Arylamine co-ordination complexes. Part II. Tetragonally distorted nickel(II) complexes containing co-ordinated perchlorate

Abstract

The preparation and properties of a series of paramagnetic complexes of nickel(II) perchlorate with substituted anilines are described. Magnetic and spectral data show that most of these complexes have tetragonal structures of the type [Ni(amine)₄(ClO₄)₂], containing unidentate perchlorate groups. Attempts have been made to correlate the extent of tetragonal distortion, as measured by the splitting of the first spin-allowed electronic absorption band, with various parameters of the complexes and amines. The axial crystal-field parameter, 10Dq^z, for the perchlorate group is not constant in this series of complexes, but decreases as the planar field 10Dq^xy, due to the aniline ligands, increases. Anilines with methyl- or chloro-groups in the ortho-position seem to sterically hinder co-ordination by the axial perchlorate groups, giving unusually low values of 10Dq^z.

Some ionic complexes of the types [Ni(amine)_n](ClO₄)₂, (n= 4 or 6) are reported. Those with n= 4 contain ortho-alkoxy groups.