Synthesis, characterization, crystal structures and magnetic properties of dissymmetrical double schiff base heterotrinuclear complexes:: [CuL(H2O)CoCuL] • H2OCH3OH and [(CuL)2Ni]•2H2O

A dissymmetrical double Schiff base Cu(II) mononuclear complex: CuHL (1) (where H3L is N-3-carboxylsalicylidene-N'-saiicylaldehyde- 1,2-diaminoethane) and two trinuclear complexes: [CuL(H2O)CoCuL] (.) H2O (.) CH3OH (2) and [(CuL)(2)Ni](.) 2H(2)O (3) have been synthesized and characterized by means of elemental analyses, IR and electronic spectra. The crystal structures of two heterotrinucler complexes were determined by X-ray analysis. Each dissymmetrical cell unit of the complex 2 contains two heterotrinucler neutral molecules. In each neutral molecule, the central CO2+. ion is located at the site Of 06 with a distorted octahedral geometry and one terminal Cu2+ ion at the four-coordination site of N2O2, but the other one at the square-pyramidal environment of N2O3. Each dissymmetrical unit of the complex 3 contains a heterotrinucler neutral molecule, whose structure is similar to that of 2 except two terminal Cu2+ ions both at the inner site of N2O2. The magnetic properties of two heterotrinucler complexes have been determined in the temperature range of 5-300 K, which indicate that the interaction between the central Co2+ ion or Ni2+ ion and the outer Cu2- ions is antiferromagnetic. The exchange integrals are equal to -26.2 cm(-1) for 2 and -50.6 cm(-1) for 3. (C) 2004 Elsevier B.V. All rights reserved.