Solution Thermodynamics for the Thorium Complexation with <i>N</i>-(2-Hydroxyethyl) Iminodiacetic Acid

Sharma, S.D.; Dumpala, Rama Mohana Rao; Rawat, N.S.

doi:10.1021/acs.jced.9b00798

Cited by 9 publications

(11 citation statements)

References 48 publications

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“…The protonation of carboxylates is mainly driven by entropy with a very small contribution from enthalpy. The enthalpy and entropy changes for the first protonation are in agreement with the protonation of amine N, while the second protonation is in line with that of the carboxylate group …”

Section: Resultssupporting

confidence: 69%

“…Generally, the log K P values of aliphatic acids are around 4–5, However, for ADA, the electron-withdrawing effect of quaternary amine N as well as hydrogen-bonding interactions of quarternary amine H with carboxylate increases the acidity of carboxylic groups and decreases the log K P2 and log K P3 values to 2.09 and 1.04, respectively (Figure b,c). Among the other similar derivatives, viz., iminodiacetic acid (IDA), having hydrogen on amine N, and HEIDA, having the 2-hydroxyethyl functionality on amine N, the log K P1 values are in the order IDA > HEIDA > ADA, i.e., 9.29, 8.63, and 6.69, respectively. , The trend of log K P1 confirmed that the basicity of amine N is in the order IDA > HEIDA > ADA. The electron-withdrawing inductive effect of the substituent present on amine N reduces the charge density on the N atom and therefore lowers the basicity of amine.…”

Section: Resultsmentioning

confidence: 79%

“…The instrument was calibrated for pHc and standard electrode potential ( E 0 ) before titration experiments. The details of instrumentation and its calibration were given in our previous work . In potentiometric titrations, the concentration of H + ion is calculated at each point of titration by measuring the electromotive force (EMF) of the cell.…”

Section: Methodsmentioning

confidence: 99%

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Combined Thermodynamic, Theoretical, and Biological Study for Investigating N-(2-Acetamido)iminodiacetic Acid as a Potential Thorium Decorporation Agent

Sharma,

Ali,

Kumar

et al. 2023

Inorg. Chem.

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The most effective approach to mitigate the toxic effects of internal exposure of radiometals to humans is metal–ligand (ML) chelation therapy. Thorium (Th)-induced carcinogenesis as well as other health hazards to humans as a result of chronic internal exposure necessitates the development of efficient Th-decorporating agents. In this regard, chemical and biological studies were carried out to evaluate N-(2-Acetamido)iminodiacetic acid (ADA), a comparatively cost-effective, readily available, and biologically safe complexing agent for Th decorporation. In the present work, detailed thermodynamic studies for complexation of ADA with Th(IV) have been carried out to understand Th-ADA interaction, using potentiometry, calorimetry, electrospray ionization mass spectrometry, and theoretical studies, followed by its biological assessment for Th decorporation. Thermodynamic studies revealed the formation of strong Th-ADA complexes, which are enthalpically as well as entropically favored. Interestingly, density functional theory calculations, to obtain a thermodynamically favored mode of coordination, showed the uncommon trend of lower denticity of ADA in ML than in ML2, which has been explained on the basis of stabilization of ML by hydrogen bonding. The same was also reflected in the unusual trend of enthalpy for Th-ADA complexes. Biological experiments using human erythrocytes, whole human blood, and lung cells showed good cytocompatibility and ability of ADA to significantly prevent Th-induced hemolysis. Th removal of ADA from erythrocytes, human blood, and normal lung cells was found to be comparable with that of diethylenetriamine pentaacetate (DTPA), an FDA approved decorporating agent. The present study contributed significant data about Th complexation chemistry of ADA and its Th decorporation efficacy from human erythrocytes, blood, and lung cells.

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Section: Resultssupporting

confidence: 69%

Section: Resultsmentioning

confidence: 79%

Section: Methodsmentioning

confidence: 99%

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Combined Thermodynamic, Theoretical, and Biological Study for Investigating N-(2-Acetamido)iminodiacetic Acid as a Potential Thorium Decorporation Agent

Sharma,

Ali,

Kumar

et al. 2023

Inorg. Chem.

