Synthesis, characterization and the thermodynamic studies of some unsymmetrical tetradentate Schiff-base ligands and their Ni(II) and Cu(II) complexes

Abstract

Some new unsymmetrical tetradentate Schiff-base ligands, (N-salicylidene-N′-pyrrolidene)-1,2-ethylenediamine(H₂salpyren) (H₂L¹), (H₂Mesalpyren) (H₂L²), (H₂phsalpyren) (H₂L³), (N-salicylidene-N′-pyrrolidene)-1,3-propylenediamine (H₂salpyrpd) (H₂L⁴), (H₂Mesalpyrpd) (H₂L⁵), (H₂phsalpyrpd) (H₂L⁶) and their Ni(II) and Cu(II) complexes were synthesized and characterized by elemental analyses, IR, UV-Vis, ¹H NMR and mass spectra and magnetic moments. Possible structures of these complexes have been proposed. The thermodynamic formation constants of the complexes were determined spectrophotometrically at constant ionic strength 0.1 M (NaClO₄), at 25°C in methanol.

Keywords:

• Copper complex
• Formation constant
• Nickel complex
• Thermodynamics
• Unsymmetrical Schiff-base

Acknowledgement

We are grateful to the Shiraz University Research Council for its financial support.