cis- and trans-Dichloro(3,6-dihydro-1,2-oxazine-N)(dimethyl sulfoxide-S)-platinum(II)

Both the cis, (I), and tuans, (II), isomers of the title complex, [PtCl2(C4 H7NO)(C2H6OS)], possess relatively undistorted square-planar geometries abo ut the Pt atoms. For (I), cis L-Pt-L angles are in the range 88.8 (2)-91.08 (8)degrees, while trans angles are 178.61 (8) and 179.4 (2)degrees. For (I I), cis L-Pt-L 86.1(3)-93.7(1)degrees, and trans L-Pt-L 175.5(1) and 179.1( 3)degrees. The dimethyl sulfoxide (dmso) ligand adopts a normal pyramidal g eometry in both complexes. In (I), the S=O bond essentially eclipses the ad jacent Pt-N bond, while the oxazine ligand in (I) is twisted so as to avoid steric interactions with the adjacent chloride ligand. By contrast, the dm so ligand in (II) is rotated such that the S=O bond is approximately perpen dicular to the square plane, while the oxazine ligand is once again twisted out of the plane by a similar amount as in (I). These are the first struct ural examples of square-planar platinum(II) complexes containing a 1,2-oxaz ine ligand.