Reaction chemistry of some new hybrid phosphine amide complexes of platinum(II) and palladium(II). Isolation and X-ray structure determination of an ortho-metalated platinum(II) complex derived from a chelated phosphine amide complex of platinum(II)

Article abstract of DOI:10.1021/om00133a024

Refluxing the complex trans-PtCl₂(o-Ph₂PC₆H₄NHC(O)Ph) ₂ in DMF/Et₃N gives the cyclometalated complex cis-Pt(o-Ph₂PC₆H₄NC(O)C₆H ₄)(o-Ph₂PC₆H₄NHC(O)Ph). The complex crystallizes in a triclinic P1 space group with a = 12.038 (3) ?, b = 12.576 (5) ?, c = 16.220 (6) ?, α = 105.80 (3)°, β = 104.84 (3)°, and γ = 95.73 (3)°. The structure shows respective values of 2.063 (7) and 2.065 (8) ? for Pt-N(1) and Pt-C(3). The monodentate P-bonded PNH(CPhO) ligand shows a close "agostic" interaction of the type N-H?Pt. The hydrogen atom has been located at a distance of 2.318 (22) ? from Pt. The analogous palladium complex has been synthesized. The transfer of the ortho carbon hydrogen to the amido nitrogen has been confirmed by deuteration studies using o-Ph₂PC₆H₄NHC(O)C₆D₅. The "agostic" hydrogen atom undergoes H/D exchange with benzene, acetonitrile, or chloroform. These cyclometalated complexes add HCl to give cis-MCl₂(o-Ph₂PC₆H₄NHC(O)Ph) ₂ (M = Pd, Pt). With CF₃CO₂H the reaction is reversible, and N-alkylation occurs with Me₂SO₄ to give [Pd(o-Ph₂PC₆H₄N(Me)C(O)C₆H ₄)(o-Ph₂PC₆H₄NHC(O)Ph)]SO ₄Me. These amido complexes are stable to water and acetic acid.