Molecular structure and electron distribution of 4-nitropyridine N-oxide: Experimental and theoretical study of substituent effects

Belova, N. V.; Pimenov, Oleg A.; Kotova, Vitaliya E.; Girichev, G. V.

doi:10.1016/j.molstruc.2020.128476

Cited by 9 publications

(6 citation statements)

References 44 publications

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“…If the laplacian at a point is positive, that means the average of that point's neighbour's values is greater than the value at that point and if it is negative, the neighbour's value is lower than the value of that point. It was also shown that, laplacian electron density for NU/POM(NO 2 ) systems had the lowest value that was the only negative recorded (−0.0650) and with the highest electronic energy density (−0.1284) which indicate the occurrence of shared interaction, thus implies the covalent nature of the chemical bonds for both molecules that has been studied [32–35] . In addition, Yar et al [36] said the laplacian of the electron density with energy density are in the range of H‐bonding.…”

Section: Resultsmentioning

confidence: 93%

“…It was also shown that, laplacian electron density for NU/POM(NO 2 ) systems had the lowest value that was the only negative recorded (À 0.0650) and with the highest electronic energy density (À 0.1284) which indicate the occurrence of shared interaction, thus implies the covalent nature of the chemical bonds for both molecules that has been studied. [32][33][34][35] In addition, Yar et al [36] said the laplacian of the electron density with energy density are in the range of H-bonding.…”

Section: Quantum Theory Of Atoms In Molecules Descriptionmentioning

confidence: 99%

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Intermolecular Interactions between Nitrosourea and Polyoxometalate compounds

et al. 2022

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Herein, the aim of this work was to investigate the intermolecular interactions between polyoxometalate (POMs) as a drug-delivery system with nitrosourea at different sites: CH 3, COOH, NH 2, NO 2 and OCH 3 using density functional theory (DFT) at the M062X/LanL2DZ level of theory. The result showed that, the lowest bond lengths recorded for the adsorbate and the nanocage were 1.40Å, 1.64Å, 1.40Å and 1.57Å for NU/ POM(CH 3 ), NU/POM(NH 2 ), NU/POM(NO 2 ) and NU/POM(OCH 3 ) respectively. The NU/POM(NO 2 ) system had the highest adsorption energy in the three phases: À 32.039, À 26.95, and À 29.38 kcal/mol for gas, solvent, and benzene respectively and the lowest was shown in NU/POM(OCH 3 ) with À 14.10, À 10.33, À 12.29 kcal/mol. The energy gap was found to be the highest in NU/POM(NO 2 ) with 5.061eV followed by NU/POM and NU/ POM(COOH) 4.020eV and 4.003eV respectively. It has been clearly shown that NU/POM(NO 2 ) density peak in the Highest occupied molecular orbital and Lowest unoccupied molecular orbital (HOMO/LUMO) plot was above 5 and this go in line with the electronic properties possessing a stable nature. In the NBO analysis, after adsorption of the nitrosourea (NU), the NU/ POM(NO 2 ) system recorded the highest energy with 1309.42 kcal/mol and the lowest in NU/POM(OCH 3 ) with 921.75 kcal/mol. The system with NO 2 possess more stability, chemical hardness, electrophilicity index and strong interactions. It has a better surface interaction than other compounds found in Nitrosourea.

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Section: Resultsmentioning

confidence: 93%

Section: Quantum Theory Of Atoms In Molecules Descriptionmentioning

confidence: 99%

Intermolecular Interactions between Nitrosourea and Polyoxometalate compounds

et al. 2022

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“…The shape of the mass spectra of pyridine oxides 1 and 2 corresponds to the shape of the mass spectra recorded during synchronous electronographic/mass spectrometric (EG/MS) studies [ 18 , 19 ], despite the fact that the vapor temperature of the studied compounds in EG/MS experiments exceeded the temperature range of our research by 20‒50°C. This allows us to conclude that pyridine oxides 1 and 2 are thermally stable over a wider temperature range.…”

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confidence: 71%

“…Our quantum-chemical study of a number of N- oxides [ 17 ] made it possible to detect the effect of donor and acceptor substituents on some characteristics of the N→O bond, whereas the electron diffraction study of 4-CH 3 PyO 1 [ 18 ] and 4-NO 2 PyO 2 [ 19 ] molecules helped to refine their structure (Fig. 1 ).…”

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confidence: 99%

Sublimation Enthalpies of Substituted Pyridine N-Oxides

et al. 2021

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“…It has been assumed that the presence of the nitro group in the substituted pyridine N-oxides is responsible for a substantial increase in the antifungal activity. 25 In this study, NPNO and p-aminobenzoic acid (PABA) were selected as the model compounds for three reasons. First, NPNO is a yellow platelike crystal and PABA is a white needlelike (α) or platelike (β) crystal, while the cocrystal of the two is bright orange, which makes it easy to determine the formation of the cocrystals during both the grinding and solution crystallization experiments.…”

Section: Introductionmentioning

confidence: 99%

Study on Thermodynamics, Crystallization Kinetics, and Molecular Simulation of Cocrystals: The Case of 4-Nitropyridine N-Oxide/p-Aminobenzoic Acid

Zhang

Yang

et al. 2022

Crystal Growth & Design

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Dry grinding and solvent-drop grinding to prepare the cocrystals of 4-nitropyridine N-oxide (NPNO) and p-aminobenzoic acid (PABA) were investigated in this study. Seven solvents were used during the solvent-drop grinding to accelerate the formation of the cocrystal, and the corresponding implicit solvent models were applied to compute the binding energy between NPNO and PABA via Gaussian 09 to determine the effect of the solvent on solvent-drop grinding. With a combination of Raman spectroscopy and powder Xray diffraction (PXRD), the ternary phase diagrams of the NPNO− PABA−acetonitrile system at different temperatures were experimentally determined. It was found that the formation of the cocrystal is mainly due to the involvement of an O•••H−O hydrogen bond between the −NO group of NPNO and the −OH group of PABA, and the stronger the binding energy of O•••H−O in solvents, the faster the formation of the cocrystal. The crystallization region of the cocrystal of NPNO and PABA becomes larger with an increase in temperature. From an analysis of Ksp and K 11 , the equationT is satisfied when the experimental temperature is 308.15 K, and a 1:1 complex solution model was used to describe the NPNO−PABA−acetonitrile system at 308.15 K. While the equation was not satisfied at 298.15 K, a solution-free complexation model was applied to describe the system at 298.15 K. The solution crystallization of the cocrystal of NPNO and PABA was successfully monitored by in situ Raman, PXRD, and a polarizing microscope, which collaboratively indicate that the nucleation of the cocrystal occurred almost immediately as soon as the two components were mixed in acetonitrile, and the dissolution processes of NPNO and PABA are the rate-determining steps during the solution crystallization of the cocrystals of NPNO and PABA.

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Molecular structure and electron distribution of 4-nitropyridine N-oxide: Experimental and theoretical study of substituent effects

Cited by 9 publications

References 44 publications

Intermolecular Interactions between Nitrosourea and Polyoxometalate compounds

Intermolecular Interactions between Nitrosourea and Polyoxometalate compounds

Sublimation Enthalpies of Substituted Pyridine N-Oxides

Study on Thermodynamics, Crystallization Kinetics, and Molecular Simulation of Cocrystals: The Case of 4-Nitropyridine N-Oxide/p-Aminobenzoic Acid

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