Computational and Matrix Isolation Studies of Tetra‐<i>tert</i>‐butylethane

Bucher, Götz

doi:10.1002/ejoc.200900378

Cited by 4 publications

(2 citation statements)

References 34 publications

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“…The results indicate that the reaction should be quite facile, easily occurring on a sub-μs time scale. We note that the M05−2X functional, which has been reported to give results far better than B3LYP, , gives a lower value for the activation enthalpy. The results are shown in Figure .…”

Section: Resultsmentioning

confidence: 71%

Quenching of Triplet Benzophenone by Benzene and Diphenyl Ether: A DFT Study

Smith

Bucher

2010

J. Phys. Chem. A

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The reaction of triplet benzophenone with benzene and diphenyl ether has been studied by density functional theory. Quenching of the triplet ketone is predicted to occur by addition of the carbonyl oxygen to the arene chromophores. The reaction is accompanied by a significant degree of charge transfer. In case of the reaction of triplet benzophenone with diphenyl ether (DPE), addition is predicted to occur preferentially at the ortho position of the DPE molecule. Addition to the ipso-position of DPE, which provides a pathway for formation of the phenoxy radical, is predicted to occur as a minor reaction pathway.

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Section: Resultsmentioning

confidence: 71%

Quenching of Triplet Benzophenone by Benzene and Diphenyl Ether: A DFT Study

Smith

Bucher

2010

J. Phys. Chem. A

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“…All calculations were performed using Truhlar's M05-2X functional 16 , which has been shown by us 15,17,18 and others 19 to give excellent thermochemical results. For geometry optimisations, a 6-31G(d) basis set 20 was utilized.…”

Section: Methodsmentioning

confidence: 99%

Intramolecular addition of oxyradicals to benzene rings: A DFT study

Bucher

2011

Collect. Czech. Chem. Commun.

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This work is dedicated to Professor Pavel Kočovský on the occasion of his 60th birthday.The reactivity of a series of oxyradicals related to the triplet state of β-phenylpropiophenone was investigated by density functional theory. Analysis of the potential energy hypersurfaces indicates that radical addition to the β-phenyl ring should occur with a smaller barrier than intramolecular hydrogen abstraction from the benzylic position, although the latter reaction is far more exothermic. Addition can occur in ipso-and ortho-position of the β-phenyl ring, with ortho addition being slightly more favourable. As both addition reactions are predicted to be mildly exothermic and exergonic, intermolecular trapping of the resulting cyclohexadienyltype radicals should be feasible.

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Can tetra‐tert‐butylethylene be formed by ion–ion recombination or ion–molecule reaction of two di‐tert‐butylcarbene units?—a DFT study

Kanawati¹,

Lenoir²,

Schmitt‐Kopplin³

2011

J of Physical Organic Chem

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The reaction channels of di‐tert‐butylcarbene (2), its radical anion, (3) and its radical cation (4) were investigated theoretically by using DFT/B3LYP with 6‐31+G(d) basis set and 6‐311+G(2d,p) for single point energy calculations. Conversion of the neutral carbene 2 to the charged species 3 and 4 results in significant geometric changes. In cation 4 two different types of C(CH3)3 bonds are observed: one elongated sigma bond called “axial” with 1.61 Å and two normal sigma bonds with a bond length of 1.55 Å. Species 2 and 4 have an electron deficient carbon center; therefore, migration of CH3 and H is observed from adjacent tert‐butyl groups with low activation energies in the range of 6–9 kcal/mol like similar Wagner–Meerwein rearrangements in the neopentyl‐cation system. Neutral carbene 2 shows CH insertion to give a cyclopropane derivative with an activation energy of 6.1 kcal/mol in agreement with former calculations. Contrary to species 2 and 4, the radical anion 3 has an electron rich carbon center which results in much higher calculated activation energies of 26.3 and 42.1 kcal/mol for H and CH3 migrations, respectively. NBO charge distribution indicates that the hydrogen migrates as a proton. The central issue of this work is the question: how can tetra‐tert‐butylethylene (1) be prepared from reaction of either species 2, 3, or 4 as precursors? The ion–ion reaction between 3 and 4 to give alkene 1 with a calculated reaction enthalpy of 203.5 kcal/mol is extremely exothermic. This high energy decomposes alkene 1 after its formation into two molecules of carbene 2 spontaneously. Ion–molecule reaction of radical anion 3 with the neutral carbene 2 is a much better choice: via a proper oriented charge–transfer complex the radical anion of tetra‐tert‐butylethylene (11) is formed. The electron affinity of 1 was calculated to be negligible. Copyright © 2010 John Wiley & Sons, Ltd.

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Computational and Matrix Isolation Studies of Tetra‐tert‐butylethane

Cited by 4 publications

References 34 publications

Quenching of Triplet Benzophenone by Benzene and Diphenyl Ether: A DFT Study

Quenching of Triplet Benzophenone by Benzene and Diphenyl Ether: A DFT Study

Intramolecular addition of oxyradicals to benzene rings: A DFT study

Can tetra‐tert‐butylethylene be formed by ion–ion recombination or ion–molecule reaction of two di‐tert‐butylcarbene units?—a DFT study

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