n.m.r., i.r., and mass spectra of the compounds are discussed.