Catalytic Cleavage of the Amide Bond in Urea Using a Cobalt(III) Amino-Based Complex

The urease mimetic activity of Co^III amine complexes with respect to cleavage of urea was explored using SCXRD and spectroscopic techniques. The reaction of [Co^III(tren)Cl₂]Cl [tren = tris(2-aminoethyl)amine] with urea results in the formation of an isocyanato complex {[Co^III(tren)(NH₃)(NCO)]Cl₂} and ammonia, following the cleavage of the amide bond. The reaction progress and the subsequent formation of cleavage products were confirmed by SCXRD analysis of the reactants as well as the products obtained during the reaction. The reaction was found to be pH and temperature dependent, and the reaction conditions were optimized to maximize conversion. The reaction kinetics was followed spectroscopically (¹H NMR and UV/Vis), following the decrease in urea concentration or the increase in pH succeeding ammonia formation. A detailed kinetic study revealed an overall second order rate law and k_obs was found to be 3.89 × 10^–4 m^–1 s^–1.