Structural assignment of fluorocyclobutenes by 19f nmr spectroscopy – comparison of calculated 19f nmr shielding constants with experimental 19f nmr shifts

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F18%3A43917617" target="_blank" >RIV/60461373:22310/18:43917617 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1002/ejoc.201801119" target="_blank" >http://dx.doi.org/10.1002/ejoc.201801119</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/ejoc.201801119" target="_blank" >10.1002/ejoc.201801119</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Structural assignment of fluorocyclobutenes by 19f nmr spectroscopy – comparison of calculated 19f nmr shielding constants with experimental 19f nmr shifts

Popis výsledku v původním jazyce

Although the optimized reduction of perfluorocyclobutene with LiAlH4 gave a quantitative yield of the target 3,3,4,4-tetrafluorocyclobut-1-ene, unoptimized reductions led to complex inseparable mixtures of fluorocyclobutenes. These mixtures showed highly complex19F NMR spectra, the assignment of which was quite tedious. Hence, we accomplished a series of19F NMR magnetic shielding computations. Suprisingly, various DFT approaches, including both traditional and advanced functionals, gave highly diverse results with poor correlations between the experimental and computed19F chemical shifts, and the individual fluorocyclobutenes could not be identified. In contrast, the Hartree–Fock (HF) method gave shielding values which, although bearing some systematic error, enabled the assignment of all observed structures. Even better results were obtained by using a specially tailored IGLO-III basis set. The method developed was successfully employed for the assignment of the19F NMR shifts of unknown fluorocyclobutenes. © 2018 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Název v anglickém jazyce

Structural assignment of fluorocyclobutenes by 19f nmr spectroscopy – comparison of calculated 19f nmr shielding constants with experimental 19f nmr shifts

Popis výsledku anglicky

Although the optimized reduction of perfluorocyclobutene with LiAlH4 gave a quantitative yield of the target 3,3,4,4-tetrafluorocyclobut-1-ene, unoptimized reductions led to complex inseparable mixtures of fluorocyclobutenes. These mixtures showed highly complex19F NMR spectra, the assignment of which was quite tedious. Hence, we accomplished a series of19F NMR magnetic shielding computations. Suprisingly, various DFT approaches, including both traditional and advanced functionals, gave highly diverse results with poor correlations between the experimental and computed19F chemical shifts, and the individual fluorocyclobutenes could not be identified. In contrast, the Hartree–Fock (HF) method gave shielding values which, although bearing some systematic error, enabled the assignment of all observed structures. Even better results were obtained by using a specially tailored IGLO-III basis set. The method developed was successfully employed for the assignment of the19F NMR shifts of unknown fluorocyclobutenes. © 2018 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10401 - Organic chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

European Journal of Organic Chemistry

ISSN

1434-193X

e-ISSN

—

Svazek periodika

Neuveden

Číslo periodika v rámci svazku

srpen

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

3

Strana od-do

"3875–3877"

Kód UT WoS článku

000456391900002

EID výsledku v databázi Scopus

2-s2.0-85054742687