In this study, the formation constants (Kf) and thermodynamic functions (ΔH, ΔS) of the complexation reactions of the ligands 2,6-bis (6-methoxy-methylimino phenol) pyridine and bis-(phenolic) Schiff base with certain metal ions (Ag1+, Zn2+, Cu2+, Co2+, Cd2+, and Ni2+) in acetonitrile solvent were determined at different temperatures using conductometry and UV-Vis spectroscopy methods. In the conductometric method, a solution of metal ions with a concentration of 5×10-5 M was titrated stepwise with a ligand solution with a concentration of 5×10-3 M. After each addition of the ligand, the conductivity was recorded. These reactions were conducted at three constant temperatures: 15, 25, and 35 degrees Celsius. The molar conductivity (Λ) versus ligand-to-metal concentration ratio ([L]/[Mn+]) was plotted using Excel software, and the data obtained from the experiments were fitted using KINFIT software to determine the formation constants (Kf) of the complexes at different temperatures. Using the Van't Hoff equation, the thermodynamic functions (ΔH, ΔS) were calculated. In another section, using the UV-Vis spectroscopy method, a solution of the discussed metals with a concentration of 1.25×10-3 M was titrated with a ligand solution with a concentration of 5×10-5 M over 20 steps, and the corresponding spectra were plotted using Excel software. The absorption versus metal-to-ligand concentration ratio ([Mn+]/[L]) was plotted using Excel software, and the data obtained from the experiments were fitted using KINFIT software to determine the formation constants (Kf) of the discussed ligand complexes with each metal. The data obtained from both methods confirm each other.

Complex, 6-Methoxy-Methylimino Phenol, Pyridine Schiff Base, Bis-(Phenolic) Schiff Base