The effect of anion-π interactions on the properties of pyrazinamide and some related compounds

Sarhadinia, S.; Ebrahimi, Ali

doi:10.1016/j.comptc.2017.12.003

Cited by 5 publications

(6 citation statements)

References 36 publications

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“…The Atoms in Molecules (AIM) method was used to analyze intermolecular hydrogen bond interactions using the electron density function [ρ(r)] and Laplacian [∇ 2 ρ(r)], which is crucial in understanding the nature of chemical bonding 47 . The ∇ 2 ρ (r) value at the BCP indicates electron density concentration, distinguishing between shared-shell and closed-shell bonding interactions.…”

Section: Resultsmentioning

confidence: 99%

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules

Shiroudi,

Śmiechowski,

Czub

et al. 2024

Sci Rep

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The study investigates the molecular structure of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its derivatives in the gas phase using B3LYP and M06-2X functional methods. Intermolecular interactions are analyzed using natural bond orbital (NBO) and atoms in molecules (AIM) techniques. NO2-substituted TEMPO displays high reactivity, less stability, and softer properties. The study reveals that the stability of TEMPO derivatives is mainly influenced by LP(e) → σ∗ electronic delocalization effects, with the highest stabilization observed on the oxygen atom of the nitroxide moiety. This work also considers electron density, atomic charges, and energetic and thermodynamic properties of the studied NO radicals, and their relative stability. The proton affinity and gas-phase basicity of the studied compounds were computed at T = 298 K for O-protonation and N-protonation, respectively. The studied DFT method calculations show that O-protonation is more stable than N-protonation, with an energy difference of 16.64–20.77 kcal/mol (22.80–25.68 kcal/mol) at the B3LYP (M06-2X) method. The AIM analysis reveals that the N–O…H interaction in H2O complexes has the most favorable hydrogen bond energy computed at bond critical points (3, − 1), and the planar configurations of TEMPO derivatives exhibit the highest EHB values. This indicates stronger hydrogen bonding interactions between the N–O group and water molecules.

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Section: Resultsmentioning

confidence: 99%

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules

Shiroudi,

Śmiechowski,

Czub

et al. 2024

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The Atoms in Molecules (AIM) method was used to analyze intermolecular hydrogen bond interactions using the electron density function [ρ(r)] and Laplacian [∇ 2 ρ(r)], which is crucial in understanding the nature of chemical bonding. 40 The ∇ 2 ρ(r) value at the BCP indicates electron density concentration, distinguishing between shared-shell and closed-shell bonding interactions.…”

Section: Characterization Of Chemical Bondsmentioning

confidence: 99%

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives, and their hydrogen bonding interactions with water molecules

Shiroudi,

Śmiechowski,

Czub

et al. 2024

Preprint

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The molecular structure of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its derivatives (X: CH3, NH2, CHO, and NO2) in the gas phase, as well as their hydration, is investigated using the B3LYP method and the 6-311 + + G(d,p) basis set. Intermolecular interactions are analyzed using the natural bond orbital (NBO) and atoms in molecules (AIM) techniques. NBO analysis reveals the stability and formation of compounds, while AIM calculations show all hydrogen bonding interactions in the hydrated forms of TEMPO derivatives. The chemical reactivity parameters show that NO2-substituted TEMPO, with a small HOMO-LUMO energy gap, is more reactive, less stable, and exhibits softer qualities. Furthermore, the NBO results show that the stability of the investigated TEMPO derivatives is mainly influenced by LP(e)→σ∗ electronic delocalization effects, with the highest stabilization observed on the oxygen atom of the nitroxide moiety. The study considers electron density, atomic charges, and energetic and thermodynamic properties of the studied nitroxide radicals and their relative stability. The study computed the proton affinity (PA) and gas-phase basicity (GB) of TEMPO derivatives at T = 298 K for the O-protonation and N-protonation.The computed PA values in case of O-protonation of TEMPO derivatives (X: H, CH3, NH2, CHO, NO2) are 896.04, 894.17, 892.57, 870.36, and 851.29 kJ/mol, respectively, while the corresponding values for N-protonation are 806.50, 806.92, 804.08, 787.45, and 763.11 kJ/mol, respectively. The AIM analysis reveals that the N−O…H interaction in H2O complexes has the most favorable H-bond energy. The electronic structure characterization of N−O…H bonds in stable conformers of studied TEMPO derivatives revealed H-bond energies of 6.90, 6.90, 6.87, 6.62, and 6.46 kcal/mol for H, CH3, NH2, CHO, and NO2 substitutions, computed at bond critical points (3,−1).

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“…8,9 As the experimental measurement of the PAs and GBs is difficult, the computation methods have witnessed a great interest last few decades. [10][11][12][13][14][15][16] DFT methods with a large and rational basis set can reproduce a reliable thermochemical and thermodynamic properties for chemical systems. [10][11][12][16][17][18] Previous studies showed that PA and GBs values calculated using the B3LYP method are as efficient possible as high-level ab initio results.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, wide experimental and theoretical efforts were attained to calculate the PA and GB values, especially in gas phase, for example, ion mobility spectrometry (IMS), 5 mass spectrometry (MS), 6,7 calorimetry, kinetic method and ion cyclotron resonance (ICR) mehods 8,9 . As the experimental measurement of the PAs and GBs is difficult, the computation methods have witnessed a great interest last few decades 10–16 . DFT methods with a large and rational basis set can reproduce a reliable thermochemical and thermodynamic properties for chemical systems 10–12,16–18 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Benchmark calculations of proton affinity and gas‐phase basicity using multilevel (G4 and G3B3), B3LYP and MP2 computational methods of para‐substituted benzaldehyde compounds

Safi

Wazzan

2021

J Comput Chem

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This study presents the benchmark calculations of proton affinities (PAs) and gas-phase basicities (GBs) of 8-para substituted benzaldehyde compounds using the multilevel model chemistries (G3B3 and G4), density-functional quantum model (B3LYP) and ab initio model (MP2). The results show that the computed properties are strongly correlated with the available experimental data. The PAs and the GBs of other eight para-substituted benzaldehyde compounds, for which the experimental data does not currently exist, have been calculated using G3B3 and B3LYP methods.

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The effect of anion-π interactions on the properties of pyrazinamide and some related compounds

Cited by 5 publications

References 36 publications

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules

Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives, and their hydrogen bonding interactions with water molecules

Benchmark calculations of proton affinity and gas‐phase basicity using multilevel (G4 and G3B3), B3LYP and MP2 computational methods of para‐substituted benzaldehyde compounds

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