Ab Initio Studies of Thermal Syn-Elimination Reactions in Carbonates:  Effect of Structure on Reactivity

Speybroeck, Véronique Van; Martelé, Yves; Schacht, Etienne; Waroquier, Michel

doi:10.1021/jp0259723

Cited by 6 publications

(6 citation statements)

References 34 publications

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“…level underestimate the influence of substitution effects, they do correctly predict that rearrangement rates are (i) more sensitive to aryl substitution at the a position on the carbonate alkyl chain, as opposed to the b position and (ii) show contrasting sensitivity to electron-withdrawing versus electron-donating substituents. Van Speybroeck et al, [51] who previously studied these reactions at the B3LYP/6-311G(d,p) level, noted these same trends and used them reasonably to conclude that the TS structure has more C-O bond breaking, with development of carbocationic character at the a position, than any corresponding bond making. Owing to the complexity of the substituted carbonates, Van Speybroeck et al developed initial geometries from PM3 calculations in order to be more efficient.…”

Section: Resultsmentioning

confidence: 79%

Theoretical prediction of linear free energy relationships using proton nucleomers

Macchia

Gagliardi

Carlson

et al. 2007

J of Physical Organic Chem

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Values of s and s R , for use in linear free energy relationships, are determined for para hydrogen atoms having nuclear charges other than 1 (nucleomers). Hammett r values for a variety of free energies of activation, reaction, and other extrathermodynamic properties (e.g., vibrational frequencies) are computed therefrom and compared to those computed using typical para functional groups. The nucleomer correlations show excellent qualitative agreement with standard correlations but the quantitative agreement is less good, typically underestimating the standard r-value by 10-60%.

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Section: Resultsmentioning

confidence: 79%

Theoretical prediction of linear free energy relationships using proton nucleomers

Macchia

Gagliardi

Carlson

et al. 2007

J of Physical Organic Chem

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“…Stabilization of the positive charge in the C α position affects acceleration of the reaction rate. The last step is a β-H-elimination or syn -elimination. , …”

Section: Resultsmentioning

confidence: 99%

“…The last step is a β-H-elimination or syn-elimination. 21,22 According to this mechanism, it is possible to tune the elimination temperature by changing the cation-stabilizing properties of the side chain. Based on this rationale, we set out to prepare derivatives changing the alkyl into an alkenyl (6h− 6j) or alkinyl (6e−6g) side chains, which form mesomerically stabilized cations and eventually lead to conjugated double bonds after elimination.…”

Section: Introductionmentioning

confidence: 99%

Tertiary Carbonate Side Chains: Easily Tunable Thermo-labile Breaking Points for Controlling the Solubility of Conjugated Polymers

et al. 2015

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Breakpoints are not exclusive to tennis: We present a new class of solubilizing groups for conjugated polymers which enable solution processing of multi-layer devices. Conjugated polymers in organic devices are sometimes difficult to process due to their limited solubility. Well soluble polymers decorated with alkyl side chains, however, introduce new challenges for thin-film deposition: Using the same solvent for multiple layers can dissolve the already applied layers. In this work we introduce a new class of thermo-labile groups which reduce the solubility of conjugated polymers after thermal treatment. Following a very modular approach, we can tune the temperature of the thermo-cleavage between 140 and 200 °C.

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“…Several ab initio and density functional theory (DFT) studies − have been performed to analyze the special characteristics of this reaction in different molecules. To carry out this task, analyses of the energies, atomic charges, kinetic parameters, and relative lengthening of the bonds have been done.…”

Section: Introductionmentioning

confidence: 99%

Ab Initio MP2 and DFT Study of the Thermal Syn Elimination Reaction in Ethyl Formate

2003

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The thermal elimination reaction that appears in some polycarbonates has been studied by density functional theory (DFT) and ab initio methods of different levels. This work has been focused in the elimination process of ethyl formate, as a good model of this kind of reaction. Different minima and the transition state have been found to characterize the thermal elimination reaction, and the activation energy has been obtained. In this study, we have used different methods to calculate the contribution of the correlation energy; different basis sets were also employed. This will allow us to perform an analysis of the influence of the applied method in the obtained results to study the thermal elimination. The lengthening of the bonds has also been analyzed to shown how concerted the thermal elimination is in the ethyl formate. Three minima have been found for the ethyl formate, two of them are very close and the third is higher in energy. In general, the DFT method with a B3LYP functional gives a less concerted reaction. A nonplanar transition state is predicted by most of the methods used.

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Ab Initio Studies of Thermal Syn-Elimination Reactions in Carbonates: Effect of Structure on Reactivity

Cited by 6 publications

References 34 publications

Theoretical prediction of linear free energy relationships using proton nucleomers

Theoretical prediction of linear free energy relationships using proton nucleomers

Tertiary Carbonate Side Chains: Easily Tunable Thermo-labile Breaking Points for Controlling the Solubility of Conjugated Polymers

Ab Initio MP2 and DFT Study of the Thermal Syn Elimination Reaction in Ethyl Formate

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