In situ synthesis and dielectric properties of copper(II) and nickel(II) chiral Schiff base complexes

Two chiral Schiff base-containing complexes, [Cu(L¹)](ClO₄)₂·H₂O (1, L¹ = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L²)₂](ClO₄)₂ (2, L² = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO₄)₂·6H₂O or Ni(ClO₄)₂·6H₂O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L¹ and L² are bisubstituted and monosubstituted, respectively, corresponding to the different metal ions Cu^II and Ni^II. Variable-frequency and -temperature dielectric properties of 1 and 2 have been studied.