Some characteristic vibration patterns of the organic nitro group

Varsányi, G.; Holly, S.; Imre, L.

doi:10.1016/0584-8539(67)80336-2

Cited by 28 publications

(11 citation statements)

References 6 publications

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“…The first substrate used was nitrobenzene (Figure a). After desorption of physisorbed nitrobenzene under a flow of N 2 , two peaks remain at 1526 cm –1 for the asymmetric ν as (NO 2 ) and 1349 cm –1 for the symmetric ν s (NO 2 ) mode. , The peak positions are downshifted from the ν as (NO 2 ) and ν s (NO 2 ) in gaseous nitrobenzene at 1548 and 1360 cm –1 , respectively . The downshift in the peak positions is attributed to surface adsorption.…”

Section: Resultsmentioning

confidence: 91%

“…6,52 The peak positions are downshifted from the ν as (NO 2 ) and ν s (NO 2 ) in gaseous nitrobenzene at 1548 and 1360 cm −1 respectively. 53 The downshift in the peak positions is attributed to surface adsorption. During saturation, a feature was observed at 1448 cm −1 , which is an indication of the 19a type aromatic ring vibration, but this feature disappeared after N 2 purging.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

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Revealing the Hydrogenation Performance of RuMo Phosphide for Chemoselective Reduction of Functionalized Aromatic Hydrocarbons

Bonita

O’Connell

Miller

et al. 2019

Ind. Eng. Chem. Res.

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Bimetallic transition metal phosphide catalysts are promising materials for low-temperature, liquid-phase hydrogenation reactions. This work explores the chemoselective hydrogenation ability of RuMoP using various functionalized aromatic hydrocarbons to provide insight into how the functional groups compete for reduction on the surface of RuMoP. Using molecular hydrogen as the reductant, high selectivity (∼99%) to reduction of the substituent is achieved for the hydrogenation of electron withdrawing functionalities such as nitrobenzene, benzaldehyde, and benzophenone with RuMoP to yield aniline, benzyl alcohol, and diphenylmethanol, respectively. In contrast, aromatics with electron donating groups such as phenol, anisole, and toluene, show high ring hydrogenation selectivity (∼99%) to form cyclohexanol, methoxycyclohexane, and methyl cyclohexane, respectively, although the reaction proceeded slowly with RuMoP. Pyridine adsorption was studied via diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), which provided evidence of surface electron deficient sites (i.e., Lewis acids) that are responsible for targeting the electron-rich portion of the substrate. Additional DRIFTS experiments were performed using nitrobenzene, anisole, and a mixture of the two. From these experiments, features associated with −NO2 adsorption in nitrobenzene and ring adsorption in anisole were observed, which correlated well with the observed reaction results. Finally, a solvent study provided evidence for the competitive adsorption of isopropanol and the π-electrons from the aromatic ring of phenol with the former being more favorable on RuMoP surface.

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Section: Resultsmentioning

confidence: 91%

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Revealing the Hydrogenation Performance of RuMo Phosphide for Chemoselective Reduction of Functionalized Aromatic Hydrocarbons

Bonita

O’Connell

Miller

et al. 2019

Ind. Eng. Chem. Res.

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“…Thus, taking into account degeneracy of vibrations, the Raman spectrum must contain 22 fundamentals, only six of which, belonging to species A 1 0 , are polarized. In order to provide satisfactory agreement between the theoretical frequencies and those in the newly recorded experimental spectra along with the spectra published in literature for NB, sym-TNB, and their isotopomers [1,2,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and compensate for systematic errors in directly calculated harmonic (and anharmonic) force fields, we have solved the inverse spectral problems by refining a few empirical scale factors for the force constants corresponding to various types of independent local symmetry internal coordinates in their nonredundant set (Table 5). Assignment of the experimental frequencies to various symmetry species, apart from good accordance with the calculated (Tables 6, 7 , 8, 9, 10), as well as with the NB and its 15 N modification vapor-phase IR band contours.…”

Section: Experimental Vibrational Spectra and Their Interpretation Usmentioning

confidence: 92%

“…However, these studies were unable to solve the assignment problem completely, which leads us to the conclusion that the problem cannot be solved within the framework of the vibrational spectroscopic method alone. As far as the experimental spectra in the gas phase are concerned, only 3-5 bands of the NO 2 group vibrations in the IR spectrum of the NB molecule were successfully recorded [20,21]. In this work, the IR spectra of gaseous NB and its 15 N isotopomer have been obtained in the frequency range of 3500-250 cm -1 , and the far-IR spectra of solutions of the same compounds in kerosene, benzene, and CCl 4 as well as of the NB neat liquid sample have been recorded in the range of 600-30 cm -1 .…”

