Wavelength-tunable fluorophores based on quinoline fused α-cyanovinyl derivatives: Synthesis, photophysics properties and imaging

作者：Yu, Wei; Wang, Lihong; Zhang, Nuonuo^*; Yan, Jiaying; Zheng, Kaibo^*

来源：2022, 104: 153996.

DOI：10.1016/j.tetlet.2022.153996

• Organic fluorophores
• NIR
• Quinolines-fused alpha-cyanovinyl
• "pull-push" systems
• Imaging

In this paper, we designed and synthesized six 6-substituted quinolines-fused alpha-cyanovinyl derivatives QM-1 similar to 3 and QS-1 similar to 3 through pi-expansion system with "pull-push" systems. QM-1 similar to 3 and QS-1 similar to 3 have large absorption extinction coefficients. QM-1 similar to 2 and QS-1 similar to 2 (H-, CH3O-) showed blue/green fluorescence emission. However, QM-3/QS-3 ((CH2CH3)(2)N-) exhibited large bathochromic shifts in emission maxima of QM-3 (form 544 to 627 nm), QS-3 (from 570 to 668 nm), large stokes shifts and relatively high fluorescent quantum yields (Phi(QM-3,max )= 0.49, Phi(QS-3,max) = 0.25) in different polar solvents. The results of emission spectra in water/DMSO mixtures (lambda(QM-3,max) = 655 and lambda(QS-3), max = 687 nm) and DFT calculations further proved that QM-3/QS-3 had a significant intramolecular charge transfer (ICT) process. Moreover, QM-3 and QS-3 were suitable for fluorescence bio-imaging.