Insertion of FeII complexes with Schiff base ligands derived from imidazole or pyridine into 3D bimetallic oxalate-based ferromagnets

The syntheses, structures and magnetic properties of the compounds [Fe-II(imid(2)-trien)][Mn-II(CH3OH) Cr-III(ox)(3)](2)center dot(CH3OH)(4)(CH3CN)(H2O) (1), [Fe-II(tren(6-Me-py)(3))] [(MnCrIII)-Cr-II(ox)(3)][Mn-II(CH3OH)(0.58)(H2O)(0.42) Cr-III(ox)(3)]center dot(CH3OH)(2)(CH3CN)(0.5)(H2O)(0.42) (2) and [Fe-II(tren(imid)(3))](2)[Mn-2.5(CH3OH)(3)Cr-3(ox)(9)]center dot(CH3OH)(4.75). (H2O)(4.25) (3) are reported. They are prepared by the insertion of Fe-II-Schiff base complexes derived from imidazole and pyridine into bimetallic oxalate networks. Different types of 3D oxalate networks are obtained for each templating cation. Thus, [Fe-II(imid(2)-trien)](2+) and [Fe-II(tren(6-Me-py)(3))](2+) give rise to unusual 3D achiral bimetallic oxalate networks with heptacoordinated Mn-II ions in compounds 1 and 2, whereas a new type of chiral 3D oxalate network is obtained with [Fe-II(tren(imid)(3))](2+) in compound 3 that contains bis(bidentate) and terminal oxalate ligands. The magnetic properties indicate that they undergo a long-range ferromagnetic ordering around 5 K. The inserted cation presents a partial and gradual spin-crossover in 1 and 3. (C) 2013 Elsevier Ltd. All rights reserved.