Synthesis and characterization of CuII–LnIII (Ln = Ho, Tm, Yb, or Lu) complexes with N2O4-donor Schiff base ligand

The heterodinuclear complexes [CuLnL(NO3)2(H2O)3MeOH]NO3·MeOH (Ln = Ho (1), Tm (2), Yb (3), and Lu (4); L = N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine) have been synthesized and characterized by elemental analysis, FTIR, thermogravimetric (TG)/differential scanning calorimetry (DSC), TG-FTIR, single crystal X-ray diffraction studies, and magnetic measurements. The isostructural compounds crystallized in the monoclinic space group P21/n. The rare earth(III) cation is nine coordinate, whereas the coordination number for copper(II) is six. The complexes were stable at room temperature. The thermal decomposition products were mainly CH3OH, H2O, CH3Br, NOx (x = 1 or 2), CO2, and CO. The magnetic properties of 1–3 were dominated by the crystal field effect on the LnIII site, masking the magnetic interaction between the paramagnetic centers. The CuII–LuIII pair in 4 showed no significant interaction, which is in accord with the diamagnetic nature of the ground state for lutetium(III).