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Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation

Achieving organic room-temperature phosphorescence (RTP) in a solvent-free liquid state is a challenging task because the liquid state provides a less rigid environment than the crystal. Here, we report that an unsymmetrical heteroaromatic 1,2-diketone forms an organic RTP liquid. This diketone exis...

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Detalles Bibliográficos
Autores principales: Komura, Mao, Ogawa, Takuji, Tani, Yosuke
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8580009/
https://www.ncbi.nlm.nih.gov/pubmed/34880986
http://dx.doi.org/10.1039/d1sc03800a
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author Komura, Mao
Ogawa, Takuji
Tani, Yosuke
author_facet Komura, Mao
Ogawa, Takuji
Tani, Yosuke
author_sort Komura, Mao
collection PubMed
description Achieving organic room-temperature phosphorescence (RTP) in a solvent-free liquid state is a challenging task because the liquid state provides a less rigid environment than the crystal. Here, we report that an unsymmetrical heteroaromatic 1,2-diketone forms an organic RTP liquid. This diketone exists as a kinetically stable supercooled liquid, which resists crystallisation even under pricking or shearing stresses, and remains as a liquid for several months. The unsymmetrical diketone core is flexible, with eight distinct conformers possible, which prevents nucleation and growth for the liquid–solid transition. Interestingly, the thermodynamically stable crystalline solid-state was non-emissive. Thus, the RTP of the diketone was found to be liquiefaction-induced. Single-crystal X-ray structure analysis revealed that the diminished RTP of the crystal is due to insufficient intermolecular interactions and restricted access to an emissive conformer. Our work demonstrates that flexible unsymmetrical skeletons are promising motifs for bistable liquid–solid molecular systems, which are useful for the further development of stimuli-responsive materials that use phase transitions.
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spelling pubmed-85800092021-12-07 Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation Komura, Mao Ogawa, Takuji Tani, Yosuke Chem Sci Chemistry Achieving organic room-temperature phosphorescence (RTP) in a solvent-free liquid state is a challenging task because the liquid state provides a less rigid environment than the crystal. Here, we report that an unsymmetrical heteroaromatic 1,2-diketone forms an organic RTP liquid. This diketone exists as a kinetically stable supercooled liquid, which resists crystallisation even under pricking or shearing stresses, and remains as a liquid for several months. The unsymmetrical diketone core is flexible, with eight distinct conformers possible, which prevents nucleation and growth for the liquid–solid transition. Interestingly, the thermodynamically stable crystalline solid-state was non-emissive. Thus, the RTP of the diketone was found to be liquiefaction-induced. Single-crystal X-ray structure analysis revealed that the diminished RTP of the crystal is due to insufficient intermolecular interactions and restricted access to an emissive conformer. Our work demonstrates that flexible unsymmetrical skeletons are promising motifs for bistable liquid–solid molecular systems, which are useful for the further development of stimuli-responsive materials that use phase transitions. The Royal Society of Chemistry 2021-09-10 /pmc/articles/PMC8580009/ /pubmed/34880986 http://dx.doi.org/10.1039/d1sc03800a Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Komura, Mao
Ogawa, Takuji
Tani, Yosuke
Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title_full Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title_fullStr Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title_full_unstemmed Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title_short Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
title_sort room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8580009/
https://www.ncbi.nlm.nih.gov/pubmed/34880986
http://dx.doi.org/10.1039/d1sc03800a
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