Determination of the Stereochemistry of Manganese(II) Complexes by Electron Spin Resonance

THE determination of stereochemistry without recourse to X-ray diffraction is usually more difficult for complexes of manganese(II) than for those of many other transition metal ions, for the two methods traditionally used—electronic spectroscopy and magnetic measurements—give little information in this case. The magnetic moment of the high spin d 5 ion varies little from 5.92 B.M. Moreover, the d-d bands are spin-forbidden, so that they are very weak and difficult to observe, although it is sometimes possible to distinguish between 6 and 4-coordination.