Correlations between structure and magnetism of three N,N′-ethylene-bis(3-methoxysalicylideneimine) gadolinium complexes

Three Salen-like gadolinium complexes, namely, mononuclear (4f) complex [{H2L}Gd(NO3)(3)] (1), heterodinuclear (3d-4f) complex [{LCu}Gd(NO3)(3)]center dot 0.25H(2)O (2) and dimeric heterotrinuclear (3d-4f-3d') complex [(LCu)Gd(H2O)(3){Fe(CN)(6)}](2)center dot 6H(2)O (3) [H2L = N,N'-ethylene-bis(3-methoxysalicylideneimine)] have been synthesized by stepwise reactions. X-ray diffraction analysis reveals that 1 is of a discrete structure in which H2L coordinates to gadolinium ion through O2O2 moiety. Then, addition of Cu(Ac)(2)center dot H2O to the mononuclear lanthanide complex yields expected heterodinuclear (3d-4f) complexes [{LCu}Gd(NO3)(3)]. 3 features a unique 1D ladder-like topology structure through the intermolecular double links of Cu-N bonds. The measurement of variable-temperature magnetic susceptibility reveals that complex 1 exhibits antiferromagnetic interaction while 2 and 3 exhibit ferromagnetic interaction between spin carriers. The correlations between the structure and magnetism are described and discussed. (C) 2010 Published by Elsevier Masson SAS.