Unimolecular rearrangements connecting hydroxyethylidene (CH3-C-OH), acetaldehyde (CH3-CH:O), and vinyl alcohol (CH2:CH-OH)

Smith, Brian J.; Nguyen, Minh Tho; Bouma, Willem J.; Radom, Leo

doi:10.1021/ja00017a015

Cited by 123 publications

(126 citation statements)

References 36 publications

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“…Our initial study [1] of the lowestlying triplet PES examined pathways 1-9 from the Nguyen et al [6] work as well as an additional path 10. The current study expands this earlier work [1] by examining multireference barriers for the lowest-lying singlet paths [10][11][12][13]20 as labeled in Nguyen et al [6], excited states for path 1, the Miyoshi path (M), and important surface crossings. In particular, this study examines the following reactions: .…”

Section: Introductionmentioning

confidence: 64%

“…All coupling constants along this path are less than 4 cm -1 . These SOC constants do not match the (10,9) CAS couplings near Á CH 2 CH 2 O Á since the (8,8) CAS does not contain some states of interest due to its lack of the O2p in the active space. Figure 10 shows this region of the PES from these calculations.…”

Section: Pathway Miyoshi M and 20mentioning

confidence: 96%

“…Thus, these four states (two triplets and two singlets) will prove very important in determining any dynamics for this system. Energy (kcal/mol) S value (bohr*sqrt(amu)) Energy (kcal/mol) S value (bohr*sqrt(amu)) (10,9) SA CAS on the Á CH 2 CH 2 O Á biradical half of the path. Figure 9 shows the energetics for this hydrogen migration at the (8,8) SO-CASCI level.…”

Section: Pathway Miyoshi M and 20mentioning

confidence: 99%

“…Several initial theoretical studies of this reaction are present in the literature [7][8][9][10][11]. This work was followed by the calculations of Nguyen et al [6] considered above and those of Hu et al [12], who studied the reaction in substantial detail at different levels of theory on both the triplet and singlet PESs.…”

Section: Introductionmentioning

confidence: 99%

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O + C2H4 potential energy surface: excited states and biradicals at the multireference level

West

Lynch²,

Sellner

et al. 2012

Theor Chem Acc

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The focus of this study is to understand the multiconfigurational nature of the biradical species involved in the early reaction paths of the oxygen plus ethylene PES. In previous work (J Phys Chem A 113, 12663, 2009), the lowest-lying O( 3 P) ? C 2 H 4 PES was extensively explored at the MCSCF, MRMP2, and MR-AQCC levels of theory. In the current work, ground and excited, triplet-and singlet-state reaction paths for the initial addition of oxygen to ethylene were found at the MCSCF and MRMP2 levels along with five singlet pathways near the Á CH 2 CH 2 O Á biradical at the MCSCF, MRMP2, and CR-CC(2,3) levels. One of these five paths can lead to the CH 2 CO ? H 2 products from CH 3 CHO rather than from the Á CH 2 CH 2 O Á biradical, and this pathway was investigated with a variety of CAS sizes. To provide further comparison between the MRMP2 and CR-CC(2,3) levels, MR-AQCC single-point energies and optimizations were performed for select geometries. After the initial exploration of this region of the surface, the lowest singlettriplet surface crossings were explicitly determined at the MCSCF level. Additional MRMP2 calculations were performed to demonstrate the limitations of single-state perturbation theory in this biradical region of the PES, and SO-MCQDPT2 single-point energies using SA MCSCF were calculated on a grid of geometries around the primary surface crossing. In particular, these calculations were examined to determine a proper active space and a physically reasonable number of electronic states. The results of this examination show that at least four states must be considered to represent this very complex region of the PES.

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Section: Introductionmentioning

confidence: 64%

Section: Pathway Miyoshi M and 20mentioning

confidence: 96%

Section: Pathway Miyoshi M and 20mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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O + C2H4 potential energy surface: excited states and biradicals at the multireference level

West

Lynch²,

Sellner

et al. 2012

Theor Chem Acc

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“…[17] At the G-1 [18] level of theory, acetaldehyde is found to be 47.0 kcal·mol Ϫ1 lower in energy than vinyl alcohol; in the imineϪenamine case, the relative energy is only 3.8 kcal·mol Ϫ1 in favor of acetaldimine. [19] Theoretical studies exhibit the general trend that the computed relative energies and activation energies in imineϪenamine interconversions are both lower than those in the corresponding ketoϪenol processes. We have reported [20] our studies of substituent effects in the tautomerism of acetaldimine at the MP4/6Ϫ31ϩϩG**//MP2(full)/6Ϫ31G* and G-2 levels.…”

Section: ϫ8mentioning

confidence: 97%

Computational Study on the Effects of Substituents and Functional Groups in the Isomerization of 1‐ and 2‐Substituted Propenes, Acetaldimines, and Aldehydes

Chuang

Lien

2004

Eur J Org Chem

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We have performed ab initio molecular orbital calculations on 1-and 2-substituted propenes, acetaldimines, and aldehydes -H 3 CC(X)=Y and XCH 2 CH=Y (Y = CH 2 , NH, O; X = H, CH 3 , NH 2 , OH, F) -to investigate the effects that substituents and functional groups have on their isoelectronic (except X = H) tautomerism. Structures for all stationary points (keto forms, enol forms, and transitions states) were optimized at the HF/6−31G**, MP2(full)/6−31G*, and B3LYP/6−31G** levels of theory and were characterized by frequency calculations. We performed intrinsic reaction coordinate (IRC) calculations at the HF/6−31G** level of theory to connect the transition structures with their local minima along the reaction path. In the transition structures, the migrating H4 atom is slightly out of plane, with a dihedral angle H4−C2−C1−Y3 (d4) of Ͻ 12°. In the keto−enol and imine−enamine series, the keto forms are thermodynamically more stable than their counterparts by ca. 30 kcal·mol −1 re-

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A theoretical study on keto-enol tautomerization involving simple carbonyl derivatives

et al. 1997

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Unimolecular rearrangements connecting hydroxyethylidene (CH3-C-OH), acetaldehyde (CH3-CH:O), and vinyl alcohol (CH2:CH-OH)

Cited by 123 publications

References 36 publications

O + C2H4 potential energy surface: excited states and biradicals at the multireference level

O + C2H4 potential energy surface: excited states and biradicals at the multireference level

Computational Study on the Effects of Substituents and Functional Groups in the Isomerization of 1‐ and 2‐Substituted Propenes, Acetaldimines, and Aldehydes

A theoretical study on keto-enol tautomerization involving simple carbonyl derivatives

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