Deprotonation reactions by transition-metal peroxo-complexes. Synthesis of aroylhydrazido- and aroylhydroxylamido-complexes of palladium and platinum and the crystal and molecular structures of [Pt(PPh3)2{NHNC(O)C6H4NO2-p}] and [Pt(PPh3)2{ONC(O)C6H5}]

Abstract

By treating [M(PPh₃)₂(O₂)](M = Pd or Pt) with C₆H₅C(O)NHOH, C₆H₅C(NH)NHOH, and p-RC₆H₄C(O)NHNH₂ in ethanol, the complexes [M(PPh₃)₂{ONC(O)C₆H₅}], [Pt(PPh₃)₂{ONC(NH)C₆H₅}], and [Pt(PPh₃)₂{NHNC(O)C₆H₄R-p}](R = H, CH₃, or NO₂) respectively have been obtained. The reactions of [Pt(PPh₃)₂(O₂)] with RNHNH₂(R = H or C₆H₅) lead only to the zerovalent complex, [Pt(PPh₃)₃], while by treating [Pt(PPh₃)₂(O₂)] with C₆H₅NHOH the known complex [Pt(PPh₃)₂(C₆H₅NO)] is obtained. Reactions of the aroylhydrazidoplatinum complexes with molecular oxygen and mineral acids are also reported. The structure of the two title complexes has been determined by X-ray diffraction. The compound [Pt(PPh₃)₂{ONC(O)C₆H₅}] is orthorhombic and crystallizes in space group Pna2₁ with a= 17.365(6), b= 11.218(7), and c= 18.431(8)Å, whereas the disordered [Pt(PPh₃)₂{NHNC(O)C₆H₄NO₂-p}] is monoclinic and crystallizes in space group P2₁/m with a= 15.829(6), b= 12.269(5), c= 11.833(5)Å, and β= 93.51(3)°. Both structures have been solved by Patterson and Fourier methods, and refined to R 0.031 and 0.062 for 2 057 and 2 119 independent reflections, respectively. Both compounds, in the solid state, are essentially square-planar complexes of Pt^II. The differences between the two structures, which display different packing efficiency, are mainly due to the conformations of the phosphine groups, which are imposed by the chelating ligands.