Arylamine co-ordination complexes. Part IV. Complexes of nickel(II) thiocyanate with substituted anilines

Abstract

Complexes of the type Ni(aniline)_n(NCS)₂(n= 2, 4, and 6) are reported for a wide range of substituted anilines. The stable green 2 : 1 complexes have polymeric six-co-ordinate structures, and sulphur co-ordination by bridging thiocyanate produces splitting of the first and second electronic absorption bands, enabling estimates of the planar and axial ligand fields to be made. The NCS bending frequencies for bridging thiocyanate occur as a doublet in the range 450–490 cm^–1. With ortho-substituted anilines, only, blue complexes of the type Ni(amine)₄(NCS)₂, have also been obtained, with N-bonded anion. For para-substituted anilines only blue 6 : 1 complexes have also been isolated, and ionic structures of the type [Ni(amine)₆](NCS)₂ are suggested, rather than formulation as [Ni(amine)₄(NCS)₂](amine)₂, with lattice aniline.