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High solid-state luminescence in propeller-shaped AIE-active pyridine-ketoiminate-boron complexes
Yanping Wu1, Zhenyu Li, Qingsong Liu
1Institute of Functional Organic Molecules and Materials, School of Chemistry and Chemical Engineering, Liaocheng University, No. 1 Hunan Road, Liaocheng, 252000, People's Republic of China. chliuzp@163.com wangxiaoqing@lcu.edu.cn.
Organic & Biomolecular Chemistry
|April 24, 2015
Summary
New organoboron complexes (2 and 3) exhibit enhanced fluorescence in high-viscosity solvents and solid states due to restricted molecular rotation. These compounds show potential as advanced aggregation-induced emission luminophores.
Area of Science:
- Materials Science
- Organic Chemistry
- Supramolecular Chemistry
Background:
- Organoboron complexes are known for their diverse applications in chemistry and materials science.
- Intramolecular rotation in low-viscosity environments often quenches luminescence in organic molecules.
- Aggregation-induced emission (AIE) is a phenomenon where luminescence is enhanced upon molecular aggregation.
Purpose of the Study:
- To develop novel pyridine-ketoiminate-based organoboron complexes.
- To investigate the photophysical properties of these complexes, particularly their emission behavior in different environments.
- To explore their potential as AIE luminophores for fluorescence imaging and materials science.
Main Methods:
- Synthesis of two pyridine-ketoiminate-based organoboron complexes (compounds 2 and 3).
- Photophysical characterization, including emission spectroscopy in solvents of varying viscosity.
- Solid-state emission studies and molecular aggregation experiments.
- X-ray crystallographic analysis to understand intermolecular interactions.
Main Results:
- Compounds 2 and 3 displayed weak emission in low-viscosity solvents due to intramolecular rotation.
- Emission intensity significantly increased with higher solvent viscosity and upon molecular aggregation.
- High fluorescence quantum yields of 0.53 and 0.46 were observed for compounds 2 and 3, respectively.
- X-ray crystallography revealed that weak intermolecular interactions (C-H···F, C-H···π) fix molecular conformations, enhancing solid-state luminescence.
Conclusions:
- The developed organoboron complexes exhibit aggregation-induced emission (AIE) properties.
- Restricted intramolecular rotation and specific intermolecular interactions are key to their enhanced solid-state luminescence.
- These complexes are promising candidates for applications in fluorescence imaging and advanced materials due to their large Stokes shifts and efficient solid-state emission.
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