Synthesis and structure of Pt(II) acetamidate complexes containing N,N-dimethyl-substituted ethylenediamine and trimethylenediamine

Reactions of acetamide with platinum(II) diamines [Pt(N,N-DimeEn)Cl2], [Pt(Tm)Cl2], and [Pt(N,N-DimeTm)Cl2] (N,N-DimeEn = (CH3)2N(CH2)2NH2, Tm = NH2(CH2)3NH2, N,N-DimeTm = (CH3)2N(CH2)3NH2) with preliminary precipitation of chlorine ions by silver salts gave binuclear Pt(II) acetamidates [Pt2(CH3)2N(CH2)2NH2)2(μ-NHCOCH3)2](NO3)2 · H2O (I), [Pt2(NH2(CH2)3NH2)2)(μ-NHCOCH3)2](NO3)2 · H2O (II), and [Pt2(CH3)2N(CH2)3NH2)2(μ-NHCOCH3)2](HSO4)2 (III), whose crystal structures were determined. Crystals of I are monoclinic: a = 14.459(2) A, b = 17.197(3) A, c = 9.822(2) A, β = 105.923(10)°, V = 3348.6(8) A3, space group P2(1)/c, Z = 4, R hkl = 0.0419 for 6663 reflections. Complex I is a binuclear acetamidate with bridging (NHCOCH3)− ligands, one of which is bound to two Pt atoms through the N and O atoms, and the other ligand is bound only through the N atom. The Pt-Pt distance is 2.987(1) A. Crystals of II are monoclinic: a = 10.213(7) A, b = 13.373(9) A, c = 16.533(11) A, β = 97.971(9)°, V = 2236(3) A3, space group P2(1)/n, Z = 4, R hkl = 0.557 for 6462 reflections. The Pt-Pt distance is 3.057(1) A. Crystals of III are monoclinic: a = 10.557(12) A, b = 18.531(2) A, c = 14.4744(17) A, β = 108.705(2)°, V = 2682(5) A3, space group P2(1)/n, Z = 4, R hkl = 0.569 for 8506 reflections. The Pt-Pt distance is 3.202(1) A. Complexes II and III are binuclear acetamidates, in which two chelating Pt(Tm) or Pt(N,N-DimeTm) moieties are coordinated through the N and O atoms of (NHCOCH3)− cis-bridges.