MAGNETOSTRUCTURAL CORRELATIONS IN LAYERED POLYMERIC MOLECULAR FERROMAGNETS BASED ON NI(II) AND CO(II) COMPLEXES WITH 3-IMIDAZOLINE NITROXIDE RADICALS AND METHANOL WITH DIFFERENT SUBSTITUENTS IN THE METAL CYCLE

We report on the synthesis, structure, and magnetic properties of Ni(I I) and Co(II) complexes with deprotonated enaminoketone derivatives of 3-imidazoline nitroxide radicals and methanol, ML(2)(CH3OH)(2). The c omplexes differ in substituents in the gamma-position of the donor ena minoketone group (Cl, H, CH3). When the substituents are varied, the m agnetic behavior of these exchange clusters and their capability for t hree-dimensional ordering of magnetic moments at 5-7 K are not altered , and the arrangement of polymer layers remains constant However, such variation of substituents is very important for the chemistry of thes e compounds. Thus the accepting ability of the central atom is reduced by substitution of the hydrogen atom by the methyl group but enhanced by substitution of halogen for hydrogen in the side chain of the enam inoketone. This favors a magnetic phase transition to a ferromagnetic state. The results obtained in this work are important for the chemica l design of molecular ferromagnets based on metal bischelates with par amagnetic ligands.