Speciation of uranium‐mandelic acid complexes using electrospray ionization mass spectrometry and density functional theory

Kumar, Pranaw; Jaison, P.G.; Telmore, Vijay M.; Sadhu, Biswajit; Sundararajan, Mahesh

doi:10.1002/rcm.7817

Cited by 11 publications

(5 citation statements)

References 43 publications

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“…In this regard, we considered a cyclic water cluster (pentamer) as the expelled moiety for the free-energy calculations (Table S1, Supporting information) . The choice of density functional for optimization (BP86) and single points (B3LYP) is based on prior investigations, which suggested that BP86 provides better structural properties (bond length, vibrational frequencies), while B3LYP is better for estimating the energetics with good accuracy. − We will demonstrate that BP86-optimized structures are indeed in excellent agreement with the available crystal structures. However, to be confident about the obtained trend in Δ G bind , an additional set of calculations was performed using two other density functionals for single points (BP86 and B2PLYP). …”

Section: Experimental Sectionmentioning

confidence: 89%

Role of O Substitution in Expanded Porphyrins on Uranyl Complexation: Orbital- and Density-Based Analyses

2021

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The need for efficient macrocyclic ligands that can sequester U(VI) has gained immense importance due to the increased applications of U(VI) in various sectors, including but not limited to nuclear energy. Structural attributes such as number and type of donor centers ("hard" and "soft") of ligands are essentially the key components for providing the adequate bonding scenario for uranyl. Beside hard or soft-donor-based binding cavity, the mixeddonor ligands are also finding popularity for achieving optimized performances. However, many aspects are still unknown about how and at what extent the ratio of hard-to-soft donor centers tune the bonding attributes with uranyl. Moreover, a consensus is yet to be reached on the nature and role of underlying covalent interaction between U and donors upon complexation, particularly in the mixed-donor ligand environment. In this work, using relativistic density functional theory (DFT), we attempted to address these important issues by systematically investigating the impact on the bonding characteristics of uranyl ion and an expanded porphyrin, viz. sapphyrin with increasing number of 'O' substitution at the cavity. Our results suggest that in the O-substituted sapphyrin variants, UO 2+ 2 prefers to bind N over O donor sites, and decrease in N donor sites at the cavity prompts UO 2+ 2 to have better interaction with the rest of N donor centers. Extended transition state (ETS)with natural orbital for chemical valences (NOCV) analysis shows that at equatorial plane N acts as better σ donor to uranyl than O donor. Molecular orbital (MO) and density of states (DOS) analysis shows favorable bonding-interaction between U(d) and donor's p orbitals, the participation of U(f)-orbitals in bonding are of low-extent but non-negligible. Energy decomposition analysis (EDA), natural population analysis (NPA) along with thermodynamic analyses confirms the dominance of electrostatic interaction on the thermodynamic stability of the complexes. However, the U-N/O bonds at the equatorial plane do carry appreciable amount of covalent character. Analysis of quantum theory of atoms in molecules (QTAIM) descriptors in conjugation with MO analysis and overlap integral calculations confirms its nature as near-degeneracy driven type. Statistics of mixed-orbitals and overlap integral fur-

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Section: Experimental Sectionmentioning

confidence: 89%

Role of O Substitution in Expanded Porphyrins on Uranyl Complexation: Orbital- and Density-Based Analyses

2021

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“…The pK a of HIBA is 3.8, whereas for mandelic acid, it is 3.4. 66,67 At pH 5.0, which is slightly higher than the pK a values of both acids, both will exist predominantly in their deprotonated forms. However, as mandelic acid has a lower pK a than HIBA, it will have a higher percentage of its molecules in the deprotonated form at pH 5.0.…”

Section: Aqueous Speciation and Complexation Stabilitymentioning

confidence: 97%

Thorium Complexation with Aliphatic and Aromatic Hydroxycarboxylates: A Combined Experimental and Theoretical Study

Kumar,

Dumpala,

Telmore

et al. 2024

ACS Omega

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“…The relative abundance of ML1 < ML2 < ML3 species in ESI-MS suggest a qualitative correlation between calculated free energies and observed complex relative stabilities. A similar approach was adopted to investigate the speciation of uraniummandelic acid complexes (Kumar et al, 2017) determining structures and free energies of the complexes that were in fair agreement with the ESI spectra. Based on the energetics of this latter study, the authors further predicted the formation of T-shaped dimeric uranyl complexes in the complexation process.…”

Section: Agmentioning

confidence: 99%

Recent Approaches for Chemical Speciation and Analysis by Electrospray Ionization (ESI) Mass Spectrometry

2021

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In recent years, the chemical speciation of several species has been increasingly monitored and investigated, employing electrospray ionization mass spectrometry (ESI-MS). This soft ionization technique gently desolvates weak metal–ligand complexes, taking them in the high vacuum sectors of mass spectrometric instrumentation. It is, thus, possible to collect information on their structure, energetics, and fragmentation pathways. For this reason, this technique is frequently chosen in a synergistic approach to investigate competitive ligand exchange-adsorption otherwise analyzed by cathodic stripping voltammetry (CLE-ACSV). ESI-MS analyses require a careful experimental design as measurement may face instrumental artifacts such as ESI adduct formation, fragmentation, and sometimes reduction reactions. Furthermore, ESI source differences of ionization efficiencies among the detected species can be misleading. In this mini-review are collected and critically reported the most recent approaches adopted to mitigate or eliminate these limitations and to show the potential of this analytical technique.

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Speciation of uranium‐mandelic acid complexes using electrospray ionization mass spectrometry and density functional theory

Cited by 11 publications

References 43 publications

Role of O Substitution in Expanded Porphyrins on Uranyl Complexation: Orbital- and Density-Based Analyses

Role of O Substitution in Expanded Porphyrins on Uranyl Complexation: Orbital- and Density-Based Analyses

Thorium Complexation with Aliphatic and Aromatic Hydroxycarboxylates: A Combined Experimental and Theoretical Study

Recent Approaches for Chemical Speciation and Analysis by Electrospray Ionization (ESI) Mass Spectrometry

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