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Bright Free-Radical Emission in Ionic Liquids |
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| Authors: | Wei Zheng Prof. XuPing Li Dr. Glib V. Baryshnikov Xueru Shan Dr. Farhan Siddique Dr. Cheng Qian Prof. Shengyin Zhao Prof. Hongwei Wu |
| Affiliation: | 1. State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Science and Technology of Eco-Textile, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620 China These authors contributed equally to this work.;2. College of Energy Materials and Chemistry, Inner Mongolia University, Hohhot, 010021 P. R. China;3. Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden;4. State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Science and Technology of Eco-Textile, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620 China;5. Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Bahauddin Zakariya University, Multan, 60800 Pakistan |
| Abstract: | It is challenging to achieve stable and efficient radical emissions under ambient conditions. Herein, we present a rational design strategy to protect photoinduced carbonyl free radical emission through electrostatic interaction and spin delocalization effects. The host-guest system is constructed from tricarbonyl-substituted benzene molecules and a series of imidazolium ionic liquids as the guest and host, respectively, whereby the carbonyl anion radical emission can be in situ generated under the light irradiation and further stabilized by electrostatic interaction. More importantly, the anion species and the alkyl chain length of imidazolium ionic liquids show a noticeable effect on luminescence efficiency, with the highest radical emission efficiency is as high as 53.3 % after optimizing the imidazole ionic liquid's structure, which is about four times higher than the polymer-protected radical system. Theoretical calculations confirm the synergistic effect of strong electrostatic interactions and that the spin delocalization effect significantly stabilizes the radical emission. Moreover, such a radical emission system also could be integrated with a fluorescent dye to induce multi-color or even white light emission with reversible temperature-responsive characteristics. The radical emission system can also be used to detect different amine compounds on the basis of the emission changes and photoactivation time. |
| Keywords: | Detection Electrostatic Interaction Multi-Color Emission Radical Emission Spin Delocalization |