2-{2-[4-(Dimethylamino)phenyl]-6-methyl-4H-pyran-4-ylidene}malononitrile: A colorimetric and fluorescent chemosensor for low pH values

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2014-03, Vol.122, p.304-308
• Main Authors: Kim, Dae-Young, Kim, Jae Nyoung, Kim, Hyung Jin
• Format: Article
• Language: English
• Subjects: Fluorescence sensor; Intramolecular charge transfer (ICT); pH sensor; Push–pull conjugate
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2013.11.035

[Display omitted] •We synthesized a new push–pull conjugate (D–π–A structure) dye which displays ICT process.•This dye shows ratiometric pH-sensing in the low pH region.•This dye exhibits a reversible color change from yellow to colorless with increasing pH in the pH range of 0–3.•This dye is also useful as a fluorescent pH sensor for low pH values. For developing intramolecular charge transfer (ICT) chemosensors for low pH values, 2-{2-[4-(dimethylamino)phenyl]-6-methyl-4H-pyran-4-ylidene}malononitrile (DPM) was designed and synthesized. The spectroscopic and pH-sensing properties of DPM were investigated by UV–Vis and fluorescence spectroscopy. This sensor exhibited a pH-dependent ratiometric absorption property in the range of pH 0–3, along with a reversible color change from yellow to colorless with increasing acid concentration. The fluorescence intensity of the sensor was increased with increasing pH within the pH range of 0–2.