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Excited-State Decay Paths in Tetraphenylethene Derivatives

[Image: see text] The photophysical properties of tetraphenylethene (TPE) compounds may differ widely depending on the substitution pattern, for example, with regard to the fluorescence quantum yield ϕ(f) and the propensity to exhibit aggregation-induced emission (AIE). We report combined electronic...

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Autores principales: Gao, Yuan-Jun, Chang, Xue-Ping, Liu, Xiang-Yang, Li, Quan-Song, Cui, Ganglong, Thiel, Walter
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385518/
https://www.ncbi.nlm.nih.gov/pubmed/28318255
http://dx.doi.org/10.1021/acs.jpca.7b00197
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author Gao, Yuan-Jun
Chang, Xue-Ping
Liu, Xiang-Yang
Li, Quan-Song
Cui, Ganglong
Thiel, Walter
author_facet Gao, Yuan-Jun
Chang, Xue-Ping
Liu, Xiang-Yang
Li, Quan-Song
Cui, Ganglong
Thiel, Walter
author_sort Gao, Yuan-Jun
collection PubMed
description [Image: see text] The photophysical properties of tetraphenylethene (TPE) compounds may differ widely depending on the substitution pattern, for example, with regard to the fluorescence quantum yield ϕ(f) and the propensity to exhibit aggregation-induced emission (AIE). We report combined electronic structure calculations and nonadiabatic dynamics simulations to study the excited-state decay mechanisms of two TPE derivatives with four methyl substituents, either in the meta position (TPE-4mM, ϕ(f) = 0.1%) or in the ortho position (TPE-4oM, ϕ(f) = 64.3%). In both cases, two excited-state decay pathways may be relevant, namely, photoisomerization around the central ethylenic double bond and photocyclization involving two adjacent phenyl rings. In TPE-4mM, the barrierless S(1) cyclization is favored; it is responsible for the ultralow fluorescence quantum yield observed experimentally. In TPE-4oM, both the S(1) photocyclization and photoisomerization paths are blocked by non-negligible barriers, and fluorescence is thus feasible. Nonadiabatic dynamics simulations with more than 1000 surface hopping trajectories show ultrafast cyclization upon photoexcitation of TPE-4mM, whereas TPE-4oM remains unreactive during the 1 ps simulations. We discuss the chances for spectroscopic detection of the postulated cyclic photoproduct of TPE-4mM and the relevance of our findings for the AIE process.
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spelling pubmed-53855182017-04-11 Excited-State Decay Paths in Tetraphenylethene Derivatives Gao, Yuan-Jun Chang, Xue-Ping Liu, Xiang-Yang Li, Quan-Song Cui, Ganglong Thiel, Walter J Phys Chem A [Image: see text] The photophysical properties of tetraphenylethene (TPE) compounds may differ widely depending on the substitution pattern, for example, with regard to the fluorescence quantum yield ϕ(f) and the propensity to exhibit aggregation-induced emission (AIE). We report combined electronic structure calculations and nonadiabatic dynamics simulations to study the excited-state decay mechanisms of two TPE derivatives with four methyl substituents, either in the meta position (TPE-4mM, ϕ(f) = 0.1%) or in the ortho position (TPE-4oM, ϕ(f) = 64.3%). In both cases, two excited-state decay pathways may be relevant, namely, photoisomerization around the central ethylenic double bond and photocyclization involving two adjacent phenyl rings. In TPE-4mM, the barrierless S(1) cyclization is favored; it is responsible for the ultralow fluorescence quantum yield observed experimentally. In TPE-4oM, both the S(1) photocyclization and photoisomerization paths are blocked by non-negligible barriers, and fluorescence is thus feasible. Nonadiabatic dynamics simulations with more than 1000 surface hopping trajectories show ultrafast cyclization upon photoexcitation of TPE-4mM, whereas TPE-4oM remains unreactive during the 1 ps simulations. We discuss the chances for spectroscopic detection of the postulated cyclic photoproduct of TPE-4mM and the relevance of our findings for the AIE process. American Chemical Society 2017-03-20 2017-04-06 /pmc/articles/PMC5385518/ /pubmed/28318255 http://dx.doi.org/10.1021/acs.jpca.7b00197 Text en Copyright © 2017 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Gao, Yuan-Jun
Chang, Xue-Ping
Liu, Xiang-Yang
Li, Quan-Song
Cui, Ganglong
Thiel, Walter
Excited-State Decay Paths in Tetraphenylethene Derivatives
title Excited-State Decay Paths in Tetraphenylethene Derivatives
title_full Excited-State Decay Paths in Tetraphenylethene Derivatives
title_fullStr Excited-State Decay Paths in Tetraphenylethene Derivatives
title_full_unstemmed Excited-State Decay Paths in Tetraphenylethene Derivatives
title_short Excited-State Decay Paths in Tetraphenylethene Derivatives
title_sort excited-state decay paths in tetraphenylethene derivatives
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385518/
https://www.ncbi.nlm.nih.gov/pubmed/28318255
http://dx.doi.org/10.1021/acs.jpca.7b00197
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