Formation Mechanism of NF<sub>4</sub><sup>+</sup> Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids

Haiges, Ralf; Vasiliu, Monica; Dixon, David A.

doi:10.1002/ange.201701784

Cited by 4 publications

(1 citation statement)

References 55 publications

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“…We predict that SO 3 is a stronger Lewis acid than SO 2 by approximately 35 kcal/mol at the CCSD(T)/CBS// MP2/a(T+d) level based on a calculated fluoride affinity of SO 3 of 90.0 kcal/mol. On the basis of the fluoride affinity of the strong Lewis acid SbF 5 (107.5 kcal/mol), 72 we conclude that SO 3 is a moderate Lewis acid, whereas SO 2 is a much weaker Lewis acid. The experimental proton affinity of H 2 S (168.5 ± 1.3 kcal/mol) 73 is higher than that of H 2 O (165.2 ± 0.7 kcal/mol), 73 indicating that H 2 O is a slightly weaker Lewis base than H 2 S. These results are consistent with the higher binding energies for the SO 3 •H 2 O/H 2 S complexes, as compared to the SO 2 •H 2 O/H 2 S complexes.…”

Section: E Nmentioning

confidence: 77%

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S

et al. 2019

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We have performed an extensive computational investigation of the potential energy surfaces for the reactions of SO x (x = 2 or 3) with H 2 S and H 2 O in the gas phase and in aqueous solution at the CCSD(T)/CBS level of theory plus a self-consistent reaction field approach. Formation of a gas-phase H 2 SO 4 from the hydrolysis of SO 3 at lower temperatures requires the presence of additional water molecules. When additional waters are introduced, the barrier for H 2 SO 4 formation is significantly reduced, and a barrierless transition occurs with only three excess waters as well as in aqueous solution. In a mixture of H 2 O, H 2 S, and SO 3 , formation of H 2 S 2 O 3 has a lower barrier in the gas phase than does the formation of H 2 SO 4 . In aqueous solution, no barrier is predicted, and both are likely to be formed. Introduction of an additional water to the SO 3 + H 2 S reaction results in a decrease in barrier height, nearly identical to the ∼18 kcal/mol catalytic effect of the first additional water in SO 3 hydrolysis, with the barrier for H 2 S 2 O 3 formation disappearing altogether in aqueous solution. Formation of H 2 SO 3 by the way of SO 2 hydrolysis is unlikely. Excess waters reduce the barrier for SO 2 hydrolysis; however, the overall endothermicity is increased as waters are added. The formation of H 2 S 2 O 2 from SO 2 and H 2 S via an isostructural pathway to SO 2 hydrolysis is unlikely, with additional water molecules resulting in a small increase in the overall endothermicity and a catalytic effect smaller than that observed for the SO 3 reactions. The results of this work have implications pertaining to the formation of H 2 SO 4 , H 2 S 2 O 3 , H 2 SO 3 , and H 2 S 2 O 2 in the atmospheres of Earth and Venus. These results also question the existence of H 2 S 2 O 2 as an intermediate in the Claus process.

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Section: E Nmentioning

confidence: 77%

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S

et al. 2019

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Completing the Redox‐Series of Silicon Trisdioxolene:ortho‐Quinone and Lewis Superacid Make a Powerful Redox Catalyst

Maskey

Bendel

Malzacher

et al. 2020

Chemistry A European J

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Quinones are mild oxidants, the redox potentials of which can be increasedb ys upramolecular interactions. Whereas this goal has been achieved by hydrogen bondingo rm olecular encapsulation, aL ewis acid-binding strategyf or redox amplificationo fq uinones is unexplored. Herein,t he redox chemistry of silicon tris(perchloro)dioxolene 1 was studied, whichi st he formal adduct of orthoperchloroquinone Q Cl with the Lewiss uperacid bis(perchlorocatecholato)silane 2.B yi solatingt he anionic monoradical 1C À À ,t he redox-series of ac entury-old class of compounds was completed. Cyclic voltammetry measurements revealed that the redox potentiali n1 was shifted by more than 1V into the anodic direction compared to Q Cl ,r eaching that of "magic blue" or NO + .I ta llowed oxidation of challenging substrates such as aromatic hydrocarbons and couldb ea pplieda sa ne fficient redox catalyst. Remarkably,t his powerful reagent formed in situ by combining the twoc ommercially available precursors SiI 4 and Q Cl .

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Rational Optimization of Lewis‐Acid Catalysts for the Direct Amination of Alcohols, Part 1 – Activity Descriptors for Metal Triflates and Triflimides

et al. 2020

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Herein we report a comparison of Lewis acidity indicators (affinity scales, electronegativity, Fukui functions, global electrophilicity index) with a new in silico Beckett–Childs descriptor based on the build‐up of partial charge, computed by DFT, on phosphine oxide coordinated to a Lewis acid. When applied to a broad series of triflate and triflimide salts, the last descriptor allowed a qualitative description of catalytic activity trends for the model amination reaction of benzyl alcohol with aniline. A high activity for titanium triflimide was predicted and experimentally confirmed.

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Formation Mechanism of NF₄⁺ Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids

Cited by 4 publications

References 55 publications

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S

Completing the Redox‐Series of Silicon Trisdioxolene:ortho‐Quinone and Lewis Superacid Make a Powerful Redox Catalyst

Rational Optimization of Lewis‐Acid Catalysts for the Direct Amination of Alcohols, Part 1 – Activity Descriptors for Metal Triflates and Triflimides

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Formation Mechanism of NF4+ Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids

Cited by 4 publications

References 55 publications

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SOx with H2O and H2S

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SOx with H2O and H2S

Completing the Redox‐Series of Silicon Trisdioxolene:ortho‐Quinone and Lewis Superacid Make a Powerful Redox Catalyst

Rational Optimization of Lewis‐Acid Catalysts for the Direct Amination of Alcohols, Part 1 – Activity Descriptors for Metal Triflates and Triflimides

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Product

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Formation Mechanism of NF₄⁺ Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO_x with H₂O and H₂S