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

Two chiral Schiff base-containing complexes, [Cu(L-1)](ClO4)(2)center dot H2O (1, L-1 = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L-2)(2)](ClO4)(2) (2, L-2 = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (SS)-1,2-diaminocyclohexane and Cu(ClO4)(2)center dot 6H(2)O or Ni(ClO4)(2)center dot 6H(2)O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L-1 and L-2 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. (C) 2009 Elsevier B.V. All rights reserved.