Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Rayne, Sierra; Forest, Kaya

doi:10.1007/s00214-016-1837-5

Cited by 6 publications

(6 citation statements)

References 59 publications

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“…The edge zigzag and armchair carbon atoms were terminated with hydrogen atoms. Notably, in agreement with previous data, the energetically favourable electronic structure of the graphene sheet used in this study was calculated …”

Section: Methodssupporting

confidence: 87%

Fast Degradation for High Activity: Oxygen‐ and Nitrogen‐Functionalised Carbon Nanotubes in Solid‐Acid Fuel‐Cell Electrodes

Naumov

Flyunt

et al. 2016

ChemSusChem

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Similar to polymer electrolyte membrane fuel cells, the widespread application of solid acid fuel cells (SAFCs) has been hindered partly by the necessity of the use of the precious-metal catalyst Pt in the electrodes. Here we investigate multi-walled carbon nanotubes (MWCNTs) for their potential catalytic activity by using symmetric cell measurements of solid-acid-based electrochemical cells in a cathodic environment. For all measurements, the carbon nanotubes were Pt free and subject to either nitrogen or oxygen plasma treatment. AC impedance spectroscopy of the electrochemical cells, with and without a DC bias, was performed and showed significantly lower initial impedances for oxygen-plasma-treated MWCNTs compared to those treated with a nitrogen plasma. In symmetric cell measurements with a DC bias, the current declines quickly for oxygen-plasma-treated MWCNTs and more slowly, over 12 days, for nitrogen-plasma-treated MWCNTs. To elucidate the degradation mechanisms of the oxygen-plasma-treated MWCNTs under SAFC operating conditions, theoretical calculations were performed using DFT. The results indicate that several degradation mechanisms are likely to occur in parallel through the reduction of the surface oxygen groups that were introduced by the plasma treatment. This finally leads to an inert MWCNT surface and a very low electrode performance. Nitrogen-plasma-treated MWCNTs appear to have a higher stability and may be worthwhile for future investigations.

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Section: Methodssupporting

confidence: 87%

Fast Degradation for High Activity: Oxygen‐ and Nitrogen‐Functionalised Carbon Nanotubes in Solid‐Acid Fuel‐Cell Electrodes

Naumov

Flyunt

et al. 2016

ChemSusChem

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“…As mentioned in the Introduction, the generation of DHTs reported here is a single photon, two steps process. The general features of the photoinduced heterolysis of chlorobenzenes via the triplet state are well-known, , as is the fact that a nucleophilic solvent (such as water) stabilizes the intermediate triplet phenyl cation, ,,, thus favoring the occurrence of its peculiar reactions (e.g., hydrogen abstraction from the medium). However, cleavage of the C–Si bond may take place competitively, leading to the corresponding DHTs.…”

Section: Discussionmentioning

confidence: 99%

“…The consumption of 1a – c was significant (apart selected cases) in all of the protic media tested herein (Tables , ), also when additives, such as tetrachloromethane or 1,4-cyclohexadiene, were present (Table ). The desired desilylation to α, n -DHTs suffered, however, of competing chemistry ,, from the short-lived (a lifetime of 10 ns could be estimated) triplet phenyl cations ( 3 VI + a – c , Scheme ).…”

Section: Discussionmentioning

confidence: 99%

Singlet vs Triplet Reactivity of Photogenerated α,n-Didehydrotoluenes

et al. 2017

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The reactivity of α,n-didehydrotoluenes (DHTs) in protic media (organic/aqueous mixtures) was explored by means of a combined computational and experimental approach. These intermediates were generated via a photoinduced double elimination process occurring in (chlorobenzyl)trimethylsilanes and led to the formation of a varied products distribution, depending on the isomer tested. Irradiation of ortho- and para-derivatives resulted, respectively, in the formation of triplet α,2- and α,4-DHTs, whose diradical reactivity led to both radical and polar products. On the other hand, irradiation of the meta-precursor led to the singlet α,3-DHT isomer. The latter showed a marked preference for the formation of polar products and this was rationalized, as supported by computational evidence, via the involvement of a zwitterionic species arising through interaction of the nucleophilic solvent with the benzylic position of the DHT.

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“…The error is only 1.83 kcal/mol, which is still within the method's accuracy based on Ref. [61]. In the case of B3LYP, the addition of dispersion correction (GD3) improves the accuracy.…”

Section: Chemistryselectmentioning

confidence: 65%

Acetylcholine Conformational Flexibility and Its Neutral Hydrolysis in Aqueous Solution

et al. 2023

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Enzymatic hydrolysis is the main target to deal with ACh depletion. However, a recent study indicates that the nonenzymatic one may contribute to the depletion. This study highlights the necessity of considering possible conformers, discrete-continuum models, and dispersive effects for investigating the neutral (non-enzymatic) hydrolysis of flexible molecules in aqueous solution. We systematically built the possible conformers within the first-principles framework. The results confirm the reactivity of high-energy ACh conformer towards neutral hydrolysis. We proposed that conformational changes occur before the hydrolysis. The calculated activation and reaction energy shows that the discrete-continuum solvation model gives the closest result to experimental observations. This study also shows that neglecting dispersive effects brings unreliable structures in the initial state, which leads to unreliable activation energy.

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Singlet–triplet excitation energies of substituted phenyl cations: a G4(MP2) and G4 theoretical study

Cited by 6 publications

References 59 publications

Fast Degradation for High Activity: Oxygen‐ and Nitrogen‐Functionalised Carbon Nanotubes in Solid‐Acid Fuel‐Cell Electrodes

Fast Degradation for High Activity: Oxygen‐ and Nitrogen‐Functionalised Carbon Nanotubes in Solid‐Acid Fuel‐Cell Electrodes

Singlet vs Triplet Reactivity of Photogenerated α,n-Didehydrotoluenes

Acetylcholine Conformational Flexibility and Its Neutral Hydrolysis in Aqueous Solution

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