P. Vijayakumar^1,, M. Arockia Doss^2,, S. Nargis Negar³ and R. Renganathan^1,*,

¹School of Chemistry, Bharathidasan University, Tiruchirappalli-620024, India

²Department of Chemistry, St. Joseph University, Nagaland-797115, India

³Department of Nanoengineering, Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania

*Corresponding author: E-mail: rrengas@gmail.com

A novel Schiff base derivative E-4-((1-(10H-phenothiazin-2-yl) ethylidene)amino)-N-(pyrimindin-2-yl)benzenesulfonamide (BT) was synthesized and characterized by ¹H & ¹³C NMR, FT-IR and mass spectrometry. Compound BT acts as a detector for Al³⁺ in ethanol/water HEPES buffer solution (5 mM, pH 7.4, v/v 1:4) at room temperature. The fluorescence intensity observed at 516 nm was increased due to Al³⁺ ion present with a fluorescence response “turn-on” process, when excited at 290 nm. This shows compound BT is coordinated to Al³⁺ ion through the NH group and C=NH of the Schiff base blocking the photoinduced transfer (PET) and chelation induced enhanced fluorescence (CHEF) process, to increase the fluorescence intensity of BT. The detection limit of BT was in a micro-molar range for Al³⁺ ion, confirming high selectivity and sensitivity of BT. The BT-Al³⁺ ion binding mode and the recognition mechanism of chemosensor were explored by EDTA titration, Job’s plot, Mass and FT-IR analysis. The theoretical support was established by DFT calculations.

Benzenesulfonamide, Chemosensor, Photoinduced electron transfer, EDTA, DFT.