The Interaction of Nickel (II) Ion with Ethylene Diamine (en) Chelate Using Ethaline (Ionic Liquid) as a Solvent

For this experiment, this is the first time using 1 choline chloride (ChCl): 2 ethylene glycol (EG)based liquid (ethaline) to study the interaction between Ni (II) with ethylene diamine. Two of the optical methods for analyzing spectrophotometric measurements (continuous variations and molar ratio methods) have been utilized for determination of, the stoichiometry and whenever possible, the stability constants of the chelates formed. Job`s method was necessary to determine whether, the metal ion and the ligand ethylene diamine form one or more than one chelate, when more than one chelate formed, the results obtained depend on the maximum wavelength and for meaningful conclusions the wavelengths were carefully chosen. The empirical formulae of the chelates were further substantiated by the molar ratio method. The effect of time and temperature on the formation and stability of these chelates in solution is also investigated. The stability constants, K1, K2and K3 for the nickel (II) chelates were calculated by both optical methods, though reliable, and are comparable to literature values.