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

Abstract

Three Salen-like gadolinium complexes, namely, mononuclear (4f) complex [{H 2 L}Gd(NO 3 ) 3 ] ( 1 ), heterodinuclear (3d–4f) complex [{LCu}Gd(NO 3 ) 3 ]·0.25H 2 O ( 2 ) and dimeric heterotrinuclear (3d–4f–3d′) complex [{LCu}Gd(H 2 O) 3 {Fe(CN) 6 }] 2 ·6H 2 O ( 3 ) [H 2 L = 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 H 2 L coordinates to gadolinium ion through O 2 O 2 moiety. Then, addition of Cu(Ac) 2 ·H 2 O to the mononuclear lanthanide complex yields expected heterodinuclear (3d–4f) complexes [{LCu}Gd(NO 3 ) 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.