Ab initio conformational analysis of 1,2,3,4- tetrahydroquinoline and the high-resolution rotational spectrum of its lowest energy conformer

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F18%3A43915516" target="_blank" >RIV/60461373:22340/18:43915516 - isvavai.cz</a>

Výsledek na webu

<a href="http://pubs.rsc.org/en/content/articlehtml/2018/cp/c8cp00953h" target="_blank" >http://pubs.rsc.org/en/content/articlehtml/2018/cp/c8cp00953h</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c8cp00953h" target="_blank" >10.1039/c8cp00953h</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ab initio conformational analysis of 1,2,3,4- tetrahydroquinoline and the high-resolution rotational spectrum of its lowest energy conformer

Popis výsledku v původním jazyce

The saturated part of the 1,2,3,4-tetrahydroquinoline (THQ) molecule allows for the possibility of multiple conformers&apos; existence. High-resolution microwave spectroscopy, supported by high-level quantum chemistry calculations, was used to determine the precise molecular structures of the conformers of THQ. Via the MP2 calculations, we were able to discriminate four stable conformations, i.e. two pairs of energetically equivalent enantiomorphic conformers. The results of the calculations also indicate that energetically non-equivalent conformers are separated by a low energy barrier (104 cm−1) that allows for conformational cooling to occur. The high resolution rotational spectrum with resolved hyperfine structure in the frequency range of 7–20 GHz was obtained using both the In-phase/quadrature-phase-Modulation Passage-Acquired-Coherence Technique (IMPACT) and the coaxially oriented beam resonator arrangement (COBRA) to perform Fourier transform microwave (FTMW) spectroscopy. The precise values of the rotational constants, 14N nuclear hyperfine coupling parameters and centrifugal distortion parameters were determined from the measured transition frequencies. Based on our experimental results, only the most stable enantiomeric pair of THQ contributes to the rotational spectrum under the conditions of our experiment as the less stable conformers seem to efficiently relax to the lower energy conformers. Thus the experimentally evaluated molecular constants unambiguously define the lowest energy conformer of 1,2,3,4-tetrahydroquinoline.

Název v anglickém jazyce

Ab initio conformational analysis of 1,2,3,4- tetrahydroquinoline and the high-resolution rotational spectrum of its lowest energy conformer

Popis výsledku anglicky

The saturated part of the 1,2,3,4-tetrahydroquinoline (THQ) molecule allows for the possibility of multiple conformers&apos; existence. High-resolution microwave spectroscopy, supported by high-level quantum chemistry calculations, was used to determine the precise molecular structures of the conformers of THQ. Via the MP2 calculations, we were able to discriminate four stable conformations, i.e. two pairs of energetically equivalent enantiomorphic conformers. The results of the calculations also indicate that energetically non-equivalent conformers are separated by a low energy barrier (104 cm−1) that allows for conformational cooling to occur. The high resolution rotational spectrum with resolved hyperfine structure in the frequency range of 7–20 GHz was obtained using both the In-phase/quadrature-phase-Modulation Passage-Acquired-Coherence Technique (IMPACT) and the coaxially oriented beam resonator arrangement (COBRA) to perform Fourier transform microwave (FTMW) spectroscopy. The precise values of the rotational constants, 14N nuclear hyperfine coupling parameters and centrifugal distortion parameters were determined from the measured transition frequencies. Based on our experimental results, only the most stable enantiomeric pair of THQ contributes to the rotational spectrum under the conditions of our experiment as the less stable conformers seem to efficiently relax to the lower energy conformers. Thus the experimentally evaluated molecular constants unambiguously define the lowest energy conformer of 1,2,3,4-tetrahydroquinoline.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10406 - Analytical chemistry

Projekt

<a href="/cs/project/GA18-08667S" target="_blank" >GA18-08667S: Slabé interakce v terahertzové spektroskopii</a><br>

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

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

—

Svazek periodika

20

Číslo periodika v rámci svazku

21

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

7

Strana od-do

14664-14670

Kód UT WoS článku

000434246300037

EID výsledku v databázi Scopus

2-s2.0-85048001938