Novel chiral aggregation induced emission molecules: self-assembly, circularly polarized luminescence and copper(ii) ion detectionElectronic supplementary information (ESI) available: Materials, instruments and methods; fluorescence images of 1 and 2; absorption spectra and fluorescence intensity of 1 upon the addition of various metal cations; absorption and fluorescence titration spectra, Job's plot, mass spectrum of 2 with Cu2+; NMR and mass spectra of 1-3. See DOI: 10.1039/c8qm00294k

• Main Authors: Huang, Guangxi, Wen, Rongsen, Wang, Zhiming, Li, Bing Shi, Tang, Ben Zhong
• Format: Article
• Language: English
• ISSN: 2052-1537
• DOI: 10.1039/c8qm00294k

This work provides a feasible strategy for future design of CPL materials and ion sensors. By introducing chiral alanine to hydrazone derivatives, two novel chiral molecules 1 and 2 with aggregation-induced emission enhanced (AIEE) characteristics were designed and synthesized. Molecule 1 had the two phenyl groups connecting to hydrazone covalently bonded, so its fluorophore is more conjugated than that of 2 . This subtle structural variation between 1 and 2 had a considerable influence on their photophysical properties, chiral optical properties and self-assembly behaviors. Both kinds of molecules could self-assemble into long helical nanofibers with lengths up to several microns upon aggregation. They both possessed AIEE properties, but 1 emitted red fluorescence and 2 had yellow fluorescence upon aggregation. They also had aggregation induced circular dichroism (CD) and circularly polarized luminescence (CPL) properties, but 1 had better performance because its fluorophore was more conjugated than that of 2 . However, only 2 had a specific interaction with Cu 2+ and it showed a highly selective and sensitive "turn-off" fluorescence response to Cu 2+ . Two novel chiral molecules 1 and 2 were designed and synthesized. 1 displayed evident CPL activity, whereas 2 served as a highly selective and sensitive "turn-off" fluorescent chemosensor for Cu 2+ .