Microwave Spectra, Dipole Moments, and Torsional Potential Constants of <i>cis</i>- and <i>trans</i>-Cyclopropanecarboxylic Acid Fluoride

Volltrauer, H.; Schwendeman, R. H.

doi:10.1063/1.1674603

Cited by 50 publications

(4 citation statements)

References 9 publications

(1 reference statement)

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“…Conformational properties of substituted cyclopropanes have interested chemists for a long time. It has been shown that the preferred forms of cyclopropane derivatives, which contain substituents with unsaturated groups such as CHO, 1 CFO, 2 CClO, 3 COOH, 4 CHdCH 2 , 5 and NO 2 , 6 have a symmetry plane (C s symmetry), with the substituent lying in this plane. A different conformational preference is observed for cyclopropanols.…”

Section: Introductionmentioning

confidence: 99%

A Microwave and Quantum Chemical Study of Cyclopropanethiol

Møllendal¹,

Guillemin

2008

J. Phys. Chem. A

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The microwave spectra of cyclopropanethiol, C(3)H(5)SH, and one deuterated species C(3)H(5)SD, have been investigated in the 20 - 80 GHz frequency range. The spectra of the ground vibrational state and of three vibrationally excited states of the parent species of a conformer which has a synclinal ("gauche") arrangement for the H-C-S-H chain of atoms, was assigned. The H-C-S-H dihedral angle is 76(5)° from synperiplanar (0°). The b-type transitions of the ground and of the vibrationally excited states of the parent species were split into two components, which is assumed to arise from tunneling of the proton of the thiol group between two equivalent synclinal potential wells. No splitting was resolved in the spectrum of C(3)H(5)SD. The tunneling frequency of the ground vibrational state of C(3)H(5)SH is 1.664(22) MHz. The tunneling frequency of the first excited-state of the C-S torsion is 52.330(44) MHz, whereas this frequency is 26.43(13) and 3.286(61) MHz, respectively, for the first excited states of the two lowest bending vibrations. The dipole moment of the ground vibrational state of the parent species is μ(a) = 4.09(5), μ(b) = 2.83(11), μ(c) = 0.89(32), and μ(tot) = 5.06(16) × 10(-30) C m. The microwave study has been augmented by high-level density functional and ab initio quantum chemical calculations.

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Section: Introductionmentioning

confidence: 99%

A Microwave and Quantum Chemical Study of Cyclopropanethiol

Møllendal¹,

Guillemin

2008

J. Phys. Chem. A

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“…However, the presence of this ring is a complicating factor that is likely to have interesting conformational consequences. In cyclopropane derivatives with unsaturated substituents such as CHO, CFO, CClO, CO 2 H, vinyl, or nitro, the most stable conformations are those with the plane of the substituent in the symmetry plane of the molecule. CC−C−O syn form(s) are thus expected for ECP when this compound is regarded as a cyclopropyl derivative with an unsaturated substituent.…”

Section: Introductionmentioning

confidence: 99%

Microwave Spectrum, Conformational Equilibrium, Intramolecular Hydrogen Bonding, Tunneling, and Quantum Chemical Calculations for 1-Ethenylcyclopropan-1-ol

et al. 2000

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The microwave spectra of 1-ethenylcyclopropan-1-ol, (CH 2 ) 2 C(OH)CdCH 2 , and one deuterated species, (CH 2 ) 2 C(OD)CdCH 2 , have been investigated in the 11.0-60.0 GHz region. The (ac,ap)-and (ac,sc1)-conformers denoted Syn 1 and Skew 1 were assigned. Each of these two forms is stabilized with an intramolecular hydrogen bond formed between the hydrogen atom of the hydroxyl group and the π electrons of the double bond. In the Syn 1 rotamer the CdC-C-O chain of atoms takes a syn conformation (dihedral angle ) -2.6°) and the H-O-C-Cd link of atoms is gauche (dihedral angle ) -67.2°from syn). The CdC-C-O link of atoms takes a skew conformation (dihedral angle ) 132.1°from syn) in the Skew 1 rotamer, while the H-O-C-C) dihedral angle is -67.1°. Syn 1 is preferred by 4.9(6) kJ mol -1 relative to Skew 1. Syn 1 is virtually a hybrid of the most stable conformer of unsubstituted ethenylcyclopropane, and unsubstituted cyclopropanol, Skew 1, is the corresponding hybrid of the second rotamer of ethenylcyclopropane and the most stable one of cyclopropanol. The spectrum of Syn 1 is perturbed by tunneling of the hydroxyl group. An analysis yielded 2280.184(60) MHz for the tunneling frequency and 39.82(19) MHz for the Coriolis coupling term µ ca for the normal species. The corresponding values were 72.401(27) and 5.2(10) MHz, respectively, for the deuterated species. A potential function for the tunneling motion consisting of three cosine terms was found to have the following potential constants: V 1 ) -918.2, V 2 ) -900.0, and V 3 ) 418.0 cm -1 . This double-minimum function yields a barrier of 16.6(50) kJ mol -1 at the anti position and 10.6(30) kJ mol -1 at syn. The microwave work has been assisted by ab initio computations at the MP2/ccpVTZ level of theory as well as density functional theory calculations at the B3LYP/6-31G* level. These calculations indicate that there are only three stable rotameric forms of the molecule. The gas-phase IR spectrum in the O-H stretching region revealed a broad and complex band red-shifted by roughly 50 cm -1 presumably as a result of internal hydrogen bonding.

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“…Finally, the three cyclopropylcarbonyl halides (X = F, Cl, Br) consist of predominately cis conformers with less stable trans conformers also present in the fluid states. 7,8 On the other hand, however, the trans conformer has been determined to be more stable for the cyclopropylsubstituted ethenes that have been studied. Vinylcyclopropane has been the subject of a number of exhaustive studies,5,9 but the latest study by Carreira et al appears to be the most definitive.…”

Section: Introductionmentioning

confidence: 99%

Vibrational spectra and structure of dicyclopropyl ketone and 1,1-dicyclopropylethene

Nease¹,

Wurrey²

1979

J. Phys. Chem.

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The infrared spectra of dicyclopropyl ketone and 1,1-dicyclopropylethene have been measured from 4000 to 200 cm'1 in the liquid and vapor phases. Additionally, Raman spectra of the liquid and polycrystalline solid phases of both compounds have also been recorded. Complete vibrational assignments have been proposed for both molecules. The spectra of both compounds are consistent with the cis-cis conformer of each compound (with C2l) molecular symmetry). Moreover, no indication of the presence of any other conformer was observed in the spectra of either compound.

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Microwave Spectra, Dipole Moments, and Torsional Potential Constants of cis- and trans-Cyclopropanecarboxylic Acid Fluoride

Cited by 50 publications

References 9 publications

A Microwave and Quantum Chemical Study of Cyclopropanethiol

A Microwave and Quantum Chemical Study of Cyclopropanethiol

Microwave Spectrum, Conformational Equilibrium, Intramolecular Hydrogen Bonding, Tunneling, and Quantum Chemical Calculations for 1-Ethenylcyclopropan-1-ol

Vibrational spectra and structure of dicyclopropyl ketone and 1,1-dicyclopropylethene

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