Reactions of sulfur atoms. XIV. Ab initio molecular orbital calculations on the ethylene episulfide molecule and the S + C2H4 reaction path

Strausz, O. P.; Gunning, H. E.; Denes, A. S.; Csizmadia, Imre G.

doi:10.1021/ja00779a006

Cited by 23 publications

(13 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sherwood et al explored the kinetics of the addition of S( 1 D 2 ) to ethylene and found that both THI and VTH were formed by a pressure-dependent reaction. Previous studies ,, concluded that addition occurs with a Δ H of 85.0 kcal mol –1 , in reasonable agreement with our Δ(E+ZPE) of 89.6 kcal mol –1 (fragmentation F6 in Table ). However, if this is true, then the energy needed for fragmentation is much larger than that needed to overcome TS2, in contrast with the experimental evidence that dissociation occurs at lower temperatures than isomerization.…”

Section: Resultssupporting

confidence: 92%

“…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%

See 2 more Smart Citations

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

et al. 2021

View full text Add to dashboard Cite

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.

show abstract

Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Unfortunately, very few data of triplet carbenic addition reactions have been reported for the heavy atom effect, but the few available results are in agreement with this prediction. Some supporting evidence comes from the fact that ground sulfur atom (in the 3 P state), whose valence shell is isoelectronic with methylene, adds largely stereospecifically to cis -2-butene. − On the other hand, it was found that triplet nitrene (NH) and triplet oxygen atom (in the 3 P state), which are isoelectronic to the carbene (CH 2 ), always added in a nonstereospecific manner. The reason for this is presumably because the heavy atom effect is relatively unimportant in the first low elements.…”

Section: Resultsmentioning

confidence: 99%

Role of Spin−Orbit Coupling and Symmetry in Triplet Carbenic Addition Chemistry

1996

J. Phys. Chem.

View full text Add to dashboard Cite

The spin-orbit coupling parts in the effective one-electron Hamiltonian operator, with the inclusion of symmetry, have been used to formulate mechanisms based on the Shaik and Epiotis theory in triplet reactions for the radiationless decay of triplet complexes to singlet ground state products. This has been applied to investigate the stereochemical behavior of additions of triplet carbenes to olefins. It is shown that triplet carbene-olefin complexes can be classified according to the number and the direction of the atomic orbital rotations required to maximize spin-orbit coupling and simultaneously maintain the intermolecular binding, from which it may produce different stereoisomers. It is suggested that six spin-inversion reaction mechanisms produce geometric isomers. It is found that, as a direct of the different symmetries of the three sublevels of the triplet state (T x , T y , T z ) and their comparable spin-orbit coupling expressions, the triplet carbene could add to olefins nonstereospecifically. Nevertheless, it is also suggested that, because of its larger spin-orbit coupling expression as well as the less conformational change, the cycloaddition of a triplet carbene to a double bond will lead to the stereospecific cyclopropane with retention of geometry in a concerted pathway. The solvent polarity, substituent effect, and heavy atom effect must all play an important role in determining the stereoconformations of adducts. The results obtained are in agreement with the available experimental results and allow a number of predictions to be made. It is found that the approach proposed in this study is proved to be a good alternative to the traditionally accepted explanation, the Skell-Woodworth mechanism.

show abstract

“…But as yet, the chemical reactivity of atomic sulfur with inorganic and organic molecules remains mostly unexplored. Pioneering kinetic and theoretical work on reactions of S( 3 P, 1 D) with hydrocarbons has shown that, 7,8,9,10,11,12 similarly to the case of O( 1 D) with respect to O( 3 P), S( 1 D) is much more reactive than S( 3 P). 1 The reactions of S( 1 D) may be, in particular, of considerable relevance to atmospheric chemistry, because several reduced sulfur compounds are abundantly released at the Earth's surface from biogenic and other natural sources.…”

Section: Introductionmentioning

confidence: 99%

Observation of organosulfur products (thiovinoxy, thioketene and thioformyl) in crossed-beam experiments and low temperature rate coefficients for the reaction S(1D) + C2H4

Leonori

Petrucci

Balucani

et al. 2009

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The reaction between excited sulfur atoms, S((1)D), and the simplest alkene molecule, ethene, has been investigated in a complementary fashion in (a) crossed-beam dynamic experiments with mass spectrometric detection and time-of-flight (TOF) analysis at a collision energy of 37.0 kJ mol(-1), (b) low temperature kinetic experiments ranging from room temperature down to 23 K, and (c) electronic structure calculations of stationary points and product energetics on the C(2)H(4)S singlet potential energy surface. The rate coefficients for total loss of S((1)D) are found to be very large (ca. 4 x 10(-10) cm(3) molecule(-1) s(-1)) down to very low temperature indicating that the overall reaction is barrier-less. From laboratory angular and TOF distributions at different product masses, three competing reaction channels leading to H + CH(2)CHS (thiovinoxy), H(2) + CH(2)CS (thioketene), and CH(3) + HCS (thioformyl) have been unambiguously identified and their dynamics characterized. Branching ratios have also been estimated. These studies, which exploit the capability of producing intense supersonic beams of sulfur S((3)P,(1)D) atoms and measuring rate coefficients down to very low temperature, offer considerable promise for further dynamical investigations of other sulfur atom reactions of particular relevance to combustion and atmospheric chemistry.

show abstract

Reactions of sulfur atoms. XIV. Ab initio molecular orbital calculations on the ethylene episulfide molecule and the S + C2H4 reaction path

Cited by 23 publications

References 1 publication

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

Role of Spin−Orbit Coupling and Symmetry in Triplet Carbenic Addition Chemistry

Observation of organosulfur products (thiovinoxy, thioketene and thioformyl) in crossed-beam experiments and low temperature rate coefficients for the reaction S(1D) + C2H4

Contact Info

Product

Resources

About

Reactions of sulfur atoms. XIV. Ab initio molecular orbital calculations on the ethylene episulfide molecule and the S + C2H4 reaction path

Cited by 23 publications

References 1 publication

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

Role of Spin−Orbit Coupling and Symmetry in Triplet Carbenic Addition Chemistry

Observation of organosulfur products (thiovinoxy, thioketene and thioformyl) in crossed-beam experiments and low temperature rate coefficients for the reaction S(1D) + C2H4

Contact Info

Product

Resources

About

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