Theoretical study on thermochemical parameters and pKa values for fluorinated isomers of toluene

Zanganeh, Jafar; Altarawneh, Mohammednoor; Saraireh, Ibrahim A. M.; Namazi, Samira; Zanganeh, Javad

doi:10.1016/j.comptc.2013.02.003

Cited by 7 publications

(5 citation statements)

References 23 publications

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“…In this region (termed the "echo-limited regime"), relaxivity decreases as cluster size increases. 22 In our study, SPIONs immobilized on PLGA nanoparticles demonstrate higher relaxivity than SPIONs immobilized on PLGA microparticles. We propose that the SPION-coated PLGA nanoparticles are near the optimum relaxivity associated with the static dephasing regime, and that further increases of the SPION-PLGA carrier size will decrease relaxivity.…”

Section: Resultsmentioning

confidence: 49%

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Lee

Clay

et al. 2018

Langmuir

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Superparamagnetic iron oxide nanoparticles (SPIONs) are often encapsulated into drug-carrying nano/microsized particles for simultaneous magnetic resonance (MR) imaging and treatment of diseased tissues. Unfortunately, encapsulated SPIONs may have a limited ability to modulate the T 2 -weighted relaxation of water protons, but this insight has not been examined systematically.This study demonstrates that SPIONs immobilized on 200 nm diameter poly(lactic-co-glycolic acid) (PLGA) nanoparticles using Pickering emulsification present 18-fold higher relaxivity than encapsulated SPIONs and 1.5-fold higher relaxivity than free SPIONs.

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Section: Resultsmentioning

confidence: 49%

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Lee

Clay

et al. 2018

Langmuir

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“…We treat the internal rotations in aniline and all derived species that involve the amine group as hindered rotors with the overall enthalpy barrier of 23.2 kJ/mol. The rotation enthalpy of the NH 2 group is derived from a recent estimate of Zanganeh et al Finally, the DMol code facilitates the calculations of the Hirshfeld atomic charges and the Fukui ( f 1 ) indices . The Fukui indices indicate the tendency of a molecular site to undergo an electrophilic addition.…”

Section: Methodsmentioning

confidence: 99%

Reaction of Aniline with Singlet Oxygen (O₂ ¹Δ_g)

et al. 2017

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Dissolved organic matter (DOM) acts as an effective photochemical sensitizer that produces the singlet delta state of molecular oxygen (OΔ), a powerful oxidizer that removes aniline from aqueous solutions. However, the exact mode of this reaction, the p- to o-iminobenzoquinone ratio, and the selectivity of one over the other remain largely speculative. This contribution resolves these uncertainties. We report, for the first time, a comprehensive mechanistic and kinetic account of the oxidation of aniline with the singlet delta oxygen using B3LYP and M06 functionals in both gas and aqueous phases. Reaction mechanisms have been mapped out at E, H, and G scales. The 1,4-cycloaddition of OΔ to aniline forms a 1,4-peroxide intermediate (M1), which isomerizes via a closed-shell mechanism to generate a p-iminobenzoquinone molecule. On the other hand, the OΔ ene-type reaction forms an o-iminobenzoquinone product when the hydroperoxyl bond breaks, splitting hydroxyl from the 1,2-hydroperoxide (M3) moiety. The gas-phase model predicts the formation of both p- and o-iminobenzoquinones. In the latter model, the M1 adduct displays the selectivity of up to 96%. A water-solvation model predicts that M1 decomposes further, forming only p-iminobenzoquinone with a rate constant of k = 1.85 × 10 (L/(mol s)) at T = 313 K. These results corroborate the recent experimental findings of product concentration profile in which p-iminobenzoquinonine represents the only detected product.

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“…This procedure relies on the calculation of a limited number of points on the potential energy surface. Mostly, a thermodynamic cycle is used and the only empirical input is the aqueous solvation free energy of the proton . It was previously shown that adding explicit solvent molecules inside the cavity can improve the accuracy of calculated p K a values, although it is challenging to determine the necessary amount of water molecules …”

Section: Introductionmentioning

confidence: 99%

“…Mostly, at hermodynamic cycle is used and the only empirical input is the aqueous solvationf ree energy of the proton. [20][21][22][23][24][25][26] It was previously shown that adding explicit solvent molecules inside the cavity can improve the accuracyo fc alculated pK a values, although it is challenging to determine the necessary amount of water molecules. [27][28][29][30][31][32][33] To treat more complex molecular environments, such as polymericm aterials, one needs to go beyondc ontinuumt echniques.…”

Section: Introductionmentioning

confidence: 99%

Acidity Constant (pK_a) Calculation of Large Solvated Dye Molecules: Evaluation of Two Advanced Molecular Dynamics Methods

et al. 2016

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AbstractpH‐Sensitive dyes are increasingly applied on polymer substrates for the creation of novel sensor materials. Recently, these dye molecules were modified to form a covalent bond with the polymer host. This had a large influence on the pH‐sensitive properties, in particular on the acidity constant (pK a). Obtaining molecular control over the factors that influence the pK a value is mandatory for the future intelligent design of sensor materials. Herein, we show that advanced molecular dynamics (MD) methods have reached the level at which the pK a values of large solvated dye molecules can be predicted with high accuracy. Two MD methods were used in this work: steered or restrained MD and the insertion/deletion scheme. Both were first calibrated on a set of phenol derivatives and afterwards applied to the dye molecule bromothymol blue. Excellent agreement with experimental values was obtained, which opens perspectives for using these methods for designing dye molecules.

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Theoretical study on thermochemical parameters and pKa values for fluorinated isomers of toluene

Cited by 7 publications

References 23 publications

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Reaction of Aniline with Singlet Oxygen (O₂ ¹Δ_g)

Acidity Constant (pK_a) Calculation of Large Solvated Dye Molecules: Evaluation of Two Advanced Molecular Dynamics Methods

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Theoretical study on thermochemical parameters and pKa values for fluorinated isomers of toluene

Cited by 7 publications

References 23 publications

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Spatial Organization of Superparamagnetic Iron Oxide Nanoparticles in/on Nano/Microsized Carriers Modulates the Magnetic Resonance Signal

Reaction of Aniline with Singlet Oxygen (O2 1Δg)

Acidity Constant (pKa) Calculation of Large Solvated Dye Molecules: Evaluation of Two Advanced Molecular Dynamics Methods

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Reaction of Aniline with Singlet Oxygen (O₂ ¹Δ_g)

Acidity Constant (pK_a) Calculation of Large Solvated Dye Molecules: Evaluation of Two Advanced Molecular Dynamics Methods