Fluorescence characteristics of 5-amino salicylic acid: An iodide recognition study

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2012-08, Vol.94, p.119-125
• Main Authors: Arora, Priyanka, Suyal, Kanchan, Joshi, Neeraj K., Joshi, Hem Chandra, Pant, Sanjay
• Format: Article
• Language: English
• Subjects: 5-Aminosalicylic acid; Enhancement; ESIPT; Hydrogen bonding; Iodide
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2012.03.056

[Display omitted] ► Effect of iodide on the fluorescence of 5-amino salicylic acid is studied. ► The effect of hydrogen bonding as well as the interplay of neutral/ionic species is invoked to explain the observations. ► The study projects the application of this system in iodide recognition in physiological environments. In this paper we report the effect of iodide on the fluorescence of 5-amino salicylic acid (5-ASA). In the absence of iodide, prominent blue green (BG) emission band at ∼465nm (broad) is observed in aprotic solvents whereas violet (V) emission at ∼408nm, blue green (BG) at ∼480nm and green (G) at ∼500nm are observed in case of protic solvents. On the addition of iodide ion (I−), the intensity of BG fluorescence is enhanced in case of aprotic solvents. On the other hand the G band is enhanced in protic solvents and decrease in the intensity of the V band is observed. The effect of hydrogen bonding as well as the interplay of neutral and ionic species is invoked to explain the observed results. The study projects the application of this system in iodide recognition in protic/aprotic environments.