IEF-PCM Calculations of Absolute p<i>K</i><sub>a</sub> for Substituted Phenols in Dimethyl Sulfoxide and Acetonitrile Solutions

Trummal, Aleksander; Rummel, Alar; Lippmaa, É.; Burk, Peeter; Koppel, Ilmar A.

doi:10.1021/jp900750u

Cited by 46 publications

(48 citation statements)

References 37 publications

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“…78,79 The reliability of this method for pK a calculations has already been shown in earlier reports. 79 Both electrostatic and nonelectrostatic (i.e., cavitation, repulsion, and dispersion) terms were included in the calculation of ΔG solv values.…”

Section: Computational Sectionsupporting

confidence: 58%

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

Ganguly

2013

J. Phys. Chem. C

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This work reports that noncovalent interactions can be exploited to achieve hyperbasicity of a base. A new class of superbase has been identified using paracyclophane-based carbenes that possess a proton affinity (PA) value of 1251.4 kJ/mol at the M06-2X/6-311+G**//B3LYP/6-31+G* level of theory. Noncovalent interactions such as C−H + ···π and through-space π−π interactions amplify the basicity of such carbene systems by the stabilization of their protonated forms. These paracyclophane systems can be a suitable candidate for bis-protonation with the highest pK a (MeCN) value of 50.1 to date. The side phenyl ring in paracyclophane systems that is not directly involved in C−H + ···π type interactions contributes to augment the basicity by throughspace π−π interactions. The side ring of the paracyclophane system is involved in enhancement of the proton affinity of 19.3 kJ/mol via through-space π−π interaction. Molecular electrostatic potential (MESP) analysis shows that such noncovalent interactions can enhance the electron density at the reactive sites in suitably designed systems. The absolute minima of the MESP (V min ) located for these carbene systems correlate well with their calculated proton affinity values. The frontier molecular orbital energy differences (HOMO−LUMO) of such carbenes also correlate well with their proton affinity results. These paracyclophane-based carbene systems can be used for selective binding of lithium ions. Such lithium decorated systems can be exploited as a molecular container for the storage of multiple dihydrogen. This is the first example of the use of lithiated organic superbases as hydrogen storage material. The calculated conceptual density functional theory-based reactivity descriptors such as electronegativity, hardness, and electrophilicity indicate the stability of these H 2 trapped molecules. The calculated desorption energies per H 2 molecule (ΔE DE ) also indicate the recyclable property of the hydrogen storage materials.

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Section: Computational Sectionsupporting

confidence: 58%

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

Ganguly

2013

J. Phys. Chem. C

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“…In the present work, we used

Δ G_{solv, H^{+}}^{°}

value equal to −270.30 kcal/mol, which was obtained according to the following equation:

Δ G_{solv, H^{+}}^{°} = G_{normalg, H^{+}}^{°} + Δ G^{1 atm \to 1 normalM} + Δ G_{{_{solv,}}_{H} +}^{*},

where

G_{normalg, H^{+}}^{°}

is the standard free energy of proton in the gas phase; ΔG 1 atm→1 M = 1.89 kcal/mol is the contribution corresponding to the change of the standard state from 1 atm to 1 M; and

Δ G_{solv, H^{+}}^{*}

is the free energy of proton in the condensed phase and equal to −265.9 kcal/mol. The standard free energy of proton in the gas phase

G_{normalg, H^{+}}^{°}

equals −6.28 kcal/mol as found from the following equation:

G_{normalg, H^{+}}^{°} = H_{normalg, H^{+}}^{°} - {TS}_{g}^{°},

where

H_{normalg, H^{+}}^{°} = 5 / 2 italicRT = 1.48 kcal / mol

, and

S_{g}^{°} = 26.05 kcal / ((), mol normalK)

.…”

Section: Methodsmentioning

confidence: 93%

A theoretical quantitative estimation of acidity of uracil and its derivatives through the pK_a values

Ilyina

Khamitov

Мустафин

et al. 2018

J Chinese Chemical Soc

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In this paper, we propose a computational scheme for the theoretical estimation of gas‐phase acidity of uracil and its derivatives. The calculation of the acidities (рKа) of the compounds under study was performed using quantum chemical calculations with the composite G3MP2B3 method. The solvent effect was taken into account within the polarizable continuum model and density functional theory calculations by the Polarizable continuum model (solvate model density) ‐ the exchange functional of Tao, Perdew, Staroverov, and Scuseria method. We evaluated the influence of the nonspecific solvation using two approaches (single‐point calculations versus full optimization of the studied structures) and found that the use of full optimization of the geometry of the compound for calculating the solvent effect significantly enhances the accuracy of numerical estimation of the рKа values. The mean absolute deviation decreases by 0.60 and 0.37 units of рKа in the case of the single‐point and full‐optimization approaches, respectively. The most pronounced advantage of the latter approach is its universality. Indeed, because of the implicit accounting of solvation, this computational scheme may be applied to the calculations of the рKа values of any class of compounds without reservations. The proposed computational scheme for the estimation of acidity opens new opportunities for further studies in the field of acidity.

