Kinetic isotope effect for the thermally-induced migration of hydrogen in cyclopentadienes

McLean, Stewart; Webster, C. J.; Rutherford, R. J. D.

doi:10.1139/v69-256

Cited by 47 publications

(39 citation statements)

References 6 publications

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“…dence of the H/D kinetic isotope effect for the latter shift seems in agreement with experimental data of McLean et al [31]. The significance of hydrogen atom transfer has been demonstrated in a variety of biochemical reactions.…”

Section: Calculated Ratio Numbers (R(n)) a For Identity Proton Transfsupporting

confidence: 91%

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A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

Buck¹

2008

Int J of Quantum Chemistry

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ABSTRACT:We have studied carbon transfer reactions following an S N 2 reaction profile. With ab initio calculations and experimental geometries concerning the nature of the various complexes indicated as stable, intermediate, and transition state we were able to show the additional value of van't Hoff's tetrahedral configuration by changing its geometry via a trigonal pyramid into a trigonal bipyramid. The ratio of the apical bond and corresponding tetrahedral bond distances is then nearly 1.333. The relevance of this approach has also been shown for identity proton-(hydrogen atom-, and hydride-) in-line reactions. The use of this geometrical transmission will be demonstrated for the hydrogen bonding distances in e.g., DNA duplexes and other biological (supra) molecular systems.

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Section: Calculated Ratio Numbers (R(n)) a For Identity Proton Transfsupporting

confidence: 91%

“…On the other hand Shelton et al found with their calculations tunneling in the 1,5 H‐shift of 1,3‐cyclopentadiene and 5‐methyl‐1,3‐cyclopentadiene 30. The calculated temperature dependence of the H/D kinetic isotope effect for the latter shift seems in agreement with experimental data of McLean et al 31.…”

Section: Resultsmentioning

confidence: 99%

A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

Buck¹

2008

Int J of Quantum Chemistry

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“…The activation energy difference can be explained by the relatively small endothermicity of the 2-MCP to 1-MCP isomerization compared to the 1-MCP to 5-MCP isomerization. The values of activation energy are consistent with the experimental results reported by McLean et al [30]. Therefore, the reaction rate constant k can be calculated based on Transition State Theory using Eq.…”

Section: Isomerization Reactionsupporting

confidence: 89%

Molecular simulation studies on chemical reactivity of methylcyclopentadiene

Wang

Zhang

Rogers

et al. 2009

Journal of Hazardous Materials

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“…Whereas the energy barrier for H-atom shifts in methyl indene, as is shown on the various isomerization surfaces, is around 39 kcal/mol, the equivalent process in methyl cyclopentadiene is onlỹ 20 kcal/mol (experiment) 16 and ~23.3 kcal/mol (quantum chemical calculations), 17 respectively. Hatom shift in cyclopentadiene is 23.6 kcal/mol.…”

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confidence: 89%

Ring expansion and isomerization in methyl indene and methylene indene radicals. Quantum chemical and transition‐state theory calculations

Dubnikova

Lifshitz

2003

Israel Journal of Chemistry

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Ring expansion and isomerization in 1‐ and 2‐methylene indene radicals and isomerizations among the three isomers of methyl indene were studied by the Becke three‐parameter hybrid method with Lee‐Yang‐Parr correlation functional approximation (B3LYP). Structure, energy, and frequency calculations were carried out with the Dunning correlation consistent polarized doubleζ, (cc‐pVDZ) basis set. In contrast to methyl cyclopentadiene, transition states for ring expansion starting from the molecule methyl indene could not be located. The potential energy surfaces for ring expansion in methylene indene radicals consist of several intermediates and transition states and involve two principal pathways. One pathway is associated with cleavage of the five‐membered ring adjacent to the methylene group and formation of a six‐membered ring. In the second pathway, the transition states of the first stage consist of a newly‐formed three‐membered ring fused to the original cyclopentadiene ring. In all cases, the reaction pathways leading to ring expansion include an intermediate that, via an additional transition state, produces an α‐ or (β‐hydronaphthalene radical. The latter, by a fast H‐atom ejection, forms naphthalene. The structure, energetics, and additional parameters on the potential energy surfaces are shown. Several transition states and intermediates are common to both ring expansion and isomerization, so that there are competing parallel pathways that determine the final distribution among the isomerization and ring expansion products. Potential energy surfaces for interisomerization among the various isomers of methyl indene were calculated, and several reaction pathways were suggested.

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Kinetic isotope effect for the thermally-induced migration of hydrogen in cyclopentadienes

Cited by 47 publications

References 6 publications

A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

A combined experimental, theoretical, and Van't Hoff model study for identity methyl, proton, hydrogen atom, and hydride exchange reactions. Correlation with three‐center four‐, three‐, and two‐electron systems

Molecular simulation studies on chemical reactivity of methylcyclopentadiene

Ring expansion and isomerization in methyl indene and methylene indene radicals. Quantum chemical and transition‐state theory calculations

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