HYDROLYSIS AND DIMERIZATION OF NITRILE TO DIACETAMIDE AND CRYSTAL-STRUCTURES OF CHLORO(2,2,2,2',2',2'-HEXACHLORODIACETAMIDO)(DIMETHYL SULFOXIDE)PLATINUM(II) AND CIS-AQUADICHLORO(DIMETHYL SULFOXIDE)PLATINUM(II)

The reaction of K[Pt(DMSO)Cl3] with trichloroacetonitrile in aqueous solution adjusted to pH = 7 with NaOH produces, after 24 h, a blue solution from which blue crystals were grown and analyzed by X-ray diffraction. The compound is a monomeric chelate Pt(II) species containing a deprotonated imide ligand, formed from the dimerization of trichloroacetonitrile. The crystals of Pt(DMS0)Cl(C4NO2Cl6) are monoclinic, P21/n space group, with a = 11.214 (9) Å, b = 11.555 (11) Å, c = 13.841 (9) A, β = 107.18 (5)°, V = 1714 (2) Å3, and Z = 4. The structure was refined to R = 0.040 and Rw = 0.039. The bond distances are Pt-Cl = 2.301 (2), Pt-S = 2.217 (2), Pt-O(1) = 2.002 (5), and Pt-O(2) = 1.950 (5) Å. The imide ligand is planar, and its dihedral angle with the Pt(II) coordination plane is 1.7°. After being exposed to air more than 7 months, the crystal became yellow. The blue color was probably caused by a coating on the surface by a blue amorphous Pt complex. When the pH of the aqueous solution is not adjusted (pH = 2), K[Pt(DMSO)Cl3] reacts with trichloroacetonitrile to give a yellow powder and very pale yellow crystals, identified by diffraction methods as cis-Pt(DMS0)(H2O)Cl2. The crystals are orthorhombic, P212121 space group, with a = 8.900 (3) Å, b = 9.020 (3) Å, c = 10.493 (4) Å, and Z = 4, and the structure was refined to R = 0.044 and Rw = 0.052. The Pt-Cl bonds are 2.337 (5) and 2.292 (5) Å, and the Pt-S distance is 2.191 (4) Å, while the Pt-O bond is 2.076 (16) Å. The crystal is stabilized by hydrogen bonds between the aqua ligand and one Cl ligand and O of DMSO. © 1990, American Chemical Society. All rights reserved.