Semiempirical calculations of internal barriers to rotation and ring puckering

Combs, Leon L.; Rossie, Michael

doi:10.1016/0022-2860(76)80040-3

Cited by 24 publications

(5 citation statements)

References 13 publications

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“…A few electronic structure theory and spectroscopic studies focusing on the equilibrium properties such as geometry, ring puckering vibration, and nonbonded interactions have been reported in the literature. Semiempirical and ab initio , calculations indicated a planar geometry with C 2 v symmetry for this molecule (see Figure ), which is consistent with infrared , and microwave spectroscopic predictions. Synchrotron-based high-resolution infrared investigations characterizing the ground state vibrational bands of 3-oxetanone molecule have been reported recently. , …”

Section: Introductionsupporting

confidence: 80%

Dissociation Chemistry of 3-Oxetanone in the Gas Phase

2017

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3-Oxetanone is a strained cyclic molecule which plays an important role in synthetic chemistry. A few studies exist in the literature about the equilibrium properties of this molecule and the dissociation patterns of substituted 3-oxetanones. For the unsubstituted 3-oxetanone, formation of ketene (CHCO) and formaldehyde (HCHO) was considered to be the major dissociation pathway. In a recent work, pyrolysis products of 3-oxetanone molecule in the gas phase were investigated by Fourier transform infrared spectroscopy and photoionization mass spectrometry. In this study, an additional dissociation channel forming ethylene oxide (c-CHO) and carbon monoxide CO was reported. In the present work, gas phase dissociation chemistry of 3-oxetanone was investigated by electronic structure theory, ab initio classical chemical dynamics simulations, and Rice-Ramsperger-Kassel-Marcus (RRKM) rate constant calculations. The barrier height for the ethylene oxide channel was found to be much higher than the ketene pathway. The dynamics simulations were performed at three different total energies, viz., 150, 200, and 300 kcal/mol, and multiple reaction pathways and varying branching ratios observed. A new dissociation channel involving a ring-opened isomer of ethylene oxide was identified in the simulations. This pathway has a lower energy barrier and was dominant in our dynamics simulations.

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Section: Introductionsupporting

confidence: 80%

Dissociation Chemistry of 3-Oxetanone in the Gas Phase

2017

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“…Bond angles in some molecules are significantly overestimated [45], conformational equilibria should be viewed with caution where rotation occurs about an essential single bond which connects two 7r-electronic systems [46], and ring puckering in strained-ring compounds is underestimated [47]. The method successfully accounts for conformational trends in p-substituted anilines [48] and benzyl halides [49,50].…”

Section: B Geometry and Conformationmentioning

confidence: 95%

Evaluation of MINDO/3 calculations in simple amides, ureas, and heterocycles of biological interest

Defina

Andrews

1980

Int J of Quantum Chemistry

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AbstractsThe performance of the M I N D 0 / 3 method has been evaluated in simple heteroatomic molecules that are representative of several important biological systems. Molecular geometries are accurate to within 0.04 A for bond lengths, and 3" for most bond angles. Dipole moments and charge distributions are estimated satisfactorily, and ionization potentials are predicted to an accuracy of 0.5 eV. The method is less accurate in estimating the ionization of some upper level u orbitals. The overall evaluation shows that MIND0/3 provides a good description of the geometries and electronic properties of the molecules studied

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“…The structure and electronic properties of the parent unsubstituted oxetan-3-one 181 have been studied extensively by a wide range of different techniques. − Photoelectron spectroscopy was used to determine the electronic structure of the strained ring system, more specifically the possibility of the nonbonding oxygen orbital for interaction (through space and/or through bond) with the exocyclic π−orbital . Inspection of the eigenvectors resulting from the molecular orbital calculation methods (MINDO/3, MNDO, STO-3G) leaves no doubt that the interaction is primarily a through-bond rather than a through-space interaction. ,, The STO-3G calculation method was also applied to thietan-3-one . These calculations also show considerable electrondensity on the pseudo πCH 2 -orbitals .…”

Section: A Structural Datamentioning

confidence: 99%

“…119 Inspection of the eigenvectors resulting from the molecular orbital calculation methods (MINDO/3, MNDO, STO-3G) leaves no doubt that the interaction is primarily a throughbond rather than a through-space interaction. 119,120,121 The STO-3G calculation method was also applied to thietan-3-one. 121 These calculations also show considerable electrondensity on the pseudo πCH 2 -orbitals.…”

Section: A Structural Datamentioning

confidence: 99%

The Chemistry of Azetidin-3-ones, Oxetan-3-ones, and Thietan-3-ones

et al. 2001

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I. Introduction 29 II. The Chemistry of Azetidin-3-ones 29 A. Structural Data 29 B. Synthetic Methods for Azetidin-3-ones 31 B.1. Carbonyl Group Generation in the Azetidine Ring 31 B.2. Intramolecular Cyclization Reactions 34 B.3. 1,3-Dipolar Cycloaddition Reactions 36 C. Chemical Properties of Azetidin-3-ones 37 C.1. Transformations of the Carbonyl Group 37 C.2. Condensation Reactions − Synthesis of 2-Benzylideneazetidin-3-ones 40 C.3. Ring Transformations of Azetidin-3-ones 40 C.4. Miscellaneous 41 III. The Chemistry of Oxetan-3-ones 42 A. Structural Data 42 B. Synthetic Methods for Oxetan-3-ones 43 B.1. Decomposition of Diazoketones 43 B.2. Oxidation Reactions 44 B.3. Intramolecular Displacement Reactions 46 B.4. Miscellaneous 47 C. Chemical Properties of Oxetan-3-ones 48 C.1. Ring Opening and Ring Expansion of Oxetan-3-ones 48 C.2. Transformations of the Carbonyl Group 49 IV. The Chemistry of Thietan-3-ones 50 A. Synthetic Methods for Thietan-3-ones 51 A.1. Synthesis from Acyclic Precursors 51 A.2. Synthesis by Ring Transformations 53 B. Chemical Properties of Thietan-3-ones 54 B.1. Transformations of the Carbonyl Group 55 B.2. Aldol Reactions 56 B.3. Ring Transformations 56 V. Acknowledgments 58 VI. References 58

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Semiempirical calculations of internal barriers to rotation and ring puckering

Cited by 24 publications

References 13 publications

Dissociation Chemistry of 3-Oxetanone in the Gas Phase

Dissociation Chemistry of 3-Oxetanone in the Gas Phase

Evaluation of MINDO/3 calculations in simple amides, ureas, and heterocycles of biological interest

The Chemistry of Azetidin-3-ones, Oxetan-3-ones, and Thietan-3-ones

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