Journal
COMPUTATIONAL AND THEORETICAL CHEMISTRY
Volume 1118, Issue -, Pages 133-143Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.comptc.2017.09.002
Keywords
Actinide cations; DFT calculations; C-F bond activation; Reaction mechanisms
Categories
Funding
- Algerian government [CNEPRU B00L02 UN 1501 2013 0025]
Ask authors/readers for more resources
Investigations of the C-F bond activation by actinide monocation An(+) (An = Ac, Th, Pa, U, Np, Pu and Am) are carried out using relativistic density functional theory (OFF) computations. Originally, the aim of the study is to compare the ability of different actinide ions to break strong bonds particularly in the context of accidental radioactive dissemination. The An(+) reaction with the fluorinated hydrocarbon CH3F was selected as a representative system in this context. Unexpectedly, the considered An+ were found to react differently. Via linear transit (LT) and intrinsic reaction coordinate (IRC) calculations, three reaction mechanisms for the C-F bond activation, leading to the An-F+ formation, were revealed; the first one, i.e. 'harpoon' mechanism which was observed in the case of Pu+, Am+, while the second called 'inser tion-elimination' mechanism concerned the case of Th+, Pa+, U+ and Np+. OFT computations highlight the particular case of the Ac+ system which presents two different mechanisms according to its spin state: a mechanism qualified as 'harpoon-like' for the triplet state and an 'insertion-elimination' mechanism for the singlet state. The activation barrier for the fluorine elimination from CH3F is weak for all the studied systems, from 0.9 kcal/mol for Th+ to 8.2 kcal/mol for Am+. Th+ is found as the most effective ion to activate the C-F bond and a considerable exergonic character (-81.5 kcal/mol) for this reaction is expected. The performed orbital, population and charge analyses permitted to reveal the role of the actinide 7s, 6d and 5f orbitals and of electron transfers during the reaction. (C) 2017 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available