The microwave spectrum and conformation of cyclobutanol

Macdonald, John N.; Norbury, D.; Sheridan, J.

doi:10.1016/0584-8539(78)80035-x

Cited by 15 publications

(15 citation statements)

References 20 publications

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“…The parameters from this study were used to predict the rotational constants for the corresponding alcohol [11]. Electron diffraction studies [12] have been used to obtain average values for the C-C and C-Cl distances for both conformers of chlorocyclobutane but small differences in bond length between the conformers could not be determined but the two different puckering angles were reported.…”

Section: Introductionmentioning

confidence: 99%

The r 0 structural parameters of equatorial and axial chlorocyclobutane, conformational stability from temperature dependent infrared spectra of xenon solutions, and vibrational assignments

et al. 2008

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Variable temperature (-55 to -100°C) studies of the infrared spectra (4,000-400 cm -1 ) of chlorocyclobutane, c-C 4 H 7 Cl, dissolved in liquid xenon have been carried out. The infrared spectrum (4,000-100 cm -1 ) of the gas has also been recorded. For this puckered ring molecule the enthalpy difference between the more stable equatorial conformer and the axial form, has been determined to be 361 ± 17 cm -1 (4.32 ± 0.20 kJ/mol). This stability order is consistent with that predicted by ab initio calculations but the DH is much lower than the average energy value of 646 ± 73 cm -1 obtained from the MP2 ab initio calculations or 611 ± 28 cm -1 from the B3LYP density functional theory calculations. The percentage of the axial conformer present at ambient temperature is estimated to be 15 ± 1%. By utilizing previously reported microwave rotational constants for both conformers combined with ab initio MP2(full)/6-311?G(d,p) predicted structural values, adjusted r 0 parameters have been obtained. The determined heavy atom structural parameters for the equatorial conformer are: the distances C-Cl = 1.783(5), C 1 -C 4 = 1.539(3), C 4 -C 6 = 1.558(3) Å , and angles \C 6 C 4 C 1 = 86.9(5), \C 4 C 1 C 5 = 89.7(5)°, and for the axial conformer are: the distances C-Cl = 1.803(5), C 1 -C 4 = 1.547(3), C 4 -C 6 = 1.557(3) Å , and angles \C 6 C 4 C 1 = 86.3(5), \C 4 C 1 C 5 = 88.9(5) and the puckering angles for the equatorial and axial conformers are 30.7(5)°and 22.3(5)°, respectively. The conformational stabilities, harmonic force fields, infrared intensities, Raman activities, depolarization ratios and vibrational frequencies have been obtained for both conformers from MP2(full)/6-31G(d) ab initio calculations and compared to experimental values where available. The results are discussed and compared to the corresponding properties of some similar molecules.

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Section: Introductionmentioning

confidence: 99%

The r 0 structural parameters of equatorial and axial chlorocyclobutane, conformational stability from temperature dependent infrared spectra of xenon solutions, and vibrational assignments

et al. 2008

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“…1), the rotational constants from the parent species were utilized. Rotational spectra of the parent and OD isotopomers were reported by Macdonald et al [9]. We first improve the fit of the normal species (all 12 C atoms) by remeasuring the reported transitions more precisely due to the high resolution of FTMW spectrometer and measuring some new transitions.…”

Section: Resultsmentioning

confidence: 96%

“…From more recent microwave investigations of the fluoride [7] and chloride [8] the axial forms have been identified so the substitution of a group with an asymmetric rotor such as OH, SH, NH 2 , PH 2 , etc., could lead to the presence of four conformers. However, in both the previous microwave investigations of the cyclobutanol [9] and the cyclobutylamine [10,11], only one conformer was identified. For the cyclobutanol the spectrum of the equatorial-trans form was predicted from the previously reported parameters for the cyclobutyl chloride [5] and methanol [12].…”

Section: Introductionmentioning

confidence: 83%

“…For the cyclobutanol the spectrum of the equatorial-trans form was predicted from the previously reported parameters for the cyclobutyl chloride [5] and methanol [12]. Since only the normal and O-D isotopomers were investigated [9] very little structural information was obtained in this initial microwave investigation of cyclobutanol. In fact, there is limited structural information on the monosubstituted cyclobutanes which could be part of the reason why the second or even the third conformers of monosubtituted cyclobutanes containing an asymmetric rotor have not be identified in the microwave spectra.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Durig [15] et al . studied the temperature dependent infrared spectra of cyclobutanol in xenon solutions and carried out ab initio calculations combined with the previously reported [9] rotational constants to obtained the r 0 structural parameters.…”

Section: Introductionmentioning

confidence: 99%

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