Excitation/detection energy controlled anisotropy dynamics in asymmetrically cyano substituted tri-podal molecules

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F20%3A39916360" target="_blank" >RIV/00216275:25310/20:39916360 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1039/D0CP01726D" target="_blank" >https://doi.org/10.1039/D0CP01726D</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d0cp01726d" target="_blank" >10.1039/d0cp01726d</a>

Result language

angličtina

Original language name

Excitation/detection energy controlled anisotropy dynamics in asymmetrically cyano substituted tri-podal molecules

Original language description

In the present work, the photophysical properties of two series of asymmetrical tri-podal molecules are studied, in order to determine the dependence of energy localization/delocalization phenomena on excitation and detection wavelength, by means of steady state, femtosecond time-resolved fluorescence and anisotropy spectroscopy. The molecules bear triphenylamine as an electron donating core and an acetylenic or olefinic pi-conjugated bridge. At the periphery, they are substituted by no, one, two or three -CN groups used as electron acceptors. Thus, the compounds with only one or two -CN groups are asymmetrically substituted. As a comparison, the photophysics of their dipolar and quadrupolar analogues is also presented. The steady state absorption spectra of the asymmetrical tri-podal compounds exhibit a broadening and a low energy shoulder due to the splitting of the excited states. The fluorescence spectra are more red-shifted in the tri-podal molecules with a single -CN group, providing the first evidence of its mostly dipolar nature. Time-resolved anisotropy measurements by using different excitation and detection wavelengths provide clear evidence that the asymmetrical tri-podal molecules with one or two -CN groups behave like octupolar molecules upon high-energy excitation (the initial anisotropy is found 0.1-0.15), while upon low-energy excitation they reveal a behavior expected for linear dipolar or V-shaped quadrupolar molecules (the initial anisotropy is very close to 0.4 and 0.17, respectively). The symmetrical tri-podal compounds with no or three cyano groups, exhibit an anisotropy depolarization time of 2.5 ps attributed to energy hopping. The amplitude of this energy hopping component is wavelength dependent and increases as the excitation is shifted towards the long wavelength edge.

Czech name

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Czech description

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Type

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

CEP classification

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OECD FORD branch

10401 - Organic chemistry

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

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

Name of the periodical

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

—

Volume of the periodical

22

Issue of the periodical within the volume

29

Country of publishing house

GB - UNITED KINGDOM

Number of pages

10

Pages from-to

16681-16690

UT code for WoS article

000556485900017

EID of the result in the Scopus database

2-s2.0-85088881717