Free Radical Isomerizations in Acetylene Bromoboration Reaction

J 2021

Free Radical Isomerizations in Acetylene Bromoboration Reaction

SEMRÁD, Hugo, Ctibor MAZAL a Markéta MUNZAROVÁ

Základní údaje

Originální název

Free Radical Isomerizations in Acetylene Bromoboration Reaction

Autoři

SEMRÁD, Hugo (203 Česká republika, domácí), Ctibor MAZAL (203 Česká republika, domácí) a Markéta MUNZAROVÁ (203 Česká republika, garant, domácí)

Vydání

Molecules, MDPI, 2021, 1420-3049

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10401 Organic chemistry

Stát vydavatele

Švýcarsko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 4.927

Kód RIV

RIV/00216224:14310/21:00121467

Organizační jednotka

Přírodovědecká fakulta

DOI

http://dx.doi.org/10.3390/molecules26092501

UT WoS

000650680000001

Klíčová slova anglicky

free radicals; isomerization; acetylene; bromoboration; mechanism; addition-elimination; DFT; MP2

Štítky

rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 28. 5. 2021 11:20, Mgr. Marie Šípková, DiS.

Anotace

V originále

The experimentally motivated question of the acetylene bromoboration mechanism was addressed in order to suggest possible radical isomerization pathways for the syn-adduct. Addition–elimination mechanisms starting with a bromine radical attack at the “bromine end” or the “boron end” of the C=C bond were considered. Dispersion-corrected DFT and MP2 methods with the SMD solvation model were employed using three all-electron bases as well as the ECP28MWB ansatz. The rate-determining, elimination step had a higher activation energy (12 kcal mol−1) in case of the “bromine end” attack due to intermediate stabilization at both the MP2 and DFT levels. In case of the “boron end” attack, two modes of C–C bond rotation were followed and striking differences in MP2 vs. DFT potential energy surfaces were observed. Employing MP2, addition was followed by either a 180° rotation through an eclipsed conformation of vicinal bromine atoms or by an opposite rotation avoiding that conformation, with 5 kcal mol−1 of elimination activation energy. Within B3LYP, the addition and rotation proceeded simultaneously, with a 9 (7) kcal mol−1 barrier for rotation involving (avoiding) eclipsed conformation of vicinal bromines. For weakly bound complexes, ZPE corrections with MP2 revealed significant artifacts when diffuse bases were included, which must be considered in the Gibbs free energy profile interpretation.

Návaznosti

LM2015047, projekt VaV

Název: Česká národní infrastruktura pro biologická data (Akronym: ELIXIR-CZ)

Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, Česká národní infrastruktura pro biologická data

LM2018140, projekt VaV

Název: e-Infrastruktura CZ (Akronym: e-INFRA CZ)

Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, e-Infrastruktura CZ

Citovat

SEMRÁD, Hugo, Ctibor MAZAL a Markéta MUNZAROVÁ. Free Radical Isomerizations in Acetylene Bromoboration Reaction. Molecules. MDPI, 2021, roč. 26, č. 9, s. "2501", 15 s. ISSN 1420-3049. Dostupné z: https://dx.doi.org/10.3390/molecules26092501.

@article{1763256,
   author = {Semrád, Hugo and Mazal, Ctibor and Munzarová, Markéta},
   article_number = {9},
   doi = {http://dx.doi.org/10.3390/molecules26092501},
   keywords = {free radicals; isomerization; acetylene; bromoboration; mechanism; addition-elimination; DFT; MP2},
   language = {eng},
   issn = {1420-3049},
   journal = {Molecules},
   title = {Free Radical Isomerizations in Acetylene Bromoboration Reaction},
   url = {https://doi.org/10.3390/molecules26092501},
   volume = {26},
   year = {2021}
}

TY  - JOUR
ID  - 1763256
AU  - Semrád, Hugo - Mazal, Ctibor - Munzarová, Markéta
PY  - 2021
TI  - Free Radical Isomerizations in Acetylene Bromoboration Reaction
JF  - Molecules
VL  - 26
IS  - 9
SP  - "2501"
EP  - "2501"
PB  - MDPI
SN  - 14203049
KW  - free radicals
KW  - isomerization
KW  - acetylene
KW  - bromoboration
KW  - mechanism
KW  - addition-elimination
KW  - DFT
KW  - MP2
UR  - https://doi.org/10.3390/molecules26092501
N2  - The experimentally motivated question of the acetylene bromoboration mechanism was addressed in order to suggest possible radical isomerization pathways for the syn-adduct. Addition–elimination mechanisms starting with a bromine radical attack at the “bromine end” or the “boron end” of the C=C bond were considered. Dispersion-corrected DFT and MP2 methods with the SMD solvation model were employed using three all-electron bases as well as the ECP28MWB ansatz. The rate-determining, elimination step had a higher activation energy (12 kcal mol−1) in case of the “bromine end” attack due to intermediate stabilization at both the MP2 and DFT levels. In case of the “boron end” attack, two modes of C–C bond rotation were followed and striking differences in MP2 vs. DFT potential energy surfaces were observed. Employing MP2, addition was followed by either a 180° rotation through an eclipsed conformation of vicinal bromine atoms or by an opposite rotation avoiding that conformation, with 5 kcal mol−1 of elimination activation energy. Within B3LYP, the addition and rotation proceeded simultaneously, with a 9 (7) kcal mol−1 barrier for rotation involving (avoiding) eclipsed conformation of vicinal bromines. For weakly bound complexes, ZPE corrections with MP2 revealed significant artifacts when diffuse bases were included, which must be considered in the Gibbs free energy profile interpretation.
ER  -

SEMRÁD, Hugo, Ctibor MAZAL a Markéta MUNZAROVÁ. Free Radical Isomerizations in Acetylene Bromoboration Reaction. \textit{Molecules}. MDPI, 2021, roč.~26, č.~9, s.~''2501'', 15 s. ISSN~1420-3049. Dostupné z: https://dx.doi.org/10.3390/molecules26092501.

Podrobný výpis o publikaci