The Thermal Decomposition of Cyclobutane<sup>1,2</sup>

Genaux, Charles T.; Kern, Fritz; Walters, W. D.

doi:10.1021/ja01120a025

Cited by 86 publications

(25 citation statements)

References 7 publications

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“…We omit from consideration 2 π s +2 π s thermally disallowed concerted pathways due to the exceptionally high activation energy (~115 kcal/mol) determined by Woodward and Hoffmann 49 (in that this is significantly higher than the activation energy of cyclobutane ~62 kcal/mol 50 ).…”

Section: Resultsmentioning

confidence: 99%

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

et al. 2013

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A primary goal of covalent mechanochemistry is to develop polymer bound mechanophores that undergo constructive transformations in response to otherwise destructive forces. The [2+2] cycloreversion of cyclobutane mechanophores has emerged as a versatile framework to develop a wide range of stress-activated functionality. Herein, we report the development of a class of cyclobutane bearing bicyclo[4.2.0]octane mechanophores. Using carbodiimide polyesterification, these stress-responsive units were incorporated into high molecular weight polymers containing up to 700 mechanophores per polymer chain. Under exposure to the otherwise destructive elongational forces of pulsed ultrasound, these mechanophores unravel by ~7 Å per monomer unit to form α,β-unsaturated esters that react constructively via thiol-ene conjugate addition to form sulfide functionalized copolymers and cross-linked polymer networks. To probe the dynamics of the mechanochemical ring opening, a series of bicyclo[4.2.0]octane derivatives that varied in stereochemistry, substitution, and symmetry were synthesized and activated. Reactivity and product stereochemistry was analyzed by 1H NMR, which allowed us to interrogate the mechanism of the mechanochemical [2+2] cycloreversion. These results support that the ring opening is not concerted, but proceeds via a 1,4 diradical intermediate. The bicyclo[4.2.0]octanes hold promise as active functional groups in new classes of stress-responsive polymeric materials.

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Section: Resultsmentioning

confidence: 99%

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

et al. 2013

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“…For the allowed 4+2 reaction of butadiene and ethylene to cyclohexene ReaxFF gives a good reproduction of the reaction barrier (ReaxFF: 33 kcal/mol; HF/ 6-31G**/MP4: 25 kcal/mol). However, for the 2+2 reaction of two ethylene molecules to cyclobutane ReaxFF fails to fully reproduce the increase in reaction barrier by allowing the forbidden planar approach pathway (ReaxFF: 39 kcal/mol; experimental barrier: 69 62.5 kcal/mol). Keeping these limitations in mind ReaxFF provides a useful tool for studying hydrocarbon reactivity.…”

Section: Discussionmentioning

confidence: 99%

ReaxFF: A Reactive Force Field for Hydrocarbons

et al. 2001

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To make practical the molecular dynamics simulation of large scale reactive chemical systems (1000s of atoms), we developed ReaxFF, a force field for reactive systems. ReaxFF uses a general relationship between bond distance and bond order on one hand and between bond order and bond energy on the other hand that leads to proper dissociation of bonds to separated atoms. Other valence terms present in the force field (angle and torsion) are defined in terms of the same bond orders so that all these terms go to zero smoothly as bonds break. In addition, ReaxFF has Coulomb and Morse (van der Waals) potentials to describe nonbond interactions between all atoms (no exclusions). These nonbond interactions are shielded at short range so that the Coulomb and van der Waals interactions become constant as R ij f 0. We report here the ReaxFF for hydrocarbons. The parameters were derived from quantum chemical calculations on bond dissociation and reactions of small molecules plus heat of formation and geometry data for a number of stable hydrocarbon compounds. We find that the ReaxFF provides a good description of these data. Generally, the results are of an accuracy similar or better than PM3, while ReaxFF is about 100 times faster. In turn, the PM3 is about 100 times faster than the QC calculations. Thus, with ReaxFF we hope to be able to study complex reactions in hydrocarbons.

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“…Therefore, the initial reaction of 1 leading to the formation of 2 is the formation of a biradical TS (TS1) whose subsequently fragmentation yields acyclic 2 (Scheme 4). The reported activation parameters for k 1 and k 2 are reported to be typical for fragmentation of four-membered rings [48,[53][54][55].…”

Section: Tablementioning

confidence: 96%

Kinetic and mechanistic aspects of myrcene production via thermal-induced β-pinene rearrangement

Stolle

Bonrath

Ondruschka

2008

Journal of Analytical and Applied Pyrolysis

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The Thermal Decomposition of Cyclobutane^1,2

Cited by 86 publications

References 7 publications

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

ReaxFF: A Reactive Force Field for Hydrocarbons

Kinetic and mechanistic aspects of myrcene production via thermal-induced β-pinene rearrangement

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The Thermal Decomposition of Cyclobutane1,2

Cited by 86 publications

References 7 publications

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

Stress-Responsive Polymers Containing Cyclobutane Core Mechanophores: Reactivity and Mechanistic Insights

ReaxFF: A Reactive Force Field for Hydrocarbons

Kinetic and mechanistic aspects of myrcene production via thermal-induced β-pinene rearrangement

Contact Info

Product

Resources

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The Thermal Decomposition of Cyclobutane^1,2