New complexes of Ni(II) and Co(III) with a Schiff-base ligand derived from o -vanillin. Crystal structure, magnetic and catalytic properties of a dissymmetric binuclear nickel(II) complex

Abstract A binuclear complex, [Ni2L2(NO3)(H2O)(CH3CN)]ClO4·CH3CN (1), has been obtained using a Schiff-base ligand (HL) derived from o-vanillin and 4-(2-aminoethyl)morpholine. The crystal structure of 1 has been solved. Both Ni(II) ions are hexacoordinated, but they display different coordination spheres. The exchange interaction between the two nickel ions is antiferromagnetic (J = −7.9 ± 0.2 cm−1; H = −JS1S2), in line with the DFT calculations. Compound 1 has been tested as a catalyst in the epoxidation of various olefins. The reaction of the same ligand with a mixture of cobalt(II) perchlorate and nitrate affords a mononuclear Co(III) complex, [CoL2(H2O)]ClO4·CH3OH (2).