The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand
We describe here a new design strategy for obtaining boron complexes with aggregation- and crystallization-induced emission (AIE and CIE, respectively) properties based on the introduction of skeletal distortion. According to our recent results, despite the fact that an almost planar structure and r...
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MDPI AG
2020-07-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/7/615 |
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| author | Shunsuke Ohtani Masayuki Gon Kazuo Tanaka Yoshiki Chujo |
| author_facet | Shunsuke Ohtani Masayuki Gon Kazuo Tanaka Yoshiki Chujo |
| author_sort | Shunsuke Ohtani |
| collection | DOAJ |
| description | We describe here a new design strategy for obtaining boron complexes with aggregation- and crystallization-induced emission (AIE and CIE, respectively) properties based on the introduction of skeletal distortion. According to our recent results, despite the fact that an almost planar structure and robust conjugation were obtained, the boron azomethine complex provided a slight emission in solution and an enhanced emission in aggregation and crystal. Quantum calculation results propose that unexpected emission annihilation in solution could be caused through intramolecular bending in the excited state. Herein, to realize this unique molecular motion and obtain AIE and CIE molecules, the phenyl quinoline-based boron complexes <b>BPhQ</b> and <b>BPhQm</b> with distorted and planar structures were designed and synthesized, respectively. <b>BPhQm</b> showed emission in solution and aggregation-caused quenching (ACQ, <b>BPhQm</b>: <i>Φ</i><sub>F,sol.</sub> = 0.21, <i>Φ</i><sub>F,agg.</sub> = 0.072, <i>Φ</i><sub>F,cryst.</sub> = 0.051), while <b>BPhQ</b> exhibited a typical AIE and CIE (<b>BPhQ</b>: <i>Φ</i><sub>F,sol.</sub> = 0.008, <i>Φ</i><sub>F,agg.</sub> = 0.014, <i>Φ</i><sub>F,cryst.</sub> = 0.017). The optical data suggest that a large degree of molecular motion should occur in <b>BPhQ</b> after photo-excitation because of the intrinsic skeletal distortion. Furthermore, single-crystal X-ray diffraction data indicate that the distorted π-conjugated system plays a positive role in presenting solid-state emission by inhibiting consecutive π–π interactions. We demonstrate in this paper that the introduction of the distorted structure by boron complexation should be a new strategy for realizing AIE and CIE properties. |
| first_indexed | 2024-03-10T18:28:25Z |
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| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T18:28:25Z |
| publishDate | 2020-07-01 |
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| record_format | Article |
| series | Crystals |
| spelling | doaj.art-34bed4ea97d54543bb9bacce7b57cacf2023-11-20T06:48:10ZengMDPI AGCrystals2073-43522020-07-0110761510.3390/cryst10070615The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate LigandShunsuke Ohtani0Masayuki Gon1Kazuo Tanaka2Yoshiki Chujo3Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, JapanDepartment of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, JapanDepartment of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, JapanDepartment of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, JapanWe describe here a new design strategy for obtaining boron complexes with aggregation- and crystallization-induced emission (AIE and CIE, respectively) properties based on the introduction of skeletal distortion. According to our recent results, despite the fact that an almost planar structure and robust conjugation were obtained, the boron azomethine complex provided a slight emission in solution and an enhanced emission in aggregation and crystal. Quantum calculation results propose that unexpected emission annihilation in solution could be caused through intramolecular bending in the excited state. Herein, to realize this unique molecular motion and obtain AIE and CIE molecules, the phenyl quinoline-based boron complexes <b>BPhQ</b> and <b>BPhQm</b> with distorted and planar structures were designed and synthesized, respectively. <b>BPhQm</b> showed emission in solution and aggregation-caused quenching (ACQ, <b>BPhQm</b>: <i>Φ</i><sub>F,sol.</sub> = 0.21, <i>Φ</i><sub>F,agg.</sub> = 0.072, <i>Φ</i><sub>F,cryst.</sub> = 0.051), while <b>BPhQ</b> exhibited a typical AIE and CIE (<b>BPhQ</b>: <i>Φ</i><sub>F,sol.</sub> = 0.008, <i>Φ</i><sub>F,agg.</sub> = 0.014, <i>Φ</i><sub>F,cryst.</sub> = 0.017). The optical data suggest that a large degree of molecular motion should occur in <b>BPhQ</b> after photo-excitation because of the intrinsic skeletal distortion. Furthermore, single-crystal X-ray diffraction data indicate that the distorted π-conjugated system plays a positive role in presenting solid-state emission by inhibiting consecutive π–π interactions. We demonstrate in this paper that the introduction of the distorted structure by boron complexation should be a new strategy for realizing AIE and CIE properties.https://www.mdpi.com/2073-4352/10/7/615quinolineboron complexsolid-state emissionaggregation-induced emission |
| spellingShingle | Shunsuke Ohtani Masayuki Gon Kazuo Tanaka Yoshiki Chujo The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand Crystals quinoline boron complex solid-state emission aggregation-induced emission |
| title | The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand |
| title_full | The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand |
| title_fullStr | The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand |
| title_full_unstemmed | The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand |
| title_short | The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand |
| title_sort | design strategy for an aggregation and crystallization induced emission active molecule based on the introduction of skeletal distortion by boron complexation with a tridentate ligand |
| topic | quinoline boron complex solid-state emission aggregation-induced emission |
| url | https://www.mdpi.com/2073-4352/10/7/615 |
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