Synthesis, characterization, crystal structures and magnetic properties of dissymmetrical double schiff base heterotrinuclear complexes: [CuL(H2O)CoCuL] <f>·</f> H2O <f>·</f> CH3OH and [(CuL)2Ni] <f>·</f> 2H2O

A dissymmetrical double Schiff base Cu(II) mononuclear complex: CuHL (1) (where H3L is N-3-carboxylsalicylidene-<f>N′</f>-salicylaldehyde-1,2-diaminoethane) and two trinuclear complexes: [CuL(H2O)CoCuL] <f>·</f> H2O <f>·</f> CH3OH (2) and [(CuL)2Ni] <f>·</f> 2H2O (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 O6 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. [Copyright &y& Elsevier]