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“…Based on an analysis of the literature, [2][3][4][5][6][7] one may point out two terms of condensed phase modeling. The first term is connected to non-specific solvation covering, which is carried out in the frame of the continuum model of the solvent.…”

Section: Methods Of Solute-solvent Interaction Covering (Solvation Cormentioning

confidence: 99%

“…[4,5] However, some research shows very tight schemes oriented on the pK a estimation of a concrete set of compounds such as 5-substituted uracils [2] or phenols. [3] Methods of calculated data correction…”

Section: Methods Of Solute-solvent Interaction Covering (Solvation Cormentioning

confidence: 99%

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The pK_atheoretical estimation of C―H, N―H, O―H and S―H acids in dimethylsulfoxide solution

Хурсан

Ovchinnikov

2014

J. Phys. Org. Chem.

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A scheme for the pK a estimation of organic acids in dimethylsulfoxide (DMSO) solution based on quantum chemical calculations is proposed. The procedure of pK a calculation requires several steps. The first is the calculation of the gas phase acidity of the compound. The G3MP2B3, G4MP2 as well as CBS-QB3 composite methods made it possible to estimate values of gas phase acidities of an extensive set of structures with a high confidence level (standard deviations equal to 1.15, 1.13 and 1.29 kcal mol À1 , respectively; the test set included 91 compounds). The second step is the computation of the solvation correction with the integral equation formalism version of polarizable continuum model (IEF-PCM)-B3LYP/6-311+G(d,p) approximation. Within the bounds of our approach, the medium properties were covered only by the PCM model, i.e. the proposed procedure neglects specific interactions between DMSO and the solute. It was determined that the approach to pK a estimation mentioned above is the most balanced in terms of accuracy, resource intensity and computation time cost. In the third step, the error of the pK a calculation was decreased by correlation allowances. Correlation allowances were determined for each acid class (62 С-Н, 55 N-Н, 24 O-Н and 5 S-Н acids) in the range of 50 units in terms of logarithmic scale using the test set including 146 compounds. Seven O-H acids showing the ability to form cyclic dimers were separated into a discrete group. The proposed methodology was applied to the estimation of pK a for trans-and cis-dimethyl-4,5-dihydro-3H-pyrazol-3,5-dicarboxylates as well as for 5-fluorouracil subject to competitive dissociation, the latter by N1-H or N3-H bonds.

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IEF-PCM Calculations of Absolute pK_a for Substituted Phenols in Dimethyl Sulfoxide and Acetonitrile Solutions

Cited by 46 publications

References 37 publications

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

A theoretical quantitative estimation of acidity of uracil and its derivatives through the pK_a values

The pK_atheoretical estimation of C―H, N―H, O―H and S―H acids in dimethylsulfoxide solution

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IEF-PCM Calculations of Absolute pKa for Substituted Phenols in Dimethyl Sulfoxide and Acetonitrile Solutions

Cited by 46 publications

References 37 publications

In Silico Studies in Exploiting Weak Noncovalent C–H+···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

In Silico Studies in Exploiting Weak Noncovalent C–H+···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

A theoretical quantitative estimation of acidity of uracil and its derivatives through the pKa values

The pKatheoretical estimation of C―H, N―H, O―H and S―H acids in dimethylsulfoxide solution

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Product

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IEF-PCM Calculations of Absolute pK_a for Substituted Phenols in Dimethyl Sulfoxide and Acetonitrile Solutions

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

In Silico Studies in Exploiting Weak Noncovalent C–H⁺···π and π–π Interactions To Achieve Dual Properties: Hyperbasicity and Multiple Dihydrogen Storage Materials with Paracyclophane-Based Carbene Derivatives

A theoretical quantitative estimation of acidity of uracil and its derivatives through the pK_a values

The pK_atheoretical estimation of C―H, N―H, O―H and S―H acids in dimethylsulfoxide solution