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“…The chemical nature of the participating ligand and the geometry arrived by its coordination on the equatorial plane has phenomenal effects on the intensities and positions of electronic transitions of the uranyl ion in the range of 380–480 nm arising from vibronic perturbed electronic transitions. , The protonation process is an inseparable mechanism while studying the complexation phenomenon, − especially with the protonated/deprotonated ligands; and the protonation thermodynamic data are a prerequisite to obtain the complexation thermodynamics data. The present studies utilized the protonation data from our previous work .…”

Section: Resultsmentioning

confidence: 99%

Chemical and Redox Speciation of Uranyl with Three Environmentally Relevant Bifunctional Chelates: Multi-Technique Approach Combined with Theoretical Estimations

et al. 2022

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Carbon and phosphorous are two primary elements common to the bio-geosphere and are omnipresent in both biotic and abiotic arenas. Phosphonate and carboxylate are considered as building blocks of glyphosate and humic substances and constituents of the cellular wall of bacteria and are the driving functionalities for most of the chemical interactions involving these two elements. Phosphonocarboxylates, a combination of both the functionalities in one moiety, are ideal models to dig deep into for understanding the chemical interactions of the two functional groups with metal ions. Phosphorous and carbon majorly exist as inorganic/organic phosphate and carboxylate, respectively, in the bio-geosphere. Aquatic contamination is a major concern for uranium, and the presence of complexing agents would alter the uranium concentrations in aquifers. Determination of solution thermodynamic parameters, speciation plots, redox patterns, E h −pH diagrams, coordination structures, and molecular-level understanding by density functional theory calculations was carried out to interpret the uranyl (UO 2 2+ ) interaction with three environmentally relevant phosphonocarboxylates, namely, phosphono-formic acid (PFA), phosphono-acetic acid (PAA), and phosphono-propanoic acid (PPA). UO 2 2+ forms 1:1 complexes with the three phosphonocarboxylates in the monoprotonated form, having nearly the same stability, and the complexes [UO 2 (PFAH)], [UO 2 (PAAH)], and [UO 2 (PPAH)] involve chelate formation of five, six, and seven membered rings, respectively, through the participation of an oxygen each from the carboxylate and phosphonate, strengthened by an intra-molecular hydrogen bonding through the proton of the phosphonate moiety with uranyl oxygen. The complex formations are favored both enthalpically and entropically, with the latter being more contributive to the overall free energy of formation. The redox speciation showed an aqueous soluble complex formation over a wide pH range of 1−8. Electrospray ionization mass spectrometry and extended X-ray absorption fine structure established the coordination modes, which are further corroborated by density functional calculations. The knowledge gained from the present studies provide potential inputs in framing the cleanup, sequestering, microbial, and bio-remediation strategies for uranyl from aquatic environments.

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“…All three phosphonocarboxylic acids have three dissociable protons (two on the phosphonate group and one on the carboxylate group). Oxygen atoms present in both the groups (phosphates and carboxylates) are hard donors and could bind with most of the metal ions to form stable minerals and complexes in solid as well as solution states. , The extent of protonation and deprotonation plays a crucial role in the interaction of the metal ion with organic moieties having dissociable protons. − Further, the complexation phenomenon is accompanied by the deprotonation of these ligands. Thus, the determination of the thermodynamic stability (as Δ G /log K ) and energetic balance (as Δ H and Δ S ) is a prerequisite for studying the metal–ligand interactions.…”

Section: Introductionmentioning

confidence: 99%

Protonation of Phosphonocarboxylates in Aqueous Medium: An Experimental and Theoretical Investigation

et al. 2022

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Phosphonates and carboxylates are two primitive functional groups omnipresent in nature, and they act as good chelators for metal ion binding. These two functional groups are always associated with dissociable protons in their acidic forms. Thus, their interactions are associated with protonation/deprotonation mechanisms. The present study was aimed at determining the thermodynamic parameters (log K P/pK a, ΔG P, ΔH P, and ΔS P) for the protonation of three aliphatic phosphonocarboxylates, namely, phosphonoformic acid (PFA), phosphonoacetic acid (PAA), and phosphonopropanoic acid (PPA), which differ in their spacer (connecting −CH2 moiety) length. Potentiometric and isothermal titration calorimetric studies were employed to determine the protonation constants (log K P/pK a) and enthalpies (ΔH P) of the three phosphonocarboxylates. All of the acids have three protonation sites ranging in pK a values from 1.8 to 7.4. The enthalpies of protonation are close to ±5 kJ/mol, except for the third protonation, and these protonations are mainly entropy-driven interactions. Density functional theory calculations were carried out to estimate interatomic distances and partial charges on all of the atoms to gain insights into the protonation mechanism at the molecular level. The predicted theoretical estimations followed the experimentally observed protonation trends.

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Solution Thermodynamics for the Thorium Complexation with N-(2-Hydroxyethyl) Iminodiacetic Acid

Cited by 9 publications

References 48 publications

Combined Thermodynamic, Theoretical, and Biological Study for Investigating N-(2-Acetamido)iminodiacetic Acid as a Potential Thorium Decorporation Agent

Combined Thermodynamic, Theoretical, and Biological Study for Investigating N-(2-Acetamido)iminodiacetic Acid as a Potential Thorium Decorporation Agent

Chemical and Redox Speciation of Uranyl with Three Environmentally Relevant Bifunctional Chelates: Multi-Technique Approach Combined with Theoretical Estimations

Protonation of Phosphonocarboxylates in Aqueous Medium: An Experimental and Theoretical Investigation

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