A new use for an old molecule: N-phenyl-2-(2-hydroxynaphthalen-1-ylmethylene)hydrazinecarbothioamide as a ratiometric ‘Off–On’ fluorescent probe for iron

• Published in: Tetrahedron letters 2012-02, Vol.53 (6), p.670-673
• Main Authors: Marenco, María José Casanueva, Fowley, Colin, Hyland, Barry W., Hamilton, Graham R.C., Galindo-Riaño, Dolores, Callan, John F.
• Format: Article
• Language: English
• Subjects: Fluorescence; Iron(III); Ratiometric; Sensor
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2011.11.126

Probe NT detects Fe(III) from other metal ions in semi-aqueous solution by a ratiometric enhancement in its fluorescent intensity. N-Phenyl-2-(2-hydroxynaphthalen-1-ylmethylene)hydrazinecarbothioamide has been investigated as a fluorescent sensor for the determination of Fe(III) in aqueous solutions. The probe was prepared by the facile Schiff base condensation of 2-hydroxy-1-napthaldehyde with N-phenylhydrazinecarbothioamide. The sensor displayed good selectivity for Fe(III) when tested against a range of biologically and environmentally important cations. A concentration dependent increase in the emission of two fluorescent bands at 425 and 495 nm was observed upon increasing Fe(III) addition resulting in a linear ratiometric response in the 17–37 μM range. The binding stoichiometry was confirmed as 1:1 (host/guest) with the binding constant (log β) calculated as 4.56.