Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen von Tetrahalogenooxalatoosmaten (IV), [OsX4(ox)]2-, X = Cl, Br, I / Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of Tetrahalogenooxalatoosmates (IV), [OsX4(ox)]2-, X = Cl, Br, I

Abstract

Abstract The crystal structures of [(C5H5N)2CH2][OsCl4(ox)] (monoclinic, space group I2/m, a = 10.260(5), b = 13.841(5), c = 12.273(5) Å, β = 92.050(5)°, Z = 4), [(C5H5N)2CH2][OsBr4(ox)]·H2O(monoclinic, space group P21/n, a = 11.666(3),b = 11.591(5), c = 14.926(2) Å, β = 102.45(2)°, Z = 4) and [P(C6H5)4]2 [OsI4(ox)]·2CH2Cl2 (triclinic, space group P1̄, a = 14.597(2), b = 11.9185(9), c = 22.5624(14) Å, α = 80.284(8), β = 78.903(8), γ = 69.432(8)°, Z = 2) have been determined by single crystal X-ray diffraction analysis. The IR and Raman spectra of the three complexes were measured at room temperature. Using the molecular parameters of the X-ray determinations normal coordinate analyses based on a modified valence force field have been performed and the normal modes of vibration are assigned. With a set of 25 force constants and taking into account the innerligand vibrations a good agreement between observed and calculated frequencies has been achieved. The valence force constants of the X-Os-X axis are fd(OsCl) = 1.77, fd(OsBr) = 1.48, fd(OsI) = 1.0 mdyn/Å, of the X′-Os-O• axes are fd(OsCl′) = 1.88, fd(OsBr′) = 1.6, fd(OsI′) =1.1 mdyn/Å and fd(OsO•) ranges from 2.7 to 2.8 mdyn/Å.