Role of Equilibrium Associations on the Hydrogen Atom Transfer from the Triethylborane–Methanol Complex

2013 ◽  
Vol 78 (4) ◽  
pp. 1553-1558 ◽  
Author(s):  
Guillaume Povie ◽  
Mattia Marzorati ◽  
Peter Bigler ◽  
Philippe Renaud
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer

Hydrogen atom transfer from 1,2- and 1,3-diols to the cumyloxyl radical. The role of structural effects on metal-ion induced C–H bond deactivation

2019 ◽  
Vol 55 (36) ◽  
pp. 5227-5230 ◽  
Author(s):  
Teo Martin ◽  
Michela Salamone ◽  
Massimo Bietti
Keyword(s):  
Hydrogen Atom ◽  
Metal Ion ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Structural Effects ◽  
Substrate Structure

Strong C–H bond deactivation toward HAT has been observed in the reactions of the cumyloxyl radical with 1,2- and 1,3-diols, following addition of Li+ and Ca2+. Weaker effects have been observed with Mg2+. The role of substrate structure and of the metal ion is discussed.

On the Role of Hydrogen Atom Transfer (HAT) in Thermal Activation of Methane by MnO+: Entropy vs. Energy

2019 ◽  
Vol 233 (6) ◽  
pp. 771-783 ◽  
Author(s):  
Brendan C. Sweeny ◽  
Hanqing Pan ◽  
Shaun G. Ard ◽  
Nicholas S. Shuman ◽  
Albert A. Viggiano
Keyword(s):  
Hydrogen Atom ◽  
Transition State ◽  
Branching Fractions ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Temperature Dependent ◽  
Proton Coupled Electron Transfer ◽  
Selected Ion Flow Tube ◽  
Increasing Temperature

Abstract The temperature dependent kinetics and product branching fractions of first-row transition metal oxide cation MnO+ with CH4 and CD4 at temperatures between 200 and 600 K are measured using a selected-ion flow tube apparatus. Likely reaction mechanisms are determined by comparison of temperature dependent kinetics to statistical modeling along calculated reaction coordinates. The data is well-modeled with the reaction proceeding over a rate limiting four-centered transition state leading to an insertion intermediate, similar to reactions of NiO+ and FeO+, and showing characteristics of proton-coupled electron transfer (PCET). However, a more direct pathway traversing a transition state of hydrogen atom transfer (HAT) character to a hydroxyl intermediate is found to possibly be competitive, especially with increasing temperature. While uncertainties in calculated energetics limit quantitative assessment of the role of HAT at thermal energies, it is clear that this mechanism becomes increasingly prevalent in higher energy regimes.

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