Equilibrium structures and energetics of various isomers of molecules with stoichiometry An·4O (An = Pu, Am, and Cm) are studied through electronic structure calculations at the relativistic density functional theory level in the frame of an accurate small-core pseudopotential model. In all cases, the global minima of the An·4O potential energy surfaces correspond to dioxo-superoxido-like species, [AnO2](O2). The stability of the "true" oxides AnO4 decreases from Pu to Cm, whereas the isomers with two O2 groups become relatively more stable. Correlation between the formal oxidation states and the Bader net charges of actinide atoms is discussed. Structural parameters, vibrational frequencies and charge and spin magnetization density distributions are analyzed in order to characterize the different isomers in chemical terms. Decrease of the An oxidation states along the An series is evident.
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http://dx.doi.org/10.1039/c4cp00235k | DOI Listing |
J Mol Graph Model
January 2025
"VINČA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, 11001, Belgrade, Serbia.
Technetium-99m plays a pivotal role in nuclear medicine, offering unique IMAGING capabilities due to its favorable physical and chemical properties. This study investigates the redox behavior and electronic structures of three representative Tc(V) oxo complexes, [TcO(HMPAO)], [TcO(Bicisate)], and [TcO(DMSA)], using computational techniques. Employing relativistic density functional theory with the Zero-Order Regular Approximation (ZORA), we analyze singlet-triplet energy gaps, Gibbs free energy changes, and redox potentials in neutral and acidic environments.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, United States.
ConspectusUnderstanding f element-ligand covalency is at the center of efforts to design new separations schemes for spent nuclear fuel, and is therefore of signficant fundamental and practical importance. Considerable effort has been invested into quantifying covalency in f element-ligand bonding. Over the past decade, numerous studies have employed a variety of techniques to study covalency, including XANES, EPR, and optical spectroscopies, as well as X-ray crystallography.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.
The chemical reactivity between benzene and the "naked" acyclic carbene-like (G13X) species, having two bulky N-heterocyclic boryloxy ligands at the Group 13 center, was theoretically assessed using density functional theory computations. Our theoretical studies show that (BX) preferentially undergoes C-H bond insertion with benzene, both kinetically and thermodynamically, whereas the (AlX) analogue favors a reversible [4 + 1] cycloaddition. Conversely, the heavier carbene analogues ((GaX), (InX), and (TlX)) are not expected to engage in a reaction with benzene.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
Within the framework of surface-adsorbate interactions relevant to chemical reactions of spent nuclear fuel, the study of actinide oxide systems remains one of the most challenging tasks at both the experimental and computational levels. Consequently, our understanding of the effect of their unique electronic configurations on surface reactions lags behind that of d-block oxides. To investigate the surface properties of this system, we present the first infrared spectroscopy analysis of carbon monoxide (CO) interaction with a monocrystalline actinide oxide, UO(111).
View Article and Find Full Text PDFMolecules
December 2024
Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 420088 Kazan, Russia.
In this study, comparative analysis of calculated and experimental C NMR shifts for a wide range of model platinum complexes showed that, on the whole, the theory reproduces the experimental data well. The chemical shifts of carbon atoms directly bonded to Pt can be calculated well only within the framework of the fully relativistic matrix Dirac-Kohn-Sham (mDKS) level ( = 0.9973, = 3.
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