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.
van den Berg
Otto
O
Faculty of Applied Sciences, Department of Polymer Materials and Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
Jager
Wolter F
WF
Picken
Stephen J
SJ
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