Magnetostructural study of tetracoordinate cobalt(II) complexes

Five tetracoordinate cobalt(II) complexes of the formula [CoX2L2] have been investigated by SQUID magnetometry; X is the (pseudo)halide ligand and L is the N- or P-donor ligand. The complexes exhibit a moderate magnetic anisotropy expressed by the zero-field splitting parameter D. Its value ranges as D/hc = −13 to + 5 cm 21 −1. The value of the D-parameter increases with the angular deformation δ that measures a deviation of the X–Co–X and L–Co–L angles with respect to the ideal tetrahedron.