A tetradentate ligand, abbr. L2- =dmSALPD(2-) = N,N'-bis(sahcylidene)-1,3-propanediaminato dianion, has been complexed with metal ions in the presence of dimethylformamide (dmf) and nitrite anion. As a result, trinuclear molecular complexes of the type [M-II-{Ni(NO2(L2-)(dmf)}(2)], where M-II = Mn(II), Co(II) and Ni(II) were obtained. The magnetic susceptibility and magnetization data were treated simultaneously during the fitting procedure. In addition to the isotropic exchange, the zero-field splitting parameters D-A were added to the spin Hamiltonian. An anti-ferromagnetic interaction was found in all complexes and the single ion magnetic anisotropy parameter for the Ni(II) peripheral centers adopt considerable values. (c) 2006 Elsevier B.V. All rights reserved.