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Title: A Combined Density Functional Theory and Spectrophotometry Study of the Bonding Interactions of [NpO 2·M] 4+ Cation–Cation Complexes

The equilibrium constants for [NpO 2M∙] 4+ (M = Al 3+, In 3+, Sc 3+, Fe 3+) in μ = 10 M nitric acid and [NpO 2∙Ga] 4+ in μ = 10 M hydrochloric acid media have been determined. The trend in the interaction strength follows: Fe 3+ > Sc 3+ In 3+ > Ga 3+ Al 3+. These equilibrium constants are compared to those of previously reported values for NpO 2 + complexes with Cr 3+ and Rh 3+ within the literature. Thermodynamic parameters and bonding modes are discussed, with density functional theory and natural bond orbital analysis indicating that the NpO 2 + dioxocation acts as a -donor with transition-metal cations and a sigma donor with group 13 cations. The small changes in electron-donating ability is modulated by the overlap with the coordinating metal ion's valence atomic orbitals.
ORCiD logo [1] ;  [1] ; ORCiD logo [2] ;  [1] ;  [1]
  1. Washington State Univ., Pullman, WA (United States). Dept. of Chemistry
  2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; SC0001815
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 56; Journal Issue: 9; Journal ID: ISSN 0020-1669
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cation-cation; neptunium; high ionic strength; spectrophotometry; density functional theory
OSTI Identifier: