Theoretical study on the mechanism of ure a hydroly sis catalyzed by Pd(II)

Four palladium(II ) aqua com plexes catalyze hydrolytic decomposition of urea into carbon dioxid e and ammo nia [۱]. The reaction catalyzed by [ Pd ( en )( H۲ O )۲ ] ۲ . Th e following steps in the mechanism of this rea ction are stu died experimentally by Kaminskaia and Kostic [۱]: bindin g of urea to the catal yst, formation of carbamic acid (H۲NCOOH ) coordinated to palladium(II) via the nitrogen atom, and conversion of this intermediate into carbon dioxide and ammonia. Although the simple palladium(II) complexes are very di fferent fro m the enzym e urease, w hich contains nickel(II) ions, the d ecompositi on of urea c atalyzed by both kinds of agents involves carbamic acid as the intermediate (rate determining step). I n this work, the mechanism of conversion of th is intermediate into carb on dioxide and ammonia has been studied usin g density functional m ethods. Mechanistic studies with metal comp lexes contribute to the understanding of the enzymatic mec hanism.

کلیدواژه ها:

Urea hydrolysis ، Mechanism ، Palladium ، Density functional theo ry