Crystal structure of 4-methylpyridine N-oxide, C6H7NO

Morris, E. Kaiser; Cousson, A.; Paulus, W.

doi:10.1524/ncrs.1998.213.14.80

Cited by 3 publications

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“…Table 4 compares the structure of pyridine-N-oxide and its two substituted obtained by GED, X-ray and DFT. Taking into account that the structural parameters obtained by different methods have different physical meaning, we can note a good agreement of the values obtained in our research (therein and [24]) with the theoretical results (therein and [21]) and, also, with the parameters for the crystals [46,47] in contrast to the values recommended by Chiang J. F. et al [20]. Apparently, some increase of the semipolar N/O bond lengths in a crystal phase compared to the free molecules is due to intermolecular hydrogen bonding.…”

Section: Resultssupporting

confidence: 86%

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

Belova

Pimenov

Kotova

et al. 2020

Journal of Molecular Structure

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The molecular structure of 4-nitropyridine N-oxide, 4-NO 2 -PyO, has been determined by gas-phase electron diffraction monitored by mass spectrometry (GED/MS) and by quantum chemical calculations (DFT and MP2). Comparison of these results with those for non-substituted pyridine N-oxide and 4methylpyridine N-oxide CH 3 -PyO, demonstrate strong substitution effects on structural parameters and electron density distribution. The presence of the electron-withdrawing eNO 2 group in para-position of 4-NO 2 -PyO results in an increase of the ipso-angle and a decrease of the semipolar bond length r(N/O) in comparison to the non-substituted PyO. The presence of the electron-donating eCH 3 group in 4-CH 3 -PyO leads to opposite structural changes. Electron density distribution in pyridine-N-oxide and its two substituted compounds are discussed in terms of natural bond orbitals (NBO) and quantum theory atoms in molecule (QTAIM).

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Section: Resultssupporting

confidence: 86%

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

Belova

Pimenov

Kotova

et al. 2020

Journal of Molecular Structure

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“…Crystal of oxide 1 consists of two types of structural units, in which two molecules are oriented to each other by СН 3 (H∙∙∙H 3.1 Å) or N→O (O∙∙∙O 4.7 Å) groups. The pyridine fragments in these units are located in mutually perpendicular planes [ 27 ]. Such a crystalline packing is not dense, and this facilitates the sublimation of compound 1 .…”

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Sublimation Enthalpies of Substituted Pyridine N-Oxides

et al. 2021

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The molecular structure of 4-methylpyridine-N-oxide: Gas-phase electron diffraction and quantum chemical calculations

Belova

Girichev

Kotova

et al. 2018

Journal of Molecular Structure

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a b s t r a c tThe molecular structure of 4-methylpiridine-N-oxide, 4-MePyO, has been studied by gas-phase electron diffraction monitored by mass spectrometry (GED/MS) and quantum chemical (DFT) calculations. Both, quantum chemistry and GED analyses resulted in C S molecular symmetry with the planar pyridine ring. Obtained molecular parameters confirm the hyperconjugation in the pyridine ring and the sp 2 hybridization concept of the nitrogen and carbon atoms in the ring. The experimental geometric parameters are in a good agreement with the parameters for non-substituted N-oxide and reproduced very closely by DFT calculations. The presence of the electron-donating CH 3 substituent in 4-MePyO leads to a decrease of the ipso-angle and to an increase of r(N/O) in comparison with the non-substituted PyO. Electron density distribution analysis has been performed in terms of natural bond orbitals (NBO) scheme. The nature of the semipolar N/O bond is discussed.

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Crystal structure of 4-methylpyridine N-oxide, C6H7NO

Cited by 3 publications

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

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

Sublimation Enthalpies of Substituted Pyridine N-Oxides

The molecular structure of 4-methylpyridine-N-oxide: Gas-phase electron diffraction and quantum chemical calculations

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