Cu-Ln (Ln = Gd, Eu, Sm) Dinuclear Complexes Based on Schiff Base o-van-en Ligand: Syntheses, Crystal Structures, and Magnetic Properties.

Three new dinuclear complexes [CuCl(o-van-en)Ln(HO) Cl]Cl·CHO (Ln = Sm (1), Eu (2), Gd (3); H(o-van-en) is the Schiff base formed by 2/1 condensation of o-vanillin and ethylenediamine) were prepared in a single crystal form by the method of horizontal diffusion. The prepared complexes were characterized by chemical analyses and IR spectroscopy. The three complexes are isostructural and the Cu(II) is situated in the smaller cavities while the larger cavities accommodate larger Ln(III) atoms. The pentacoordination of the Cu(II) atoms is completed by a chlorido ligand in the apical position, while the octacoordination of the Ln(III) atoms is achieved by three additional aqua and one chlorido coligands. AC susceptibility studies have shown that complexes 2 and 3 exhibit field supported slow magnetic relaxation while complex 1 does not display AC activity.