Density Functional Theory Analysis of the Importance of Coordination Geometry for 5f36d1 versus 5f4 Electron Configurations in U(II) Complexes

Justin C Wedal; Filipp Furche; William J Evans

doi:10.1021/acs.inorgchem.1c02161

Density Functional Theory Analysis of the Importance of Coordination Geometry for 5f³6d¹ versus 5f⁴ Electron Configurations in U(II) Complexes

Inorg Chem. 2021 Nov 1;60(21):16316-16325. doi: 10.1021/acs.inorgchem.1c02161. Epub 2021 Oct 13.

Authors

Justin C Wedal¹, Filipp Furche¹, William J Evans¹

Affiliation

¹ Department of Chemistry, University of California, Irvine, California 92697-2025, United States.

PMID: 34644069
DOI: 10.1021/acs.inorgchem.1c02161

Abstract

Density functional theory (DFT) calculations on four known and seven hypothetical U(II) complexes indicate the importance of coordination geometry in favoring 5f³6d¹ versus 5f⁴ electronic ground states. The known [Cp″₃U]^-, [Cp^tet₃U]^-, and [U(NR₂)₃]^- [Cp″ = C₅H₃(SiMe₃)₂, Cp^tet = C₅Me₄H, and R = SiMe₃] anions were found to have 5f³6d¹ ground states, while a 5f⁴ ground state was found for the known compound (NHAr^ⁱPr₆)₂U. The UV-visible spectra of the known 5f³6d¹ compounds were simulated via time-dependent DFT and are in qualitative agreement with the experimental spectra. For the hypothetical U(II) compounds, the 5f³6d¹ configuration is predicted for [U(CHR₂)₃]^-, [U(H₃BH)₃]^-, [U(OAr')₄]^2-, and [(C₈H₈)U]^2- (OAr' = O-C₆H₂^tBu₂-2,6-Me-4). In the case of [U(bnz')₄]^2- (bnz' = CH₂-C₆H₄^tBu-4), a 5f³ configuration with a ligand-based radical was found as the ground state.