Beyond the classical thermodynamic contributions to hydrogen atom abstraction reactivity

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F18%3A00495953" target="_blank" >RIV/61388955:_____/18:00495953 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1073/pnas.1806399115" target="_blank" >http://dx.doi.org/10.1073/pnas.1806399115</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1073/pnas.1806399115" target="_blank" >10.1073/pnas.1806399115</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Beyond the classical thermodynamic contributions to hydrogen atom abstraction reactivity

Popis výsledku v původním jazyce

Hydrogen atom abstraction (HAA) reactions are cornerstones of chemistry. Various (metallo)enzymes performing the HAA catalysis evolved in nature and inspired the rational development of multiple synthetic catalysts. Still, the factors determining their catalytic efficiency are not fully understood. Herein, we define the simple thermodynamic factor η by employing two thermodynamic cycles: one for an oxidant (catalyst), along with its reduced, protonated, and hydrogenated form, and one for the substrate, along with its oxidized, deprotonated, and dehydrogenated form. It is demonstrated that η reflects the propensity of the substrate and catalyst for (a)synchronicity in concerted H+/e- transfers. As such, it significantly contributes to the activation energies of the HAA reactions, in addition to a classical thermodynamic (Bell-Evans-Polanyi) effect. In an attempt to understand the physicochemical interpretation of η, we discovered an elegant link between η and reorganization energy λ from Marcus theory. We discovered computationally that for a homologous set of HAA reactions, λ reaches its maximum for the lowest |η|, which then corresponds to the most synchronous HAA mechanism. This immediately implies that among HAA processes with the same reaction free energy, ΔG0, the highest barrier (≡ΔG≠) is expected for the most synchronous proton-coupled electron (i.e., hydrogen) transfer. As proof of concept, redox and acidobasic properties of nonheme FeIVO complexes are correlated with activation free energies for HAA from C-H and O-H bonds. We believe that the reported findings may represent a powerful concept in designing new HAA catalysts.

Název v anglickém jazyce

Beyond the classical thermodynamic contributions to hydrogen atom abstraction reactivity

Popis výsledku anglicky

Hydrogen atom abstraction (HAA) reactions are cornerstones of chemistry. Various (metallo)enzymes performing the HAA catalysis evolved in nature and inspired the rational development of multiple synthetic catalysts. Still, the factors determining their catalytic efficiency are not fully understood. Herein, we define the simple thermodynamic factor η by employing two thermodynamic cycles: one for an oxidant (catalyst), along with its reduced, protonated, and hydrogenated form, and one for the substrate, along with its oxidized, deprotonated, and dehydrogenated form. It is demonstrated that η reflects the propensity of the substrate and catalyst for (a)synchronicity in concerted H+/e- transfers. As such, it significantly contributes to the activation energies of the HAA reactions, in addition to a classical thermodynamic (Bell-Evans-Polanyi) effect. In an attempt to understand the physicochemical interpretation of η, we discovered an elegant link between η and reorganization energy λ from Marcus theory. We discovered computationally that for a homologous set of HAA reactions, λ reaches its maximum for the lowest |η|, which then corresponds to the most synchronous HAA mechanism. This immediately implies that among HAA processes with the same reaction free energy, ΔG0, the highest barrier (≡ΔG≠) is expected for the most synchronous proton-coupled electron (i.e., hydrogen) transfer. As proof of concept, redox and acidobasic properties of nonheme FeIVO complexes are correlated with activation free energies for HAA from C-H and O-H bonds. We believe that the reported findings may represent a powerful concept in designing new HAA catalysts.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Proceedings of the National Academy of Science of the United Stated of America

ISSN

1091-6490

e-ISSN

—

Svazek periodika

115

Číslo periodika v rámci svazku

44

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

"E10287"-"E10294"

Kód UT WoS článku

000448713200001

EID výsledku v databázi Scopus

2-s2.0-85055636055