Endowing nitro-compounds with bright and stimuli-responsive luminescence based on propeller-like AIEgens
An electron-rich nitro group, having higher sensitivity to various environments, is attractive for constructing stimuli-responsive luminescent materials. However, it also causes the fluorescence quenching of luminogens, making a formidable challenge to achieving intense luminescence in nitro-compoun...
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Published in | Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 9; no. 36; pp. 12177 - 12183 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
28.09.2021
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Subjects | |
Online Access | Get full text |
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Summary: | An electron-rich nitro group, having higher sensitivity to various environments, is attractive for constructing stimuli-responsive luminescent materials. However, it also causes the fluorescence quenching of luminogens, making a formidable challenge to achieving intense luminescence in nitro-compounds. Herein, we design a group of bright nitro-compounds with high fluorescence efficiency, long-wavelength emission and multi-stimuli-responsive behaviors by combining through-space conjugated AIEgens and nitro groups. Two bright nitro-compounds were constructed by introducing a propeller-like skeleton with the π-conjugated rings, showing a strong intramolecular spatial delocalization of π-electrons. This character not only stabilizes the (π, π*) states to enable their energy below the n → π* transitions caused by the nitro groups, enormously hindering the intersystem crossing process and promoting radiative transition, but also provides a strong steric hindrance of aromatic rings to vastly restrict the nonradiative decay of the singlet excitons, thereby enabling a high fluorescence efficiency, up to 95%. Moreover, the propeller-like chromophore and the nitro group with strong electron-withdrawing capacity work in synergy to induce an environmentally responsive conversion of local excitation and charge transfer states, endowing these nitro-compounds with stimuli-responsive luminescence, including solvatochromism, thermochromism, and mechanochromism in a reversible way, which varies from green to red. These findings outline a fundamental principle for the construction of bright nitro-compounds with stimuli-responsive behaviors, endowing traditional nitro-compounds with new features for potential applications.
An electron-rich nitro group, having higher sensitivity to various environments, is attractive for constructing stimuli-responsive luminescent materials. |
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Bibliography: | Electronic supplementary information (ESI) available. CCDC 10.1039/d1tc01713f For ESI and crystallographic data in CIF or other electronic format see DOI 1969990 |
ISSN: | 2050-7526 2050-7534 |
DOI: | 10.1039/d1tc01713f |