2-Pyridone-based fluorophores containing 4-dialkylamino-phenyl group: Synthesis and fluorescence properties in solutions and in solid state

• Published in: Dyes and pigments Vol. 124; pp. 196 - 202
• Main Authors: Hagimori, Masayori, Shigemitsu, Yasuhiro, Murakami, Ryo, Yokota, Kenichirou, Nishimura, Yasuhisa, Mizuyama, Naoko, Wang, Bo-Cheng, Tai, Chen-Kuen, Wang, San-Lang, Shih, Tzenge-Lien, Wu, Kuen-Da, Huang, Zhi-Shuan, Tseng, Shih-Chuw, Lu, Jian-Wei, Wei, Ho-Hsiang, Nagaoka, Junko, Mukai, Takahiro, Kawashima, Shinichi, Kawashima, Keisuke, Tominaga, Yoshinori
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2016
• Subjects: 2-Pyridone; 6-(4-dialkylamino)phenylpyridone; Fluorescence in solution; Ketene dithioacetal; One-pot synthesis; Solvatofluorochromism; One-pot synthesis; 2-Pyridone; Solvatofluorochromism; Ketene dithioacetal; 6-(4-dialkylamino)phenylpyridone; Fluorescence in solution
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2015.09.017

Novel highly emissive 2-pyridone-based compounds 3a,b and 4a–d were synthesized by a convenient one-pot method from 4-(dialkylamino)acetophenones (1a,b) and cyanoketene dithioacetal (2a) or sulfonyl ketene dithioacetals (2b,c), and their fluorescence properties were investigated. A simple structure modification of 2-pyridones significantly affected their optical properties including the emission wavelength and fluorescence intensity. All the 6-(4-dialkylamino)phenyl-2-pyridones showed positive solvatofluorochromism and intense blue-green fluorescence in nonpolar solvents such as chloroform (Ф: 0.80–0.92) and dichloromethane (Ф: 0.83–0.94). A hypsochromic shift of the fluorescence emission maxima and strong fluorescence in a polar solvent were observed by substituting the dimethylamino group with a diethylamino group. Introduction of a sulfonyl group disturbed the molecular planarity of compounds 4a, 4b, and 4d, resulting in a strong fluorescence in acetone (Ф: 0.86–0.95) and acetonitrile (Ф: 0.59–0.88). These results indicate that 2-pyridone-based compounds have great potential as fluorophores for various practical applications.
•Novel fluorescent 6-(4-dialkylamino)phenyl-2-pyridones were synthesized by a one-pot method.•All the compounds showed positive solvatofluorochromism.•Intense fluorescence was observed in polar and nonpolar solvents.•The sulfonyl group disturbed the molecular planarity, resulting in intense fluorescence in polar solvents.