Thermodynamic equilibrium between locally excited and charge-transfer states through thermally activated charge transfer in 1-(pyren-2'-yl)-o-carborane.
Chem Sci
; 13(18): 5205-5219, 2022 May 11.
Article
em En
| MEDLINE
| ID: mdl-35655553
ABSTRACT
Reversible conversion between excited-states plays an important role in many photophysical phenomena. Using 1-(pyren-2'-yl)-o-carborane as a model, we studied the photoinduced reversible charge-transfer (CT) process and the thermodynamic equilibrium between the locally-excited (LE) state and CT state, by combining steady state, time-resolved, and temperature-dependent fluorescence spectroscopy, fs- and ns-transient absorption, and DFT and LR-TDDFT calculations. Our results show that the energy gaps and energy barriers between the LE, CT, and a non-emissive 'mixed' state of 1-(pyren-2'-yl)-o-carborane are very small, and all three excited states are accessible at room temperature. The internal-conversion and reverse internal-conversion between LE and CT states are significantly faster than the radiative decay, and the two states have the same lifetimes and are in thermodynamic equilibrium.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article