Das Infrarotspektrum des Nitrobenzols-15N

Dähne, S.; Stanko, Helga

doi:10.1016/s0371-1951(62)80166-0

Cited by 15 publications

(4 citation statements)

References 4 publications

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“…The negative band from the symmetric [ 15 N]nitro vibration overlaps with a positive band at 1318 cm -1 , and its true position is probably nearer to 1325 cm -1 where it appears without overlap in the spectrum recorded after 2.7 s (data not shown). The true downshift is therefore ∼22 cm -1 , consistent with the reported shift of 24 cm -1 for the ν s vibration of [ 15 N]nitrobenzene …”

Section: Resultssupporting

confidence: 87%

Time-Resolved Infrared Spectroscopy of Intermediates and Products from Photolysis of 1-(2-Nitrophenyl)ethyl Phosphates: Reaction of the 2-Nitrosoacetophenone Byproduct with Thiols

Barth¹,

Corrie²,

Gradwell³

et al. 1997

J. Am. Chem. Soc.

116

114

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Rapid scan Fourier transform infrared (FTIR) spectroscopy and time-resolved single wavelength infrared (IR) spectroscopy have been applied to study the mechanism of photochemical release of adenosine 5‘-triphosphate (ATP) from its P 3-[1-(2-nitrophenyl)ethyl] ester (caged ATP). Bands arising from phosphate and non-phosphate vibrations characteristic of the aci-nitro anion intermediate and from free ATP and byproducts of the nitrophenylethyl group have been assigned using 13C, 15N, and 18O isotopomers of caged ATP. Monitoring several of these bands using time-resolved single frequency IR spectroscopy confirms that release of ATP occurs in a single exponential process synchronous with the decay of the aci-nitro anion intermediate. Spectral characteristics of the reaction products arising from the 1-(2-nitrophenyl)ethyl group in the absence and presence of dithiothreitol (DTT) have been determined. The major final byproduct from photolysis conducted in the presence of DTT is 3-methylanthranil. The mechanism of formation of this compound from 2-nitrosoacetophenone has been investigated in detail by a combination of spectroscopic, kinetic, and chemical methods and reconciled with earlier data. The byproduct species likely to be present on the time scale of most biological experiments using caged compounds is 2-hydroxylaminoacetophenone as a mixture of ring-chain tautomers.

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Section: Resultssupporting

confidence: 87%

Time-Resolved Infrared Spectroscopy of Intermediates and Products from Photolysis of 1-(2-Nitrophenyl)ethyl Phosphates: Reaction of the 2-Nitrosoacetophenone Byproduct with Thiols

Barth¹,

Corrie²,

Gradwell³

et al. 1997

J. Am. Chem. Soc.

116

114

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“…Since the 1960s, quite different interpretations of the spectra of liquid NB and its d 5 , 15 N, 18 O 1 , 18 O 2 , 13 C 6 , andd 1 -para isotopomers [1,2,[7][8][9][10][11][12][13][14][15][16], as well as of liquid and solid sym-TNB and its d 5 isotopomer [1,2,[17][18][19], have been suggested in a number of publications. 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.…”

Section: Literature Data On Spectroscopy Studiesmentioning

confidence: 99%

“…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: 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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“…Vibrational assignments have been made for the d0, 4-dj and d5 species [93][94][95][96][97][98][99], A normal coordinate analysis using the three deuterated species along with the 1!1N and 180 species was reported by Kuwae [100], These calculated frequencies were used to deter mine the H/D fractionation factor.…”

Section: Nitrobenzenementioning

confidence: 99%

Protium -Deuterium Fractionation Factors for Organic Molecules Calculated From Vibrational Force Fields

Shiner¹,

Neumann²

1989

Zeitschrift Für Naturforschung A

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P r o tiu m -D e u te r iu m F r a c tio n a tio n F a c to r s fo r O r g a n ic M o le c u le s C a lc u la te d F ro m V ib r a tio n a l F o rc e F ie ld s Vernon J. Shiner, Jr. and Thomas E. Neumann Department of Chemistry, Indiana University, Bloomington, Indiana 47405 Z. Naturforsch. 44 a, 337-354 (1989); received February 6, 1989 This paper is dedicated to Professor Jacob Bigeleisen on the occasion of his 70th birthday New valence force fields have been calculated for forty-seven small organic molecules and used to calculate protium-deuterium fractionation factors. Factors for molecules of the type CH ,X and HCOX have been found to correlate with the electronegativities of X and the CX bond lengths. The effects of cumulative substitution on a given C atom on the alpha CH fractionation factors have been examined. Some uses of the factors in mechanistic analysis are discussed. Early applications of the Bigeleisen-Mayer theory involved the calculation of isotopic fractionation fac tors for small molecules from observed vibrational fre quencies [6] and provided useful results for sufficiently large primary isotope effects. Following the general availability of computers and the development of pro grams allowing the application of the Wilson FG ma trix method [7] to the solution of the vibrational prob lem for fairly complex molecules [8,9] it became possible to improve the accuracy of the calculations through the use of frequencies calculated from force fields which had been developed to give the best fit to observed frequencies [10].Hartshorn [11] reported the first calculation of hy drogen and carbon fractionation factors for a moderate-sized group of small organic molecules; he was able to show that these factors varied in regular and predictable ways with variations in the local structural environment at the site of isotopic substitution. Since that time the number of molecules for which appropri ately accurate spectroscopic data are available has Reprint requests to Prof. V. J. Shiner,

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Das Infrarotspektrum des Nitrobenzols-15N

Cited by 15 publications

References 4 publications

Time-Resolved Infrared Spectroscopy of Intermediates and Products from Photolysis of 1-(2-Nitrophenyl)ethyl Phosphates: Reaction of the 2-Nitrosoacetophenone Byproduct with Thiols

Time-Resolved Infrared Spectroscopy of Intermediates and Products from Photolysis of 1-(2-Nitrophenyl)ethyl Phosphates: Reaction of the 2-Nitrosoacetophenone Byproduct with Thiols

Protium -Deuterium Fractionation Factors for Organic Molecules Calculated From Vibrational Force Fields

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