Journal article
Computational Investigation of the Chemical Bond between An(III) Ions and Soft-Donor Ligands
Inorganic chemistry, Vol.64(12), pp.5866-5877
03/31/2025
DOI: 10.1021/acs.inorgchem.4c03924
PMCID: PMC11962836
PMID: 40116360
Abstract
The chemical bonding of actinide ions with arene and borohydride ligands is explored via quantum chemical methods to understand how the transuranium elements interact with soft-donor ligands. Specifically, the
complexes (An = U, Np, and Pu) and their reduced congeners are studied. Density functional theory (DFT) shows that the metal-ligand interactions in the neutral complexes are governed by electrostatic interactions. Both DFT and complete active space (CASSCF) results show that as one moves from U to Pu, the 5f-orbitals are stabilized leading to a poorer energy match with the ligand orbitals. This contributes to progressively weaker metal-arene and metal-borohydride interactions across the series due to a decrease in energy-driven covalency. A reduction in orbital contributions to bonding is obtained for the transuranium-arene interactions as well. Upon reduction, the arene is reduced, forming a δ-bond. This causes the An-arene distances to contract by 0.1-0.2 Å compared to the neutral complexes. The ground state is assigned as the intermediate-spin state where the arene radical is antiferromagnetically coupled to the metal-centered f-electrons in Np and Pu. On the other hand, the ferromagnetically and antiferromagnetically coupled states are close in energy in the uranium complex, but do not mix when spin-orbit coupling is included using a state-interaction approach (SO-CASPT2). The population of the CASSCF δ*-antibonding natural orbital increases from U to Pu consistent with the increased An-arene distances, weaker interactions, and decreasing covalency across the series. Although the An-B distance increases by ca. 0.06 Å upon reduction, both the neutral and reduced species involve an An(III)-borohydride bond and as such are qualitatively similar. The Np complexes can be assigned to have slightly weaker bonding than the uranium analogs but are overall "uranium-like". The Pu complexes are predicted to have less covalent contributions to bonding in both the Pu-arene and Pu-borohydride interactions; however, the Pu-arene interaction is predicted to be particularly weak.
Details
- Title: Subtitle
- Computational Investigation of the Chemical Bond between An(III) Ions and Soft-Donor Ligands
- Creators
- Sabyasachi Roy Chowdhury - University of South DakotaNaomi Rehberg - University of South DakotaBess Vlaisavljevich - University of South Dakota
- Resource Type
- Journal article
- Publication Details
- Inorganic chemistry, Vol.64(12), pp.5866-5877
- DOI
- 10.1021/acs.inorgchem.4c03924
- PMID
- 40116360
- PMCID
- PMC11962836
- NLM abbreviation
- Inorg Chem
- ISSN
- 1520-510X
- eISSN
- 1520-510X
- Publisher
- American Chemical Society
- Grant note
- Basic Energy Sciences: DE-SC0025311 U.S. Department of Energy, Office of Science, Basic Energy Sciences, in the Heavy-Element Chemistry program: OAC-1626516 NSF
This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, in the Heavy-Element Chemistry program (Grant no. DE-SC0025311). Computations supporting this project were performed on High Performance Computing systems at the University of South Dakota, funded by NSF Award OAC-1626516. The authors thank Dr. Conrad Goodwin and Nathan Loutsch for valuable discussions.
- Language
- English
- Electronic publication date
- 03/21/2025
- Date published
- 03/31/2025
- Academic Unit
- Chemistry
- Record Identifier
- 9984801839502771