Section: Literature Data On Spectroscopy Studiesmentioning

confidence: 99%

IR spectra of nitrobenzene and nitrobenzene-15N in the gas phase, ab initio analysis of vibrational spectra and reliable force fields of nitrobenzene and 1,3,5-trinitrobenzene. Investigation of equilibrium geometry and internal rotation in these simplest aromatic nitro compounds with one and three rotors by means of electron diffraction, spectroscopic, and quantum chemistry data

et al. 2015

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The IR spectra of gaseous nitrobenzene (NB) and its 15 N isotopomer have been obtained in the frequency range of 3500-250 cm -1 , and the far-IR spectra of their solutions and the NB neat liquid sample have been recorded in the range of 600-30 cm -1 . A detailed description of the spectra of NB and 1,3,5-trinitrobenzene (sym-TNB) and their isotopomers has been accomplished using the force fields calculated at the MP2(full)/aug-cc-pVTZ and MP2(full)/cc-pVTZ levels. Transferability of the refined scale factors for the calculated force constants obtained by the Pulay technique has been used to provide evidence for validity of both interpreting the NB and sym-TNB spectra and refining the calculated force fields. The direct and inverse spectral problems have been solved by variational technique to determine torsional energy levels and refine the potential function by optimizing the V k coefficients in its Fourier series expansion. The height of the MP2(full) barrier to internal rotation has been reduced from 5.5 to 4.5 kcal/mol due to extension of the used basis set from 6-31(d,p) to aug-cc-pVTZ. The method of joint dynamic structural analysis of the GED, MW, and vibrational spectroscopy, and ab initio data in terms of the PES parameters have been applied to investigation of equilibrium geometry and internal rotation in the nonrigid NB and sym-TNB molecules having one and three coupled internal rotors, respectively. The experimental r e -parameter values of both molecules (C 2v and D 3h point group symmetries) are in agreement with those obtained by ab initio calculations. This paper is dedicated to Professor Magdolna Hargittai on the occasion of her 70th birthday.

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“…In our spectra, both the symmetric and, to a lesser extent, the antisymmetric bands showed weak satellites. These must be due to rotational gauche-trans isomerism as explained before (17). The same feature accounts for the widely separated doublets of the various CH, deformation bands; most noticeably in the twisting and rocking bands.…”

Section: Liquid Spectramentioning

confidence: 81%

Infrared Studies on Rotational Isomerism. V. 2-Nitroethanol

Giguère¹,

Kawamura²

1971

Can. J. Chem.

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The i.r. spectra of 2-nitroethanol in the three physical states were measured between 4000 and 250 cm-'. The liquid and the crystal werealso studied in Raman effect. In all three states the molecules exist as gauche and trans isomers, the former being stabilized by a weak intramolecular hydrogen bond. Definite evidence for a third isomer, previously reported in dilute CCl, solutions, could not be ascertained from the vapor spectra as a function of temperature. On the other hand this study revealed appreciable decomposition of the vapor above 80 "C, with formation of nitroethylene and also some aldehyde. For that reason it was not possible to evaluate the enthalpy of isomerization. The difficulty of securing a pure sample of 2-nitroethanol is emphasized. Only one crystalline phase was obtained.On a Btudik en i.r. entre 4000 et 250 cm-l le nitro-2 ethanol sous les trois Ctats physiques. En outre on a etudie en Raman le liquide et le cristal. Dans les trois etats les ~nolecules existent sous forme d'isomeres trans et gauche. Ce dernier est stabilise par une faible liaison hydrogene interne. La presence d'un troisieme isomere, prksumement gauche, signalee dans les solutions dilutes en solvant inerte, n'a pu Ctre confirmke par une etude de la vapeur en fonction de la temperature. Celle-ci, par contre, a revel6 une decomposition appreciable a partir de 80 "C avec formation de nitrokthylene et d'un peu d'aldkhyde. Pour cette raison il n'a pas kt6 possible d'evaluer l'enthalpie d'isomkrisation gauche-trans. On souligne la difficulte de preparer un kchantillon pur de ce nitroalcool. Une seule phase cristalline a kt6 obtenue.

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Some characteristic vibration patterns of the organic nitro group

Cited by 28 publications

References 6 publications

Revealing the Hydrogenation Performance of RuMo Phosphide for Chemoselective Reduction of Functionalized Aromatic Hydrocarbons

Revealing the Hydrogenation Performance of RuMo Phosphide for Chemoselective Reduction of Functionalized Aromatic Hydrocarbons

Infrared Studies on Rotational Isomerism. V. 2-Nitroethanol

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