The Infrared Spectra of Cobalt(II) Halide Complexes with Trimethylphosphine Oxide (TMPO)

Abstract

Abstract The infrared spectra (4000–150 cm−1) of molecular complexes of cobalt(II) halides with trimethylphosphine oxide (TMPO), CoCl2.2TMPO, Cobr2.2TMPO and Col2.2TMPO, are investigated for polycrystalline samples. The band assignments for TMPO ligand fundamentals are made for a C3v local symmetry. The skeletal stretching vibrations are assigned in the 450–400 cm−1 region for μ(Co-O) and in the 320–150 cm−1 region for μ(Co-X). The frequency ratios μa(Co-X)/μs(Co-X) are compared with the ratios calculated from G matrix elements √Ga(Co-X)/Gs (Co-X) and result a tetrahedral geometry (C2v symmetry) for the CoX2O2 skeleton. The any characteristic infrared bands in this frequency region. From the relative intensities, the formers are attributable as μaCo-O and the latters as μsCo-O. The observed band positions are quite comparable with those reported for other TMPO complexes.