A hexadentate nickel(II) complex with a tripodal ligand bearing S₃N₃ donors: synthesis, spectroscopic and X-ray crystal structural investigation

Abstract

A tripodal ligand, tris[2-(2-aminoethyl)thio]ethane (L¹), bearing three thioether sulphurs and three primary amino nitrogens has been synthesized in high yield. Reaction with nickel(II) perchlorate hexahydrate yielded the complex [Ni(L¹)](ClO)₄, which has been characterized by X-ray crystallography. The structure consists of two independent hexacoordinate cage cations and four independent perchlorate anions. The Ni^IIion is bound equatorially to two nitrogen and two sulphur atoms, while the other two donor atoms occupy the acial positions. Both the independent cage cations are disordered, with thioether sulphurs occupying two alternative sets of ligand sites. One of the four perchlorate anions is also disordered. IR, conductivity, RT magnetic susceptibility and electronic absorption spectral data are consistent with the solid state structure. The corresponding aromatic analogue, tris[2-(2-aminophenyl)thio]ethane (L²), forms the complex [Ni(L²)](ClO₄)₂, which has been characterized spectroscopically.