4-OH coumarin based rotary switches: Tautomeric state and effect of the stator

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26310%2F21%3APU141894" target="_blank" >RIV/00216305:26310/21:PU141894 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0143720820315588?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0143720820315588?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.dyepig.2020.108861" target="_blank" >10.1016/j.dyepig.2020.108861</a>

Jazyk výsledku

angličtina

Název v původním jazyce

4-OH coumarin based rotary switches: Tautomeric state and effect of the stator

Popis výsledku v původním jazyce

Two new 4-OH coumarin based rotary switches, containing fixed carbonyl groups in the rotor, have been synthesized and their properties have been studied by combined use of DFT calculations and molecular spectroscopy (UV-Vis absorbance and emission, NMR). It was found that the structure of the stator (naphthyl in 2 or quinolyl moiety in 3) and solvents polarity do not influence their azo-hydrazone tautomerism. Both compounds exist as keto (hydrazone) tautomers. The NMR data indicate a mixture of E (major) and Z (minor) keto form isomers in solution. The results are in very good agreement with ground state DFT calculations. The keto tautomers exhibit different emission behavior depending on the structure of the stators. Comparing to 2, more intensive emission and higher lifetime was observed in 3, where the formation of intramolecular hydrogen bonding of the hydrazone NH with the N atom of quinoline restricts the rotation of the stator. According to the spectral data and the TDDFT analysis the observed emission originates from the excitation of the keto tautomers and does not include excited state proton transfer. It was shown that the protonation is a suitable stimulus for E/Z switching in 2, where a possible mechanism is sketched. In the case of 3, the addition of acid leads to the pmtonation of the quinolyl nitrogen atom, which slightly affects the E/Z isomerization ratio.

Název v anglickém jazyce

4-OH coumarin based rotary switches: Tautomeric state and effect of the stator

Popis výsledku anglicky

Two new 4-OH coumarin based rotary switches, containing fixed carbonyl groups in the rotor, have been synthesized and their properties have been studied by combined use of DFT calculations and molecular spectroscopy (UV-Vis absorbance and emission, NMR). It was found that the structure of the stator (naphthyl in 2 or quinolyl moiety in 3) and solvents polarity do not influence their azo-hydrazone tautomerism. Both compounds exist as keto (hydrazone) tautomers. The NMR data indicate a mixture of E (major) and Z (minor) keto form isomers in solution. The results are in very good agreement with ground state DFT calculations. The keto tautomers exhibit different emission behavior depending on the structure of the stators. Comparing to 2, more intensive emission and higher lifetime was observed in 3, where the formation of intramolecular hydrogen bonding of the hydrazone NH with the N atom of quinoline restricts the rotation of the stator. According to the spectral data and the TDDFT analysis the observed emission originates from the excitation of the keto tautomers and does not include excited state proton transfer. It was shown that the protonation is a suitable stimulus for E/Z switching in 2, where a possible mechanism is sketched. In the case of 3, the addition of acid leads to the pmtonation of the quinolyl nitrogen atom, which slightly affects the E/Z isomerization ratio.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA17-21105S" target="_blank" >GA17-21105S: Materiály s multiFOtonovou absoRpcí pro 3D tisk a 3D zobrazování (M-FOR-3D)</a><br>

Návaznosti

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

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

DYES AND PIGMENTS

ISSN

0143-7208

e-ISSN

1873-3743

Svazek periodika

184

Číslo periodika v rámci svazku

108861

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

1-12

Kód UT WoS článku

000580897700102

EID výsledku v databázi Scopus

2-s2.0-85091665153