Lanthanide compounds with particular magnetic properties

Abstract

Compartmental, potentially hepta- and hexa-dentate Schiff bases (H 4-L), have been obtained by the reaction of 3-formylsalicylic acid or 2,3-dihydroxybenzaldehyde with the polyamines NH 2-(CH 2) 2-X-(CH 2) 2-NH 2 ( X = NH, S, CH 3-(CH 2) 11 − ) or NH 2-R-NH 2 ( R = -( CH 2) 2-; -C(CH 3)2-CH 2-, -CH 2-C(CH 3) 2-CH 2-), respectively. Heptadentate ligands, which contain an inner N 2XO 2 and an outer O 2O 2 coordination chamber, form homo- and heterodinuclear lanthanide(III) complexes Ln 2( L)( X) 2· nH 2 O( X = Cl −, NO 3 −; n = 3–8). The hexadentate ligands have a smaller N 2O 2 inner compartment, capable of securing a d-transition but not a f metal ion, and the same O 2O 2 outer chamber. Consequently, mononuclear, M(H 2L) heterodinuclear MLn(H 2-L)(NO 3) 3 and heterotetranuclear [MLn(L)(NO 3)(S)] 2 complexes have been prepared. The properties of the complexes are discussed focusing the attention on the magnetic data. Digadolinium(III) complexes show an antiferromagnetic behaviour, while heteropolynuclear complexes containing copper(II) and gadolinium(III) show ferromagnetic interactions.