MOLECULAR AND CRYSTAL-STRUCTURES OF CIS-PT(DMSO)(C2H5CN)CL2 AND CL(DMSO)PT(MU-N(CH3)CHO)2PT(DMSO)CL

The aqueous reaction of K[Pt(DMSO)Cl3] with propionitrile at normal pH (approximately 2.4), gave the product Pt(DMSO)(C2H5CN)Cl2 which was studied by X-ray diffraction methods. The crystals belongs to the monoclinic P2(1) space group, with a = 8.188(3), b = 7.193(3), c = 10.325(4) angstrom, beta = 116.76(3)-degrees and Z = 2. The results have confirmed the cis geometry of the complex. The coordination around the Pt atom is square planar, but there are important distortions towards a square pyramidal structure. The bond distances are: Pt-Cl, 2.337(5), 2.328(3); Pt-S, 2.217(4); Pt-N, 1.951(6) angstrom. The aqueous reaction of K[Pt(DMSO)Cl3] with N-methylformamide at neutral pH (adjusted with NaOH) produced the N-methylformamido-bridged dimer Cl(DMSO)Pt(mu-N(CH3)CHO)2Pt(DMSO)Cl whose crystal structure was determined. The compound belongs to the monoclinic P2(1)/c space group, with a = 8.482(3), b = 10.512(5), c = 24.124(10) angstrom, beta = 124.52(2)-degrees and Z = 4. The results have shown that the dimer is the head-to-tail isomer with the DMSO ligands located in trans position to the 0-formamido atoms. The bond distances are: Pt-Cl, 2.314(3), 2.305(4); Pt-S, 2.183(3), 2.198(3); Pt-0, 2.049(7), 2.040(9); Pt-N, 2.018(9), 2.019(9) angstrom. The dihedral angle between the two Pt(II) planes is 42-degrees.