Palladium(II) and platinum(II) derivatives with N,O ligands

The preparation of a series of Pd(II) and Pt(II) derivatives with three N,O hybrid ligands 1-(2-pyridyl)ethyldiphenylphosphine oxide, L-1; (2-pyridyl)methyldiphenylphosphine oxide, L-2 and 2-pyridyldiphenylphosphine oxide, L-3 is described. Depending on the ligand to metal molar ratio, either 1:1 [LMCl2]{[(LPdCl2)-Pd-1] 1, [(LPdCl2)-Pd-2] 2, [(LPdCl2)-Pd-3] 3, [(LPtCl2)-Pt-1] 4} or 2:1 [L2MCl2] {[(L2PdCl2)-Pd-1] 5, [(L2PdCl2)-Pd-2], 6, [(L2PtCl2)-Pt-1] 7} adducts are obtained. In addition, an ionic species [(L2Pd)-Pd-1][PF6](2) 8, has been isolated by treatment of complex 5 with AgPF6. The structures in the solid state of compounds 5b . MeOH . H2O, 6 . MeOH and 4 . CH2Cl2 have been solved by X-ray diffraction. The structures of trans-[(L2PdCl2)-Pd-1] 5b (one of the diastereomers of 5) and trans-[(L2PdCl2)-Pd-2] 6 are rather different, the former being a chiral molecule (R,R enantiomer) with a C-2 axis perpendicular to the plane of the metal, the latter, 6, being a centrosymmetric molecule. In both the species the ligand is bonded through the nitrogen atom. In complex [(LPtCl2)-Pt-1] 4, the ligand is coordinated through the N and O atoms to form a six-membered ring which adopts a boat-like conformation. The structure reveals a fairly short interaction between one hydrogen atom of the Me group in an axial position and the platinum atom, Pt ... H 2.69 Angstrom. Short contacts Pd ... H are also observed in the structures of compounds 5b and 6. Some aspects of the reactivity of the new species are discussed.

The preparation of a series of Pd(II) and Pt(II) derivatives with three N,O hybrid ligands 1-(2-pyridyl)ethyldiphenylphosphine oxide, L1; (2-pyridyl)methyldiphenylphosphine oxide, L2 and 2-pyridyldiphenylphosphine oxide, L3 is described. Depending on the ligand to metal molar ratio, either 1 : 1 [LMCl2] {[L1PdCl2] 1, [L2PdCl2] 2, [L3PdCl2] 3, [L1PtCl2] 4} or 2 : 1 [L2MCl2] {[L1 2PdCl2] 5, [L2 2PdCl2] 6, [L1 2PtCl2] 7} adducts are obtained. In addition, an ionic species [L1 2Pd][PF6]2 8, has been isolated by treatment of complex 5 with AgPF6. The structures in the solid state of compounds 5b?MeOH?H2O, 6?MeOH and 4?CH2Cl2 have been solved by X-ray diffraction. The structures of trans-[L1 2PdCl2] 5b (one of the diastereomers of 5) and trans-[L2 2PdCl2] 6 are rather different, the former being a chiral molecule (R,R enantiomer) with a C2 axis perpendicular to the plane of the metal, the latter, 6, being a centrosymmetric molecule. In both the species the ligand is bonded through the nitrogen atom. In complex [L1PtCl2] 4, the ligand is coordinated through the N and O atoms to form a six-membered ring which adopts a boat-like conformation. The structure reveals a fairly short interaction between one hydrogen atom of the Me group in an axial position and the platinum atom, Pt ? ? ? H 2.69 Å. Short contacts Pd ? ? ? H are also observed in the structures of compounds 5b and 6. Some aspects of the reactivity of the new species are discussed.