title: Simple azo-based salicylaldimine as colorimetric and fluorescent probe for detecting anions in semi-aqueous medium.
abstract: A series of novel, highly sensitive, and selective azo-based anion sensors 1-3 have been designed and synthesized from the condensation reaction between 4-amino azo benzene and three different aldehydes. The structure of the sensors 1-3 were confirmed by IR, HRMS, (1)H NMR, and (13)C NMR spectroscopic methods. Colorimetric naked-eye analysis revealed the anion detection by receptors 2 and 3 as color changes from yellow to pink and yellow to orange, respectively. Anion sensing ability of all receptors was further investigated by (1) H NMR titration, UV-vis experiment, and fluorescence titration. UV-vis measurements highly indicate the selective recognition of fluoride and acetate ions in 9:1 dimethyl sulfoxide-H2O (v/v) for receptors 2 and 3. Binding constant value showed among all receptors, receptor 3 has strong affinity toward F(-) and AcO(-) in semi-aqueous medium, which is due to the presence of chromogenic signaling unit in it. The F(-) ion detection property of receptor 2 in organic medium was also extended in the real sample like toothpaste.
authors.affiliation: Organic and Polymer Synthesis Laboratory, Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, India.
authors.forename: Sivalingam
authors.initials: S
authors.lastname: Suganya
authors.forename: Sivan
authors.initials: S
authors.lastname: Velmathi
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis / Q000737:chemistry; D000838:Anions / Q000032:analysis*; D001391:Azo Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D005459:Fluorides / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D062165:Receptors, Artificial / Q000138:chemical synthesis / Q000737:chemistry*; D012459:Salicylates / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017186:Titrimetry / Q000379:methods; D014100:Toothpastes / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000838:Anions; D001391:Azo Compounds; D005456:Fluorescent Dyes; D062165:Receptors, Artificial; D012459:Salicylates; D014100:Toothpastes; D014867:Water; D005459:Fluorides