Structure of ruthenium complex in nitric acid solution estimated using DFT calculation

Kato, Akane* ; Kaneko, Masashi   ; Nakashima, Satoru*

Aiming to predict ruthenium spices in high-level radioactive liquid waste, we demonstrated to simulate the complexation reaction between nitrosylruthenium and nitrate ions. When comparing the thermodynamic stability of the twelve geometrical isomers of the nitrosylruthenium nitrate complexes, the complexes with nitrate ions at the equatrial position toward the Ru-NO axis were confirmed to be the most stable isomers. Moreover, the Gibbs free energies analysis of the stepwise complexation reactions indicated that the Gibbs energy difference was improved the dependency of the fraction of the ruthenium species on the nitrate ions concentration by considering the association energy between the complex and the substituting ligands.