SYNTHESIS OF THE CIS-ISOMERS AND TRANSISOMERS OF TERT-BUTYLAMINEDICHLORO-(DIMETHYL SULPHOXIDE)PLATINUM(II) AND X-RAY STRUCTURE-ANALYSIS OF THE CIS COMPOUND

Treatment of cis-dichlorobis(dimethyl sulphoxide)platinum(II) [(1)] wi th an excess of tert-butylamine in MeOH yields tert-butylamine-trans-d ichloro(dimethyl sulphoxide)-platinum(II) [(tr-5)], rather than the ci s-diaminechloro(dimethyl sulphoxide)platinum(II) cation expected by an alogy with similar reactions reported in the literature. The correspon ding cis isomer [(cis-5)] is prepared from the same reactants (and sim ilarly from K2PtCl4 and tert-butylamine) in DMSO medium, in which the initially formed trans compound partially isomerizes to the thermodyna mically favoured cis complex. The molecular structure of (cis-5) is de termined by X-ray analysis. The coordination around the Pt atom is squ are-planar, and the DMSO ligand is S-coordinated. The lengths of the P t-Cl bonds cis and trans to the DMSO ligand are 2.296(11) and 2.321(10 ) angstrom, respectively, and are well within expected ranges. Interat omic distances within the amine and DMSO ligands are normal.