Abstract

The first purpose of this project was to spectroscopically study the relative reactivities of the halogen ligands chloride, bromide and iodide, by comparing their reactions with the cis- and trans-isomers of dinitrobisethylenediamine cobalt (III) nitrate in aqueous solution. The three halogen ligands were reacted by combining their acids with the isomers in distilled water and heating the resulting solution. The solution was then cooled and filtered to isolate the product. In the acid reactions the Cl^- produced a red shift in the UV-Vis spectra of the product. The other two anions, bromide and iodide, produced blue shifts. It is known that Br^- and I^- are more polarizable than Cl^-. The red and the blue shifts in the ultraviolet-visible spectra proved that the acids reacted with the isomers, producing new products. The two isomers were reacted with each of the three acids for 30 minutes and one hour to determine whether the reaction time affected the outcome. It was found that there was no difference between the 30 minute and hour reaction of any of the acids. The second purpose was to compare the strength of the ligands C₂H₃O₂^-, SCN^- and Br^-- based on their reactivities with the cis and trans-isomers in methanol. The three anion ligands were obtained by dissolving sodium and potassium salts in methanol. The methanol solution was heated to boiling at which point the isomers were added. The methanol reactions were run for 45 minutes each. The solutions were then hot filtered to eliminate the unreacted materials and the filtrate was crystallized and then filtered. In methanol, the only anion which replaced the nitrite ligand was C₂H₃O₂ ^-, and it did this only in the trans-isomer. In addition, it was concluded methanol is an effective solvent when the solute is an organic material.