The vibrational spectrum of methyltrioxorhenium(VII)

Abstract

The inelastic neutron scattering and high-resolution FT-Raman spectra of methyltrioxorhenium are reported. Literature assignments of the modes below 1600 cm −1 are largely confirmed with the exceptions of the methyl torsion and the ReO 3 bending modes. The methyl torsion is observed for the first time at 200 cm −1, while the band at 230 cm −1 assigned previously to the torsion is shown to be a component of the factor group splitting of the solid. In the FT-Raman spectrum, the bands that derive from the E modes in the isolated molecule are split by the C s site symmetry of the crystal. This allows an unambiguous assignment of these modes to be made. On this basis, the assignment of the ReO 3 bending modes is reversed with the asymmetric mode at 325 cm −1 and the symmetric mode at 276 cm −1.