The absorption spectrum of cis-azobenzene

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00095381" target="_blank" >RIV/00216224:14310/17:00095381 - isvavai.cz</a>

Výsledek na webu

<a href="http://pubs.rsc.org/en/content/articlelanding/2017/pp/c7pp00314e#!divAbstract" target="_blank" >http://pubs.rsc.org/en/content/articlelanding/2017/pp/c7pp00314e#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c7pp00314e" target="_blank" >10.1039/c7pp00314e</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The absorption spectrum of cis-azobenzene

Popis výsledku v původním jazyce

Azobenzene is a prototypical photochromic molecule existing in two isomeric forms, which has numerous photochemical applications that rely on a precise knowledge of the molar absorption coefficients (e). Careful analysis revealed that the previously reported absorption spectra of the "pure" isomers were in fact mutually contaminated by small amounts of the other isomer. Therefore, the absorption spectra of both trans- and cis-azobenzene in methanol were re-determined at temperatures of 5-45 degrees C. The thermodynamically more stable trans-azobenzene was prepared by warming the solution in the dark. To obtain the spectrum of cis-azobenzene three methods were used, which gave consistent results within the limits of error. The method based on the subtraction of derivative spectra coupled with a global analysis of the spectra recorded during thermal cis-trans isomerization is shown to give slightly more reliable results than the method using isomeric ratios determined by 1H-NMR. The described methods are readily generalizable to other azobenzene derivatives and to other photochromic systems. The practical implication of the re-determined e values is demonstrated by a very high precision of spectrophotometric species analysis in azobenzene isomeric mixtures. The new e values imply that the previously reported quantum yields must be revised.

Název v anglickém jazyce

The absorption spectrum of cis-azobenzene

Popis výsledku anglicky

Azobenzene is a prototypical photochromic molecule existing in two isomeric forms, which has numerous photochemical applications that rely on a precise knowledge of the molar absorption coefficients (e). Careful analysis revealed that the previously reported absorption spectra of the "pure" isomers were in fact mutually contaminated by small amounts of the other isomer. Therefore, the absorption spectra of both trans- and cis-azobenzene in methanol were re-determined at temperatures of 5-45 degrees C. The thermodynamically more stable trans-azobenzene was prepared by warming the solution in the dark. To obtain the spectrum of cis-azobenzene three methods were used, which gave consistent results within the limits of error. The method based on the subtraction of derivative spectra coupled with a global analysis of the spectra recorded during thermal cis-trans isomerization is shown to give slightly more reliable results than the method using isomeric ratios determined by 1H-NMR. The described methods are readily generalizable to other azobenzene derivatives and to other photochromic systems. The practical implication of the re-determined e values is demonstrated by a very high precision of spectrophotometric species analysis in azobenzene isomeric mixtures. The new e values imply that the previously reported quantum yields must be revised.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

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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)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

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

Název periodika

PHOTOCHEMICAL AND PHOTOBIOLOGICAL SCIENCES

ISSN

1474-905X

e-ISSN

—

Svazek periodika

16

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

1749-1756

Kód UT WoS článku

000417283600002

EID výsledku v databázi Scopus

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