7-Dialkylamino-1-alkylquinolinium salts: highly versatile and stable fluorescent probes.
7-Dialkylamino- and 7-alkylsulfenyl-1-alkylquinolinium salts have been synthesized using a novel synthetic approach. The key intermediate, 7-fluoro-1-methylquinolinium iodide, was shown to possess high reactivity toward nitrogen and sulfur nucleophiles, and the kinetics of this nucleophilic aromatic substitution reaction was investigated. A wide variety of compounds were synthesized and characterized spectroscopically. High fluorescence quantum yields were observed, and this was attributed to the rigid molecular architecture. The thermal and photochemical stability of a number of compounds was investigated, and it was demonstrated that 7-dialkylamino-1-methylquinolinium salts have superior stability compared to a number of hemicyanine dyes and rigid charge-transfer probes. Based on the high quantum yields, the large Stokes shifts, and in particular, the high thermal and photochemical stability, it is concluded that 7-dialkylamino-1-methylquinolinium salts are excellent color-shifting, mobility-sensitive fluorescent probes for polymer characterization and other demanding applications.
Faculty of Applied Sciences, Department of Polymer Materials and Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
Otto
O
van den Berg
Wolter F
WF
Jager
Stephen J
SJ
Picken
D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D007700:Kinetics; D015394:Molecular Structure; D010777:Photochemistry; D011806:Quinolinium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D013237:Stereoisomerism; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
D005456:Fluorescent Dyes; D011806:Quinolinium Compounds