The water exchange mechanism in thorium (IV) hydrates as studied by quantum chemical methods

摘要

The water exchange mechanisms in [Th(H2O)(10)](4+) and [Th(H2O)(9)](4+) along dissociative (D), associative (A) and interchange (I) pathways have been investigated using the ab initio quantum mechanical calculations. Water exchange in [Th(H2O)(10)](4+) probably proceeds via the D mechanism, the activation energy is 3.06 kcal/mol. The Water exchange in [Th(H2O)(9)](4+) probably proceeds via the A pathway, the activation energy is 3.62 kcal/mol. Deprotonation of one coordinated water molecule of [Th(H2O)(10)](4+) leads to the formation of hydroxo-aquo complex [Th(OH)(H2O)(9)](3+), which has a more dissociative mechanism and lower activation energy. (C) 2003 Elsevier Science (USA). All rights reserved. [References: 18]