Heterometallic 3d-4f coordination polymers: Synthesis, characterization and magnetic properties of 1D zigzag chains containing samarium and terbium

Reaction of the copper precursor [Cu(MeOsaltn)(H(2)O)] (H(2)MeOsaltn=N,N'-bis(3-methoxysalicylidene)-1,3-diaminopropane) with Ln(NO(3))(3) center dot 6H(2)O (Ln = Sm and Tb) and pyrazine-2,3-dicarboxylic acid (H(2)Pyrdic) results in the formation of 1D zigzag chains with the general formula of [Cu(MeOsaltn)Ln(NO(3))(pyrdic)](n) center dot nDMF. X-ray crystal structures reveal that the samarium and terbium compounds are isostructural and crystalize in the orthorhombic space group Pbcn. The chains are composed of heterodinuclear copper-lanthanide building blocks which are linked by the pyrazine-2,3-dicarboxylate bridging units. Temperature-dependent susceptibility measurements indicate antiferromagnetic exchange interactions for the samarium-copper chain whereas for the terbium-copper compound ferromagnetic interactions are observed.