Direct determination of zero-field splitting in Co(II) complexes by FAR infrared spectroscopy

Three centrosymmetric, mononuclear cobalt(II) complexes possessing large zero-field splitting parameter D have been studied by means temperature-dependent FAR infrared spectroscopy. From 15 temperature-dependent absorption peaks referring to the transition between the six lowest crystal-field multiplets the value of the D-parameter has been directly read off. These data are comparable with those values extracted by fitting the magnetic susceptibility and magnetization data.

Three mononuclear cobalt(II) complexes possessing large zero-field splitting parameter D ∼ 100 cm−1 have been studied by means temperature-dependent FAR infrared spectroscopy. From 15 temperature-dependent absorption peaks referring to the transitions between the six lowest crystal-field multiplets the value of the D-parameter has been directly read off. These data match the magnetometric determination.Figure optionsDownload as PowerPoint slideHighlights
► Mononuclear cobalt(II) complexes possess large zero-field splitting.
► Axial zero-field splitting parameter was detected using FAR infrared spectroscopy.
► The spectroscopic data are comparable with susceptibility and magnetization data.