Synthesis, crystal structures and magnetic characterization of heterodinuclear CuIIGdIII and CuIITbIII Schiff base complexes

Preparation, crystal structures and magnetic properties of new heterodinuclear CuIIGdIII (1) and CuIITbIII (2) complexes [CuLn(L)(NO3)2(H2O)3MeOH]NO3·MeOH (where Ln = Gd, Tb) with the hexadentate Schiff-base compartmental ligand N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine (H2L = C19H20N2O4Br2) (0) have been described. Crystal structure analysis of 1 and 2 revealed that they are isostructural and form discrete dinuclear units with dihedral angle between the O1Cu1O2 and O1Gd1/Tb1O2 planes equal to 2.5(1)° and 2.6(1)°, respectively. The variable-temperature and variable-field magnetic measurements indicate that the metal centers in 1 and 2 are ferromagnetically coupled (J = 7.89 cm−1 for 1). Crystal and molecular structure of the Schiff base ligand (0) has been also reported. The complex formation changes the conformation of Schiff base ligand molecule.

The reaction of the hexadentate Schiff base ligand N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine (H2L) with Cu(II) and Gd(III)/Tb(III) yields the new heterodinuclear CuIIGdIII and CuIITbIII compounds having the general formula, [CuLn(L)(NO3)2(H2O)3MeOH]NO3·MeOH, (where Ln = Gd, Tb). The complexes have been characterized by the FTIR spectroscopy, X-ray crystallography and magnetic measurements.Figure optionsDownload as PowerPoint slideHighlights
► Heterodinuclear CuIIGdIII and CuII TbIII compounds.
► Ferromagnetic interaction between CuII and GdIII/TbIII ions.
► Correlation between JCuGd and the structure.