Resolving the π-assisted U-N σ-bond formation using quantum information theory

• Published in: Physical chemistry chemical physics : PCCP Vol. 24; no. 35; pp. 21296 - 2137
• Main Authors: Leszczyk, Aleksandra, Dome, Tibor, Tecmer, Pawe, Kedziera, Dariusz, Boguslawski, Katharina
• Format: Journal Article
• Published: 14.09.2022
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp03377a

We model the potential energy profiles of the UO 2 (NCO)Cl 2 − → NUOCl 2 − + CO 2 reaction pathway [Y. Gong, V. Vallet, M. del Carmen Michelini, D. Rios and J. K. Gibson, J. Phys. Chem. A , 2014, 118 , 325-330] using different pair coupled-cluster doubles (pCCD) methods. Specifically, we focus on pCCD and pCCD-tailored coupled cluster models in predicting relative energies for the various intermediates and transition states along the reaction coordinate. Furthermore, we augment our study on energetics with an orbital-pair correlation analysis of the complete reaction pathway that features two distinct paths. Our analysis of orbital correlations sheds new light on the formation and breaking of respective bonds between the uranium, oxygen, and nitrogen atoms along the reaction coordinates where the "yl" bond is broken and a nitrido compound formed. Specifically, the strengthening of the U-N σ f -bond is assisted by a π-type interaction that is delocalized over the C-N-U backbone of the UO 2 (NCO)Cl 2 − complex. pCCD-tailored coupled cluster theory predicts that the formation of the U-N σ-type bond is assisted by a weaker and delocalized π-type bond of the C-N-U backbone, leading to the breaking of the uranyl oxo bond and the formation of a nitride compound.