Two New Nickel(II) and Zirconium(IV) Schiff Base Complexes, Synthesis, Characterization and Luminescence Investigations

Schiff base ligands have been extensively studied in coordination chemistry mainly due to their facile syntheses, easily tunable steric, electronic properties, good solubility in common solvents and readily form stable complexes with most of the transition metals [1]. Multidentate Schiff bases have been widely used as ligands, because they can easily attached to metal ions due to the formation of high stability of coordination compounds. Also, the chemistry of transition metal complexes of Schiff bases has played an important role in the development of coordination chemistry as a whole. Metal complexes of S-, N-, and O-chelating ligands have attracted the considerable attention because of their interesting physico-chemical properties, pronounced biological activities and being models of metalloenzyme active sites [2]. In this research two new Schiff base complexes of nickel and zirconium have been synthesized by the reaction of Ni(OAc)2.4H2O and ZrCl4 with two moles of bidentate Schiff base ligand (containing a novel amine and 5-bromo-2-hydroxybenzaldehyd) at room temperature in methanol. In these complexes the ligands were coordinated to the metals via the imine N and enolic O atoms. The complexes have been found to possess 1:2 Metals:Ligands stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The emission spectra of the complexes were studied in acetone. The metal Schiff base complexes have been characterized by FT-IR, 1H NMR, UV/Vis, elemental analysis and conductometry