Synthesis and characterization of mono-and bi-nuclear palladium(II) and platinum(II) complexes containing acetamidine ligands

Abstract

The reactions of [M2Cl2(μ-Cl)2(PR3)2] with acetamidines in 1:2 stoichiometry afforded mononuclear complexes, [MCl2{ArNHC(Me)NAr}(PR3)] (I) (M = Pd or Pt; R3 = Et3, Bu3, Me2Ph, MePh2; Ar = Ph or 4-MeC6H4 (tol)). Treatment of [M2Cl4(PR3)2] with Li[ArNC(Me)NAr] under anerobic conditions gave acetamidino-bridged binuclear complexes, [M2Cl2(μ-ArNC(Me)NAr)2(PR3)2] (II). The reaction of [Pd2(μ-Cl)2(η3-allyl)2] with Ag[ArNC(Me)NAr] gave acetamidino-bridged allyl complexes [Pd2(μ-ArNC(Me)NAr)2(η3-allyl)2] (III). All the complexes were characterized by elemental analyses and NMR (1H, 31P, 195Pt) spectroscopy. The mononuclear complexes (I) exist in two isomeric forms differing in the coordination of monodentate acetamidine ligand. The 31P and 195Pt NMR data on binuclear complexes (II) indicate that there is no significant Pt–Pt interaction. The allyl complexes (III) (allyl = C3H5) exhibit formation of all three possible isomers, whereas methallyl (allyl = C4H7) derivatives exist only in one configuration. Key words: palladium, platinum, acetamidine, NMR (1H, 31P, 195Pt), mononuclear complexes, binuclear complexes.