Fluxional nature in cyclohexane and cyclopentane: spherical conformational landscape model revisited

Sakhaee, Sahar; Sakhaee, Mohammad Hossein; Takallou, Ahmad; Forouzanfar, Fatemeh; Sakhaee, Nader

doi:10.1007/s12039-019-1701-y

Cited by 5 publications

(3 citation statements)

References 33 publications

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“…As proposed in previous studies, [9, 21, 31] cyclohexane is a fluxional, highly symmetrical, and almost strain‐free molecule, of which the stable chair and twist‐boat conformers have D 3d and D 2 symmetries, respectively. Their structural characteristics determine that there are two and three discernible types of positions available for substituents occupying, as noted above.…”

Section: Resultsmentioning

confidence: 84%

“…These previous studies usually cover two mainly aspects: (1) conformational determination of the simple neutral cycloalkane compounds from three‐membered ring to the larger ones, like cyclohexane, cyclooctane, and cyclotridecane [10, 15, 16]; (2) conformational changing investigation of cyclohexane and its substitution derivatives [1, 5, 12, 14, 17‐19]. Since cyclohexane has a fluxional and most symmetrical structure, it serves as the archetype molecule to understanding the energetics and conformational preferences for other related cycloalkanes and yielded derivatives [20, 21]. According to the prior researches, [9, 10, 20] the distortion of cyclohexane ring typically generates four distinct molecular configurations, that is, chair, twist‐boat, half‐chair, and boat conformers, and they could accomplish interconversion via inversion‐topomerization process.…”

Section: Introductionmentioning

confidence: 99%

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Computational study of inversion‐topomerization pathways in 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane: Ab initio conformational analysis

Bian

Zhang

Wang

et al. 2021

Int J of Quantum Chemistry

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This work concerns the special conformational behaviors for di‐substituted cyclohexanes that inherently depend on spatial orientations of side chains in flexible cyclic ring. The 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane in both cis‐ and trans‐configurations were focused here to unravel their inversion‐topomerization mechanisms. Full geometry optimizations were separately performed at B3LYP/6‐311++G(d,p) and MP2/6‐311++G(d,p) levels to explicitly identify all distinguishable molecular structures, and thereby the complete interconversion routes were carefully explored. Additional quantum calculations were carried out by G4 and CCSD(T)/6‐311++G(d,p) methods to acquire high‐level single point energies. With respect to quantum results, conformational analysis was conducted to study determinations, thermodynamic stabilities, and relative energies of distinct conformers. Temperature‐dependent populations of local minima for each dimethylcyclohexane were computed by Boltzmann distribution within 300–2500 K. Moreover, their unique inversion and topomerization processes were fully investigated, and potential energy surfaces were illustrated with the rigorous descriptions in two or three‐dimensional schemes for clarify.

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Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Computational study of inversion‐topomerization pathways in 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane: Ab initio conformational analysis

Bian

Zhang

Wang

et al. 2021

Int J of Quantum Chemistry

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“…This would improve the face-to-face aggregation if the molecule is plane enough, but it is well known that the union of two cyclopentane structureslike in the CCC moleculeis highly flexible. 72,73 In Figure 3, the angles between the adjacent five-membered rings in the center of the molecule were measured by sampling the angle between the planes formed by the two shared carbons and the opposite carbon in each ring. The CCC molecule is the one with the smaller angle between the aromatic cores.…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

et al. 2021

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This study is focused on evaluating the aggregation behavior of four asphaltene molecules (PA3-type) dissolved in three different solvents. Hence, solution models composed of asphaltenes dissolved in toluene, n-heptane, and mixtures of n-heptane and toluene (known as heptol), were evaluated with molecular dynamics (MD) simulations. For MD calculations, four PA3-type structures were chosen to evaluate the effect of the location of one heteroatom in the polyaromatic core on the aggregation behavior. The first structure consists of only a CH structure, the second has sulfur, the third has nitrogen, and the last one contains oxygen. The heteroatom was replaced in the same location in one of the five-membered rings in the center of the molecule to test the different chemical effects induced by these heteroatoms. Molecules with the heteroatoms showed a higher aggregation tendency in n-heptane than in heptol-50 and toluene, with an average size of 12.8, 6.2, and 2.4 molecules per aggregate, respectively, whereas the PA3 molecule with no heteroatom forms less and smaller aggregates. The inclusion of only one heteroatom increases the polarity and the planarity of the molecule, increasing the attractive interaction energies (140−160% in n-heptane) and the overall aggregation tendency. The molecule with the sulfur heteroatom forms bigger and more stable aggregates than molecules with oxygen and nitrogen. In conclusion, the inclusion of heteroatoms in the PA3 structure increases the polarity and planarity of the molecule, improving the aggregation tendency in all solvents, notoriously in n-heptane.

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Redox potentials of puckered 1,4-benzoquinone

Jayachandran¹,

Angamuthu

Gopalan³

2022

J Chem Sci

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Fluxional nature in cyclohexane and cyclopentane: spherical conformational landscape model revisited

Cited by 5 publications

References 33 publications

Computational study of inversion‐topomerization pathways in 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane: Ab initio conformational analysis

Computational study of inversion‐topomerization pathways in 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane: Ab initio conformational analysis

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

Redox potentials of puckered 1,4-benzoquinone

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