N,N′-bis(5-bromo-2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropane Cu–4f–Cu and Cu–4f complexes: Synthesis, crystal structures and magnetic properties

Synthesis, crystal structures and magnetic studies of new heterotri- and heterodinuclear complexes having general formulae [Cu2Ln(L)2(NO3)(H2O)2](NO3)2·3H2O (where Ln = Ce (1), Pr (2), Nd (3) and La (4)), and [CuLn(L)(NO3)2(H2O)3MeOH]NO3·MeOH (where Ln = Dy (5) and Er (6)), respectively involving the Schiff base (H2L) as main ligand are reported. The heterotrinuclear complexes crystallize in the monoclinic space group C2/c with the molecule lying on the twofold axis (Z′ = 0.5), while the dinuclear complexes (5 and 6) form monoclinic crystals with space group P21/n. The lanthanide(III) cation in CuII–LnIII–CuII core is 10-coordinated, whereas in dinuclear compounds the coordination number for Ln(III) ion is only nine. The polyhedra formed around terminal Cu(II) ions in 1–3 have a shape of deformed tetragonal pyramid with water molecule in apical position. In crystals 5 and 6 the Cu(II) has octahedral coordination. The temperature dependence of the magnetic susceptibility and the field-dependent magnetization indicated that the interaction between CuII and LnIII ions is antiferromagnetic for Ln = Ce, Pr and Nd and ferromagnetic for Ln = Dy and Er.

Graphical abstractThe new heteronuclear complexes [Cu2Ln(L)2(NO3)(H2O)2](NO3)2·3H2O (where Ln = La, Ce, Pr, Nd) and [CuLn(L)(NO3)2(H2O)3MeOH]NO3·MeOH (where Ln = Dy, Er) with the Schiff base ligand N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine (H2L = C19H20N2O4Br2) have been synthesized. The complexes have been characterized by the FTIR spectroscopy, single crystal X-ray crystallography and magnetic measurements. The measurements of variable-temperature magnetic susceptibility revealed that CuII–LnIII–CuII (where Ln = Ce, Pr, Nd) exhibit antiferromagnetic interaction, whereas the metal centers in CuII–LnIII (where Ln = Dy, Er) are ferromagnetically coupled.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Heterotrinuclear CuIILnIIICuII (Ln = La, Ce, Pr, Nd) compounds. ► Heterodinuclear CuIILnIII (Ln = Dy, Er) compounds. ► Chiral two-blade propeller-like shape. ► Anti- and ferromagnetic interaction between CuII and LnIII ions.