Interactions of trivalent lanthanide cations with tetradentate Schiff bases. Synthesis and characterization of lanthanide(III) complexes with N,N′-bis(pyridin-2-ylmethylene)benzene-1,2-diamine

The novel lanthanide(III) complexes [La(NO3)3(H2O)L] 1, and [Ln(NO3)3L] (Ln=Pr 2, Sm 3, Gd 4) where L=N,N′-bis(pyridin-2-ylmethylene)benzene-1,2-diamine, have been obtained by direct reaction of the Schiff base ligand and the corresponding hydrated lanthanide(III) nitrates in methanol. All complexes were characterized spectroscopically and thermogravimetrically. Complex 3 was also characterized with crystallographic studies. In the molecular structure of 3, Sm(III) is surrounded by all four nitrogen atoms of the Schiff base and six oxygen atoms belonging to three bidentate chelating nitrato ligands.