Conformational Behavior and Optical Properties of a Fluorophore Dimer as a Model of Luminescent Centers in Carbon Dots

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F20%3A00531407" target="_blank" >RIV/61388963:_____/20:00531407 - isvavai.cz</a>

Alternative codes found

RIV/61989592:15310/20:73604016

Result on the web

<a href="https://pubs.acs.org/doi/10.1021/acs.jpcc.0c02175" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.jpcc.0c02175</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcc.0c02175" target="_blank" >10.1021/acs.jpcc.0c02175</a>

Result language

angličtina

Original language name

Conformational Behavior and Optical Properties of a Fluorophore Dimer as a Model of Luminescent Centers in Carbon Dots

Original language description

The explanation of the origin of the fluorescence properties of carbon dots (CDs) represents an important task because of the great interest in the promising capabilities of these nanomaterials. 5-Oxo-1,2,3,5-tetrahydroimidazo-[1,2-α]-pyridine-7-carboxylic acid (IPCA), a molecular fluorophore, which is being created during the synthesis of CDs from citric acid and ethylenediamine, has been identified as an origin for the fluorescence of CDs. Using a combination of computational methods, we analyzed the UV absorption and fluorescence properties of the IPCA monomer and stacked IPCA dimers as basic models for the fluorescent centers in CDs. Density functional theory (DFT) for the ground state and time-dependent DFT calculations for excited states have been performed for the gas phase and for aqueous solution using a polarized continuum model. Classical molecular dynamics (MD) simulations of the dimer in the ground state have been carried out as well to investigate spontaneous association processes of IPCA and to analyze the ground state dynamics. Due to the complex charge distribution of the monomer and various possibilities of forming hydrogen bonds, in total, seven dimer structures have been identified at the DFT level as ground state minima with similar energies. Stabilities have been confirmed by domain-based local pair natural orbital (DLPNO) coupled cluster with singles and doubles and perturbative triples CCSD(T) calculations. The MD simulations confirm this picture, showing rotational flexibility processes of the two monomers with respect to each other. The lowest excited states have been characterized in terms of their orbital excitations and excitonic splitting. These calculations demonstrate the dominance of monomer π → π* transitions for the explanation of the observed UV spectra. Optimization of the dimer in the excited state did not lead to well-defined single structures but shows the picture of either intersection pathways to S1/S0 crossings which would quench fluorescence or stacked dimers with red-shifted fluorescence in comparison to the UV absorption. In the gas phase, both types of processes have been observed, whereas in solution only the stacked structures were found without any non-adiabatic radiationless deactivation processes.

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

10403 - Physical chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

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

Journal of Physical Chemistry C

ISSN

1932-7447

e-ISSN

—

Volume of the periodical

124

Issue of the periodical within the volume

26

Country of publishing house

US - UNITED STATES

Number of pages

11

Pages from-to

14327-14337

UT code for WoS article

000547455300029

EID of the result in the Scopus database

2-s2.0-85089905406