Cyclopentadienyls of palladium and platinum

Abstract

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.