The stability and chemical bonding of a series tridentate ligand-actinyl complexes: [AnO2(L)2]2+ (An: U and Am)

Zhang, Wenjing; Wang, Kai; Zhang, Ping; Hu, Shu‐Xian

doi:10.1016/j.molliq.2022.119118

Cited by 2 publications

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“…The 6d δ AOs interact with the 1a 1 and 1a 2 orbitals of [CHP] 4– or 1b 3g and 2a g orbitals of [AME] 4– to produce the 1b 1g and 1a g MOs of [UO 2 (L 6 )] 2– , and the 5f ϕ AOs along the U–N L bonding direction interact with the 2b 2 orbital of [CHP] 4– , yielding the 2b 2u MO. These MOs involve substantial mixing between the U and N L orbitals, yielding the larger splitting of 5f ϕ than that of 5f δ , with the [CHP] 4– having a larger separation that that of [AME] 4– , much as we showed in the calculations on uranyl-Phen systems. , Thus, the other 5f ϕ component and 5f δ AOs remain as nonbonding orbitals. In the 1 A g state of [UO 2 (L 6 )] 2– , the 1a g , 2a g , and 2b 2u MOs are completely filled, with the 2b 2u MO serving as the HOMO of these complexes.…”

Section: Resultssupporting

confidence: 56%

Trends in the Electronic Structure and Chemical Bonding of a Series of Porphyrinoid–Uranyl Complexes

Wang

Zhang

et al. 2023

Inorg. Chem.

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In this paper, we have explored the relativistic density functional theory study on a series of deprotonated porphyrinoid (L n ) complexes of uranyl to investigate the geometrical structures and chemical bonding. The ligands bound with uranyl in the 1:1 complexes [UO2(L n )] x (n = 4, 5, 6; x = 0, −1, −2), showing more thermodynamic stability for “in-cavity” structures of L5 and L6 than that of the “side-on” structure of L4 and an increase in stability with the increase of negative charges, L2– < L3– < L4–. Among the six ligands, the cyclo[6]pyrrole presents the best selectivity toward uranyl. Based on chemical bonding analyses, the U–NL bond in the in-cavity complexes adopts a typical dative NL → U bond with mainly ionic bonding and significant covalency, which comes from the significant orbital interaction of U 5fϕ6dδ7s hybrid AOs and NL 2p-based MOs. This work provides a systematic understanding of the coordination chemistry in uranyl pyrrole-containing macrocycle complexes and the nature of chemical bonding in such systems, which may provide inspirations for the future design of synthetic targets that could be relevant to actinide separations or in the remediation of spent nuclear fuel.

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Section: Resultssupporting

confidence: 56%

Trends in the Electronic Structure and Chemical Bonding of a Series of Porphyrinoid–Uranyl Complexes

Wang

Zhang

et al. 2023

Inorg. Chem.

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“…A similar An�O yl bond length elongation has previously been observed in other actinyl complexes to accommodate equatorial ligand coordination. 56,58 The relatively higher elongation in the latter points to better equatorial binding between the hexavalent actinyl cations and pyrrophen ligands. The An�O yl bond lengths decrease from uranyl to americyl, similar to the trend observed in their actinyl cations due to the actinide contraction across the 5f series.…”

Section: Structures and Vibrational Frequencies Of Actinyl (An(v/vi))...mentioning

confidence: 99%

Periodic Trends in the Stabilization of Actinyls in Their Higher Oxidation States Using Pyrrophen Ligands

Schreckenbach

Varathan

2023

Inorg. Chem.

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Owing to the prominent existence and unique chemistry of actinyls, their complexation with suitable ligands is of significant interest. The complexation of high-valent actinyl moieties (An = U, Np, Pu and Am) with the acyclic sal-porphyrin analogue called “pyrrophen” (L(1)) and its dimethyl derivative (L(2)) with four nitrogen and two oxygen donor atoms was studied using relativistic density functional theory. Based on the periodic trends, the [UVO2-L(1)/L(2)]1– complexes show shorter bond lengths and higher bond orders that increase across the series of pentavalent actinyl complexes mainly due to the localization of the 5f orbitals. Among the hexavalent complexes, the [UVIO2-L(1)/L(2)] complexes have the shortest bonds. Following the uranyl complex, due to the plutonium turn, the [AmVIO2-L(1)/L(2)] complexes exhibit comparable properties with those of the former. Charge analysis suggests the complexation to be facilitated through ligand-to-metal charge transfer (LMCT) mainly through σ donation. Thermodynamic feasibility of complexation was modeled using hydrated actinyl moieties in aqueous medium and was found to be spontaneous. The dimethylated pyrrophen (L(2)) shows higher magnitudes of thermodynamic parameters indicating increased feasibility compared to the unsubstituted ligand (L(1)). Energy decomposition analysis (EDA) along with extended transition-state-natural orbitals for chemical valence theory (ETS-NOCV) analysis shows that the dominant electrostatic contributions decrease across the series and are counteracted by Pauli repulsion. Slight but considerable covalency is provided to hexavalent actinyl complexes by orbital contributions; this was confirmed by molecular orbital (MO) analysis that suggests strong covalency in americyl (VI) complexes. In addition to the pentavalent and hexavalent actinyl moieties, heptavalent actinyl species of neptunyl, plutonyl, and americyl were studied. Beyond the influence of the charges, the geometric and electronic properties point to the stabilization of neptunyl (VII) in the pyrrophen ligand environment, while the others shift to a lower (+VI) and relatively stable OS on complexation.

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The stability and chemical bonding of a series tridentate ligand-actinyl complexes: [AnO2(L)2]2+ (An: U and Am)

Cited by 2 publications

References 52 publications

Trends in the Electronic Structure and Chemical Bonding of a Series of Porphyrinoid–Uranyl Complexes

Trends in the Electronic Structure and Chemical Bonding of a Series of Porphyrinoid–Uranyl Complexes

Periodic Trends in the Stabilization of Actinyls in Their Higher Oxidation States Using Pyrrophen Ligands

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