Molecular orbital calculations on the ethylene episulfide molecule and its isomers

Strausz, O. P.; Gosavi, R. K.; Denes, A. S.; Csizmadia, Imre G.

doi:10.1007/bf01036249

Cited by 13 publications

(5 citation statements)

References 25 publications

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“…CO, -y~: (130) In an attempt to produce methylenecyclopropene (52), the gas-phase pyrolysis and the mercury-sensitized decomposition of c/s-1-methylenecyclopropane-2,3-dicarboxylic anhydride (53) were performed.190 The thermolysis at 720 °C gave the following products: CH2=CHC=CH (46%), CH=CH (5%), CH3C=CH (5%). No evidence for 52 was found.…”

Section: Lee152mentioning

confidence: 99%

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

Braslavsky¹,

Heicklen²

1977

Chem. Rev.

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Section: Lee152mentioning

confidence: 99%

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

Braslavsky¹,

Heicklen²

1977

Chem. Rev.

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“…The three-member cyclic isomer THI itself was the subject of several experimental and theoretical studies, ,− including thermal fragmentation and electrocyclic ring-opening. Two reaction channels were observed by Lown et al for the former reaction.…”

Section: Introductionmentioning

confidence: 99%

“…At temperatures below 250 °C, sulfur and ethylene are formed in stoichiometric yields, while rearrangement to VTH occurs at higher temperatures. The low-temperature reaction follows first-order kinetics, which was interpreted in terms of a pseudo-unimolecular mechanism involving a low-lying triplet excited state of THI. − Thermal decomposition of THI was also investigated by Chin et al in a flow system by following the changes of its photoelectron spectra at various temperatures. Since no observable changes were observed below 600 °C, the difference with the results of ref was ascribed to the much smaller contact times in the flow system than in the static system used by Lown.…”

Section: Introductionmentioning

confidence: 99%

Isomerization and Fragmentation Reactions on the [C₂SH₄] Potential Energy Surface: The Metastable Thione S-Methylide Isomer

et al. 2021

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Thione S-methylide, parent species of the thiocarbonyl ylide family, is a 1,3dipolar species on the [C 2 SH 4 ] potential energy surface, not so much studied as its isomers, thiirane, vinyl thiol, and thioacetaldehyde. The conrotatory ring-closure reaction toward thiirane was studied in the 90s, but no complete analysis of the potential energy surface is available. In this paper, we report a computational study of the reaction scheme linking all species. We employed several computational methods (density functional theory, CCSD(T) composite schemes, and CASSCF/CASPT2 multireference procedures) to find the best description of thione S-methylide, its isomers, and transition states. The barrier from thiirane to thione Smethylide amounts to 52.2 kcal mol −1 (against 17.6 kcal mol −1 for the direct one), explaining why thiocarbonyl ylides cannot be prepared from thiiranes. Conversion of thiirane to vinyl thiol implies a large barrier, supporting why the reaction has been observed only at high temperatures. Fragmentations of thiirane to S( 3 P) or S( 1 D) and ethylene as well as decomposition to hydrogen sulfide plus acetylene were also explored. Triplet and singlet open-shell species were identified as intermediates in the fragmentations, with energies lower than the transition state between thiirane and vinyl thiol, explaining the preference of the latter at low temperatures.

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“…The low-temperature reaction follows first-order kinetics, which was interpreted in terms of a pseudo unimolecular mechanism involving a low-lying triplet excited state of THI. [28][29][30] Thermal decomposition of THI was also investigated by Chin et al 33 in a flow system by following the changes of its photoelectron spectra at various temperatures. Since no observable changes were observed below 600 °C, the difference with the results of ref.…”

Section: Introductionmentioning

confidence: 99%

Isomerization and Fragmentation Reactions on the [C2SH4] Potential Energy Surface. The Metastable Thione-S-Methylide Isomer

Salta¹,

Segovia²,

Katz³

et al. 2020

Preprint

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Thione S-methylide (TSM), the parent species of the thiocarbonyl ylide family, is a 1,3-dipolar, planar species on the [C2SH4] potential energy surface (PES), which has not shared the richness of studies dedicated to its isomers, the cyclic thiirane (THI), and the keto-enol pair vinyl thiol (VTH)/thioacetaldehyde (THA). While the conrotatory ring closure reaction toward THI was studied in the ‘90s, no complete analysis of the PES is available in the literature. In the present paper, we report a computational study of the reaction scheme linking all species on that PES. We employ several levels of calculation, ranging from density functional theory (DFT), through CCSD(T) based composite schemes, to CASSCF/CASPT2 multi-reference procedures, to find the best description of TSM, its isomers, and the transition states (TSs) ruling their interconversion. Fragmentation of TSM, THA and THI were investigated and compared to the available experimental information. We found that the B2PLYP-D3 functional, contrary to M06-2XD3 or B97X-D, describes well the geometry of both TSM and the transition state connecting it to THI. The reverse barrier, from THI to TSM, amounts to 52.2 kcal mol-1 (to be compared to 17.6 kcal mol-1 for the direct one), thus explaining why, in general, thiocarbonyl ylides cannot be prepared from thiiranes. Conversion of THI to VTH implies also a large barrier, explaining why the reaction has been observed only at high temperatures. The fragmentation of THI to S(3P) or S(1D) and ethylene was also explored, together with the decomposition to H2S plus acetylene. Open species, both in triplet and singlet states, were identified as intermediates in the fragmentations, and their energies were found to be lower than the transition state for the isomerization of THI to VTH, thus explaining the preference for fragmentation over isomerization at relatively low temperatures.

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Molecular orbital calculations on the ethylene episulfide molecule and its isomers

Cited by 13 publications

References 25 publications

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

Isomerization and Fragmentation Reactions on the [C₂SH₄] Potential Energy Surface: The Metastable Thione S-Methylide Isomer

Isomerization and Fragmentation Reactions on the [C2SH4] Potential Energy Surface. The Metastable Thione-S-Methylide Isomer

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Molecular orbital calculations on the ethylene episulfide molecule and its isomers

Cited by 13 publications

References 25 publications

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

The gas-phase thermal and photochemical decomposition of heterocyclic compounds containing nitrogen, oxygen, or sulfur

Isomerization and Fragmentation Reactions on the [C2SH4] Potential Energy Surface: The Metastable Thione S-Methylide Isomer

Isomerization and Fragmentation Reactions on the [C2SH4] Potential Energy Surface. The Metastable Thione-S-Methylide Isomer

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Product

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Isomerization and Fragmentation Reactions on the [C₂SH₄] Potential Energy Surface: The Metastable Thione S-Methylide Isomer