PACKING EFFECTS ON MOLECULAR GEOMETRIES OF PLATINUM COMPLEXES - SYNTHESIS AND CRYSTAL-STRUCTURES OF DI-MU-HYDROXO-BIS[BIS(DIMETHYL SULFOXIDE)PLATINUM(II)] TETRAFLUOROBORATE AND DI-MU-HYDROXO-BIS [BIS(DIMETHYL SULFOXIDE)PLATINUM(II)] TRIFLUOROMETHANESULFONATE DIHYDRATE

The crystal structures of di-mu-hydroxo-bis[bis(dimethyl sulfoxide)platinum(II)] tetrafluoroborate and di-mu-hydroxo-bis[bis(dimethyl sulfoxide)platinum(II)] trifluoromethanesulfonate dihydrate have been determined from X-ray intensity data, collected at room temperature with a CAD 4 diffractometer. Crystal data at room temperature (MoK-alpha lambdaBAR = 0.7107 angstrom) are: [Pt2(OH)2(DMSO)4](BF4)2, (DMSO = (CH3)2SO), triclinic, P1BAR, Z = 1, a = 7.193(1), b = 8.681(3), c = 10.937(2) angstrom, alpha = 106.02(2), beta = 104.08(1), gamma = 103.30(2)-degrees and V = 603.5(2) angstrom3. The refinement converged to R = 0.064 for 1972 reflexions with I > 3-sigma(I). [Pt2(OH)2(DMSO)4]-(CF3SO3)2.2H2O, orthorhombic, Pbca, Z = 4, a = 11.188(1), b = 17.106(4), c = 16.226(3) angstrom and V = 3105.4(6) angstrom3. The refinement converged to R = 0.045 for 2030 reflexions with I > 3-sigma(I). Both compounds contain a centrosymmetric dinuclear complex, [(DMSO)2Pt-(OH)2Pt(DMSO)2]2+, in which the platinum atoms are bridged by hydroxo ligands. Each Pt atom has a square-planar coordination with the DMSO molecules bonded to Pt through their S atoms. Both structures are stabilized by hydrogen bonds. Half-normal probability plot analyses of the geometry of the cation indicate that torsion and bond angles are significantly different in the two compounds. A similar comparison of the cation in the tetrafluoroborate compound and in the isostructural perchlorate compound (literature data) revealed that only the torsion angles are affected in this case.