Syntheses and characterization of complexes of copper(II) with Schiff-base ligands derived from 2,6-diacetylpyridine: spectroscopic, thermal behavior, magnetic moment and photoluminescent studies

Transition metal complexes derived from the Schiff base ligands are versatile compounds and playing vital role in organic light emitting diodes, medicinal and pharmaceutical fields due to their luminescent abilities and biological activities. Metal complexes of the two Schiff base ligands with Cu(II) ions were synthesized by reacting each ligand 2, 6-diacetylpyridine bis (benzoylhydrazone) (DAPBH) and 2, 6-diacetylpyridine bis (benzenesulfonylhydrazide) (DAPBSH) with the metal salts in refluxing ethanol. The compound DAPBH and DAPBSH reacted with copper(II) nitrates to provide the corresponding complexes A and B respectively. Both the ligands and complexes are characterized by UV-Visible spectroscopy, thermogravimetry, fourier transform infrared spectroscopy, photoluminescence spectra and scanning electron microscopy. Complexes A and B emit intense luminescence in solution, and a solvent dependent luminescent feature is found. In the solid state, complex B emits weak luminescence under 365 nm excitation from an ultraviolet lamp. Magnetic susceptibility measurements revealed that there are antiferromagnetic exchange interactions between the neighboring spins and IR studies confirm the existence of coordinated water molecules in the complex.