Microwave spectrum and planarity of nitrobenzene

Høg, Jens H.; Nygaard, Lise; Sørensen, Georg

doi:10.1016/0022-2860(71)90012-3

Cited by 104 publications

(25 citation statements)

References 15 publications

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“…This result is exactly the same (both for its magnitude and its estimated error) as obtained using the static model in Ref. 4 and is also in good agreement with the experimental MW value (3.0 ± 1.5 kcal/mol) [1] and the result of theoretical G3X method (4.7 kcal/mol), which gives reasonable predictions of energies. Furthermore, the present results are in excellent agreement with the value of 4.5 kcal/mol determined from the dynamic model by Monte Carlo optimization [5].…”

Section: Resultssupporting

confidence: 87%

“…2). For this theoretical model, the barrier height to orthogonal conformation (3.5 kcal/mol) is very close to the experimental value of 3.0±1.5 kcal/mol determined from MW study [1]. The values of the barrier, 4.7 and 4.8 kcal/mol, predicted by G3X and MP2/augcc-pVTZ methods, respectively, are consistent with the experimental one if considering the inherent uncertainties of the techniques involved.…”

Section: Geometry and Torsional Potentialsupporting

confidence: 85%

“…Due to this, the static model was used in the joint analysis of GED and MW data. The rotational constants A 0 , B 0 , and C 0 determined by MW spectroscopy [1] were corrected to A e , B e , and C e values using corrections (B e (i) -B 0 (i) ) calculated from the B3LYP/cc-pVTZ quadratic and cubic force constants as described above. The values of corrections and corrected experimental rotational constants are given in Table 10 together with the rotational constants calculated from the r e structure by combined analysis of GED and MW data.…”

Section: Combined Analysis Of Ged Data and Rotational Constantsmentioning

confidence: 99%

“…Of particular value is the reanalysis of the experimental MW spectra [1,2] carried out in this work using the method for determination of the equilibrium geometry of a molecule from experimental rotational constants and theoretical rotational-vibrational interaction constants [9].…”

Section: Introductionmentioning

confidence: 99%

“…Although the molecular structure of gaseous nitrobenzene was investigated by microwave spectroscopy (MW) [1,2], gas-phase electron diffraction (GED) [3][4][5], IR and Raman spectroscopy (see Refs. [6,7] and references within), we found it desirable to acquire more accurate data on the structure of this important molecule, especially concerning its form of torsion and the values of its bond length C-N and angle \CC NO 2 C: According to MW spectra, the nitrobenzene has the planar structure of C 2v symmetry.…”

Section: Introductionmentioning

confidence: 99%

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Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction, rotational constants, and theoretical calculations

et al. 2007

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The molecular structure and conformation of nitrobenzene has been reinvestigated by gas-phase electron diffraction (GED), combined analysis of GED and microwave (MW) spectroscopic data, and quantum chemical calculations. The equilibrium r e structure of nitrobenzene was determined by a joint analysis of the GED data and rotational constants taken from the literature. The necessary anharmonic vibrational corrections to the internuclear distances (r e -r a ) and to rotational constants (B e (i) -B 0 (i) ) were calculated from the B3LYP/ccpVTZ quadratic and cubic force fields. A combined analysis of GED and MW data led to following structural parameters (r e ) of planar nitrobenzene (the total estimated uncertainties are in parentheses): r(C-C) av = 1.391 (3) Å , r(C-N) = 1.468(4) Å , r(N-O) = 1.223(2) Å , r(C-H) av = 1.071(3) Å , \C2-C1-C6 = 123.5(6)°, \C1-C2-C3 = 117.8(3)°, \C2-C3-C4 = 120.3(3)°, \C3-C4-C5 = 120.5(6)°, \C-C-N = 118.2(3)°, \C-N-O = 117.9(2)°, \O-N-O = 124.2(4)°, \(C-C-H) av = 120.6(20)°. These structural parameters reproduce the experimental B 0 (i) values within 0.05 MHz. The experimental results are in good agreement with the theoretical calculations.The barrier height to internal rotation of nitro group, 4.1±1.0 kcal/mol, was estimated from the GED analysis using a dynamic model. The equilibrium structure was also calculated using the experimental rotational constants for nitrobenzene isotopomers and theoretical rotation-vibration interaction constants.

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Section: Resultssupporting

confidence: 87%

Section: Geometry and Torsional Potentialsupporting

confidence: 85%

Section: Combined Analysis Of Ged Data and Rotational Constantsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction, rotational constants, and theoretical calculations

et al. 2007

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Fundamentals of Rotational Spectroscopy

Bauder

2011

Handbook of High‐resolution Spectroscopy

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Essential features of rotational spectra are developed on the basis of the quantum mechanics of molecular rotation. The effects of the harmonic vibrations of the nuclei are considered on the molecular rotation. Permanent electric dipole moments are required for the observation of pure rotational transitions. The Stark effect is used to determine the electric dipole moment. Nuclear quadrupole splittings give information on the electronic charge distribution in molecules. Large‐amplitude internal motions in molecules lead to splittings of rotational transitions. The splittings determine the potential barriers of the internal motions.

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Nitrogen Quadrupole Coupling Constants of Nitrobenzene and o‐Nitrophenol

Heineking

Dreizler

1993

Ber Bunsenges Phys Chem

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The microwave spectra of nitrobenzene, C6H5NO2, and o‐nitrophenol, C6H4 (OH)NO2, have been observed with high resolution using a waveguide microwave Fourier transform spectrometer. Nuclear quadrupole hyperfine structures have been resolved and analysed to obtain the following nitrogen quadrupole coupling constants: χaa = ‐1.1589 (24) MHz, χbb = 0.3195 (36) MHz, χcc = 0.8394 (36) MHz for nitrobenzene; χaa = ‐1.234 (4) MHz, χbb = 0.348 (3) MHz, χcc = 0.886 (3) MHz for o‐nitrophenol. For nitrobenzene, the variation of the coupling constants with torsional state has also been studied.

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Microwave spectrum and planarity of nitrobenzene

Cited by 104 publications

References 15 publications

Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction, rotational constants, and theoretical calculations

Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction, rotational constants, and theoretical calculations

Fundamentals of Rotational Spectroscopy

Nitrogen Quadrupole Coupling Constants of Nitrobenzene and o‐Nitrophenol

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