Observations of Ethyl-Substituted Cyclohexanone and Cyclopentanone Rotamers Using Resonance-Enhanced Multiphoton Ionization Spectroscopy

Nesselrodt, Dale R.; Potts, Alan R.; Baer, Tomas

doi:10.1021/j100013a015

Cited by 19 publications

(15 citation statements)

References 11 publications

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“…[1][2][3][4] However, one can also use it directly as an analytical technique by measuring the ionization current with an electrode. In the REMPI process, a molecule is excited by a photon, or photons, whose energy is in resonance with an electronic state of the molecule.…”

Section: Introductionmentioning

confidence: 99%

Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc

et al. 2004

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Resonance-enhanced multiphoton ionization ͑REMPI͒ is investigated as a potential technique for realtime monitoring of selected volatile organochloride compounds ͑VOCs͒. In a proof-of-concept experiment, the progress of the reductive-degradation of tetrachloroethylene ͑PCE͒ to trichloroethylene ͑TCE͒ by zero-valent zinc was monitored by REMPI measurements performed in the headspace above the PCE solution. Two-photon resonant REMPI spectra of TCE and PCE were recorded over the wavelength range 305-320 nm. The concentrations of PCE and TCE in the headspace were monitored by measurement of the ionization signal with 315.64-and 310.48-nm excitation for PCE and TCE, respectively. Calibration curves yielded a linear range of more than 2 orders of magnitude for both compounds. The REMPI headspace results agreed well with the solution-phase results from gas chromatography analysis, which was used for independent verification of the progress of the reaction.

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Section: Introductionmentioning

confidence: 99%

Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc

et al. 2004

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“…In addition to the microwave studies, there have been some resonance-enhanced multiphoton ionization (REMPI) studies of methyl and ethyl derivatives of cyclohexanone and cyclopentanone molecules (4). The multiple conformers have been effectively frozen in a supersonic expansion and spectroscopically analyzed by 2 ϩ 1 REMPI via the 3s 4 n Rydberg transition.…”

Section: Introductionmentioning

confidence: 99%

“…For 2-methylcyclohexanone, the REMPI spectrum differed significantly and the interaction between the methyl and carbonyl groups caused a geometry change on excitation of a low-lying vibration in the 3s Rydberg state. The REMPI spectra of the ethyl-substituted cyclohexanones were also observed and analyzed unambiguously with the aid of the ab initio MO methods (4).…”

Section: Introductionmentioning

confidence: 99%

Microwave Spectrum of 2-Methylcyclohexanone

Lee

2000

Journal of Molecular Spectroscopy

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“…7,8 The resonance enhanced multiphoton ionization (REMPI) method has been applied to methyl-and ethyl-derivatives of cyclohexanone to investigate the various conformers as well as cyclic ketone and cyclic ether including oxygen. [9][10][11] The structural information was compared with ab initio density functional theory to calculate not only the structure of cyclohexanone, but the vibrational spectra of isotopomers of cyclohexanone as well. The information was compared with electron diffraction structure and liquid-phase IR spectra.…”

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confidence: 99%

Dipole Moments of Methyl - Substituted Cyclohexanone

Ka¹,

Kim²,

2011

Bulletin of the Korean Chemical Society

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The structure of cyclohexanone from electron diffraction study and microwave spectrum has been reported previously. [1][2][3] The dipole moment of cyclohexanone was measured to be 2.87 (4) Debye from the Stark displacements of a few microwave transitions.2 The geometry of cyclohexanone was further improved by least-squares analysis of both by the gas-phase electron diffraction and microwave data. 3 The heavy atom structural parameters for the chair form of its ground state are reported. 4The Microwave spectra of 4-thiacyclochexanone in the ground state and eight vibrationally excited states have also been studied and the data are consistent with a chair conformation for the ring. 5The microwave spectrum of 3-methylcyclopentanone has been studied and the dipole components μa = 2.97(2), μb = 1.00(3), μ c = 0.18(5), and μ tot = 3.14(3) D were reported. 6These were consistent with a twisted-ring conformation with a methyl group in the equatorial position. The conformation of 3-, 4-methyl cyclohexanone in its ground state has been reported to be a chair form with the methyl group in the equatorial position. 7,8 The resonance enhanced multiphoton ionization (REMPI) method has been applied to methyl-and ethyl-derivatives of cyclohexanone to investigate the various conformers as well as cyclic ketone and cyclic ether including oxygen.9-11 The structural information was compared with ab initio density functional theory to calculate not only the structure of cyclohexanone, but the vibrational spectra of isotopomers of cyclohexanone as well. The information was compared with electron diffraction structure and liquid-phase IR spectra. 12The dominant conformations of methyl cyclohexanone and their interconversion rate at room temperature in which the methyl group is either axial or equatorial to the six membered rings have been also reported as well as the interconversion rate of ethyl rotor of ethylcyclohexanone. 13While the dipole moments of 3-and 4-methylcyclohexanones are reported previously, the dipole moment of 2-methylcyclohexanone has not been reported. [14][15][16] In this paper, the dipole moment of 2-methylcyclohexanone has been measured using the second-order Stark effects in the microwave region.Since all the experimental dipole moments for the methylsubstituted cyclohexanones are reported, these are compared with those calculated using Gaussian03. 17 The geometric parameters of each molecule were calculated by applying the Møl-ler-Plesset (MP2) perturbation theory, 6-311++G(2d,2p) basis set.The induced dipole moments of the methyl, ethyl cyclohexanone are calculated on the assumption that the dipole moment is located mostly at the C=O bond and the values of induced dipole moments are relatively in good agreement with the ab initio results. ExperimentalThe rotational spectrum of 2-methylcyclohexanone was measured by using Fourier Transform Microwave Spectrometer (FTMS) with a pulsed gas nozzle described previously. 18-20The sample was purchased from Aldrich Chemical Company. About 1 -2 atm of Ar gas was bubbled ...

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Observations of Ethyl-Substituted Cyclohexanone and Cyclopentanone Rotamers Using Resonance-Enhanced Multiphoton Ionization Spectroscopy

Cited by 19 publications

References 11 publications

Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc

Resonance-enhanced multiphoton ionization for real-time monitoring of trichloroethylene formed by degradation of tetrachloroethylene using zero-valent zinc

Microwave Spectrum of 2-Methylcyclohexanone

Dipole Moments of Methyl - Substituted Cyclohexanone

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