Lanthanide(III) compounds with the N2O4-donor Schiff base – Synthesis, spectral, thermal, magnetic and luminescence properties

• Homonuclear Ln(III) complexes.
• Schiff base ligand.
• The crystal field effect.
• Photoluminescence studies.

New Schiff base complexes [Ln(NO3)3H2L] (where: Ln = Gd (1), Tb (2), Dy (3), Ho (4) and Er (5), H2L = N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine have been synthesized and characterized using elemental analysis, FTIR spectroscopy, thermogravimetric methods (TG–DSC), magnetic measurements, UV–Vis and luminescence studies. The compounds 1–5 follow the Curie–Weiss law all through the investigated temperature range 1.8–300 K. The 1 shows behavior characteristic for the well-isolated mononuclear system whereas the magnetic properties of 2–5 are dominated by the crystal field effect on the Ln(III) site, masking the magnetic interaction between the paramagnetic centers. The Tb(III) complex 2 emits the characteristic metal centered luminescence.