Observation of Long-Lived Charge-Separated States in Anthraquinone-Phenothiazine Electron Donor-Acceptor Dyads: Transient Optical and Electron Paramagnetic Resonance Spectroscopic Studies

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F23%3APU149139" target="_blank" >RIV/00216305:26620/23:PU149139 - isvavai.cz</a>

Result on the web

<a href="https://pubs.acs.org/doi/10.1021/acs.jpcb.3c02723" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.jpcb.3c02723</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcb.3c02723" target="_blank" >10.1021/acs.jpcb.3c02723</a>

Result language

angličtina

Original language name

Observation of Long-Lived Charge-Separated States in Anthraquinone-Phenothiazine Electron Donor-Acceptor Dyads: Transient Optical and Electron Paramagnetic Resonance Spectroscopic Studies

Original language description

We prepared a series of phenothiazine (PTZ)-anthraquinone(AQ) electron donor-acceptor dyads to study the relationshipbetween molecular structures and the possibility of charge transfer(CT) and intersystem crossing (ISC). As compared to the previouslyreported PTZ-AQ dyad with a direct connection of twounits via a C-N single bond, the PTZ and AQ units are connectedvia a p-phenylene or p-biphenylenelinker. Conformation restriction is imposed by attaching ortho-methyl groups on the phenylene linker. UV-vis absorptionspectra indicate electronic coupling between the PTZ and AQ unitsin the dyads without conformation restriction. Different from thepreviously reported PTZ-AQ, thermally activated delayedfluorescence (TADF) is observed for the dyads containing one phenylenelinker (PTZ-Ph-AQ and PTZ-PhMe-AQ). Theprompt fluorescence lifetime in cyclohexane is exceptionally long(& tau;(PF) = 62.0 ns, population ratio: 99.2%) and 245.0ns (93.5%) for PTZ-Ph-AQ and PTZ-PhMe-AQ, respectively (normally & tau;(PF) <20 ns); the delayedfluorescence lifetimes for these two dyads were determined as & tau;(DF) = 2.4 & mu;s (6.5%) and 7.6 & mu;s (0.8%), respectively.For the dyad containing a biphenylene linker (PTZ-Ph ( 2 ) Me-AQ), no TADF was observed. Charge-separated(CS) states were observed for PTZ-Ph-AQ and PTZ-PhMe-AQ, and the lifetimes were determined as 7.0 and 1.3 & mu;s, respectively,indicating the triplet spin multiplicity of the CS state. The (CS)-C-3 state lifetimes are shortened to 100 ns and 440 ns forthe two dyads, respectively, in the polar solvent acetonitrile. Fordyads with a longer linker, i.e., PTZ-Ph ( 2 ) Me-AQ, the CS state lifetime is not sensitiveto solvent polarity (& tau;(CS) = 1.8 and 1.3 & mu;s incyclohexane and acetonitrile, respectively). In reference dyads, wherethe PTZ unit is oxidized to sulfoxide, no CT absorption band and TADFwere observed, which is attributed to the increased CS state energy(>3 eV) becoming higher than that of the AQ triplet ((3)AQ*)stat

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10403 - Physical chemistry

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

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

Name of the periodical

JOURNAL OF PHYSICAL CHEMISTRY B

ISSN

1520-6106

e-ISSN

1520-5207

Volume of the periodical

127

Issue of the periodical within the volume

26

Country of publishing house

US - UNITED STATES

Number of pages

19

Pages from-to

5905-5923

UT code for WoS article

001018075300001

EID of the result in the Scopus database

2-s2.0-85164244685