Quantum mechanical calculations of the interactions between diazacrowns and the sodium cation: an insight into Na<sup>+</sup> complexation in diazacrown-based synthetic ion channels

Skelton, Adam A.; Agrawal, Nikhil; Fried, Joel

doi:10.1039/c4ra14000a

Cited by 13 publications

(8 citation statements)

References 75 publications

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“…Molecular modeling is being widely used to predict the behavior and interactions among molecules . Quantum mechanical (QM) methods are used to provide the detailed interactions between a small subset of the real system or often two molecular species. − Researchers interested in using QM methods to calculate interactions at different pH values usually simulate the different protonation states and assume that at that pH a particular protonation state is dominant . In reality, there are fractions of protonated, deprotonated, and neutral species in a thermodynamic ensemble of a large number of molecules.…”

Section: Introductionmentioning

confidence: 99%

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

et al. 2018

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Herein, we present a theoretical model that combines classical pK a theory with quantum mechanical calculations to predict the extent of interaction between acid-/base-dependent species over a full range of pH conditions. To demonstrate the theoretical model, we have predicted the drug loading and release of a pH-responsive drug delivery system consisting of sulfasalazine, an anionic anti-inflammatory drug molecule, loaded onto the positively charged trimethylammonium (TA)-functionalized mesoporous silica nanoparticle surface. The model relies on the possible combinations of pH-dependent states of the surface (S) and drug (D) molecules as neutral (0) and deprotonated (−1) states, whose relative probabilities depend on their pK a value and the desired pH. The four possible combinations were identified as S0D0, S0D–1, S–1D0, and S–1D–1, and periodic density functional theory calculations were performed for systems comprising drug fragments adsorbed onto a model TA-functionalized quartz surface to calculate the pH-dependent interaction energy (E int pH). The E int pH value was attractive at the acidic environment of stomach (pH 2–5), where a drug is loaded and repulsive at neutral or slightly basic pH in the small intestine where it is released; the behavior is in accordance with the experimentally reported data. We also validated the experimental necessity of surface functionalization.

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Section: Introductionmentioning

confidence: 99%

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

et al. 2018

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“…The decreasing charge of metal cations shows that the charge transfer occurs between M-O or M-N https://scilett-fsg.uitm.edu.my/ Science Letters, 15(1): 90-100 (2021) ISSN: 1675-7785 eISSN: 2682-8626 Copyright © 2021 UiTM Press. DOI 10.24191/sl.v15i1.11798bonds[27][28]. This is a clear indication that the transfer of charges occurs at M-O/N bond, thus assured the ionic interaction at M-O, and M-N bonds[29].…”

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confidence: 88%

AIM and ELF bonding analyses of M–O and M–N (Metal= Ba, Y, Zr) in metal–complexes using DFT approach

2021

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The molecular interaction between the chelating agents of citric acid (CA), ethylenediaminetetraacetic acid (EDTA), and triethylenetetraamine (TETA) with metals (M = Ba, Y, and Zr) were studied using Density Functional Theory (DFT) method. This study aims to determine the type of bonding between M–O/N bonds in the CA/EDTA/TETA– complexes. In this study, each metal was attached at strategic positions of chelating agents and was optimized at B3LYP/6-31G* and UGBS level of theory. The M–O bonds were characterized based on Atoms–in–molecules (AIM) and Electron Localization Function (ELF) in the topological analysis. In AIM analysis, the total electron energy density at the bond critical point (BCP) of the M–O/N bonds are used to estimate the interaction involved. The low values of ρ(r) and positive values of ∇2ρ(r) indicates that ionic character exists in the M–O/N bonds. In ELF color-filled map, the blue shaded region between M–O/N atom acts as an indicator for the existence of the ionic interaction. Both AIM and ELF results confirm the existence of ionic bonding between M–O/N bonds, with values of ρ(r) and ∇2ρ(r) ranging from 0.02 to 0.12 au and 0.09 to 0.5 au respectively. Further analysis on charge distribution at M–O/N bonds show that the opposite charge between Ba, Y, and Zr with O/N assured the M– O/N ionic bonding interactions. Keywords: Density functional theory, metals, bonding, atom–in–molecules, bond critical point, electron localization functions

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“…The decreasing in charge can be attributed to the transfer of electrons from CA and EDTA to the metal. 39,40 The charge transfer in metal complexes is of utmost important as it influences the interaction between metal and chelating agent. It can be inferred that the greater the charge reduction in the metal the stronger the interaction in the metal complex.…”

Section: Mulliken Chargesmentioning

confidence: 99%

Binding Sites of Deprotonated Citric Acid and Ethylenediaminetetraacetic Acid in the Chelation with Ba2+, Y3+, and Zr4+ and Their Electronic Properties: a Density Functional Theory Study

Abdullah

Ang

2018

ACSi

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Density functional calculations were performed on the metal complexes formed during the synthesis of barium zirconate (BZY). This compound has been synthesized previously, but the molecular interactions present during the formation of the ligand-metal complexes are unknown. In this study, calculations were carried out to determine the preferred coordination sites for the metal complexes. The cations Ba 2+ , Y 3+ , and Zr 4+ were modeled to interact with two deprotonated chelating agents (citric acid [CA] and ethylenediaminetetraacetic acid [EDTA]) at strategic positions. Density functional theory (DFT) at the B3LYP level of theory with basis set 6-31G* and Universal Gaussian Basis Set (UGBS) was used. The relevant geometries, binding energies, and charge distributions of the complexes are reported. It was found that both CA and EDTA can bind the metal cations investigated in this study. Metal cations prefer to form bonds at the electron-rich sites of the chelating agents. Of the three metal cations considered, Zr 4+ was found to possess the strongest bonds to deprotonated CA and EDTA, followed by Y 3+ and then Ba 2+ .

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Quantum mechanical calculations of the interactions between diazacrowns and the sodium cation: an insight into Na⁺ complexation in diazacrown-based synthetic ion channels

Abstract: Quantum mechanical calculations were performed to study the conformational behavior and complexation between a sodium cation and a diazacrown (diaza-18-crown-6) using density functional theory (DFT), Møller–Plesset (MP2) and molecular mechanics methods.

Cited by 13 publications

References 75 publications

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

AIM and ELF bonding analyses of M–O and M–N (Metal= Ba, Y, Zr) in metal–complexes using DFT approach

Binding Sites of Deprotonated Citric Acid and Ethylenediaminetetraacetic Acid in the Chelation with Ba2+, Y3+, and Zr4+ and Their Electronic Properties: a Density Functional Theory Study

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Quantum mechanical calculations of the interactions between diazacrowns and the sodium cation: an insight into Na+ complexation in diazacrown-based synthetic ion channels

Abstract: Quantum mechanical calculations were performed to study the conformational behavior and complexation between a sodium cation and a diazacrown (diaza-18-crown-6) using density functional theory (DFT), Møller–Plesset (MP2) and molecular mechanics methods.

Cited by 13 publications

References 75 publications

Novel pKa/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

Novel pKa/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

AIM and ELF bonding analyses of M–O and M–N (Metal= Ba, Y, Zr) in metal–complexes using DFT approach

Binding Sites of Deprotonated Citric Acid and Ethylenediaminetetraacetic Acid in the Chelation with Ba2+, Y3+, and Zr4+ and Their Electronic Properties: a Density Functional Theory Study

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Quantum mechanical calculations of the interactions between diazacrowns and the sodium cation: an insight into Na⁺ complexation in diazacrown-based synthetic ion channels

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System

Novel pK_a/DFT-Based Theoretical Model for Predicting the Drug Loading and Release of a pH-Responsive Drug Delivery System