Aggregation induced emission (AIE), selective fluoride ion sensing and lysozyme interaction properties of Julolidinesulphonyl derived Schiff base

[Display omitted] •A Julolidine sulphonyl derived Schiff base (JSJ) was synthesized and characterized.•It featured aggregation induced emission (AIE) effect.•JSJ compound was able to detect fluoride ion with high selectivity and exhibited a naked- eye visible color changing from yellow to orange.•The binding ability of JSJ toward biomolecules was investigated through spectral and docking studies. A novel colorimetric and fluorescent chemosensor Julolidinesulphonyl derivative (JSJ) based Schiff base was synthesized in a single-step and characterized by several spectral techniques including FT-IR, 1H NMR, mass spectral and UV–vis absorption, fluorescence methods and elemental analysis. The photophysical property of JSJ compound in various solvents and different pH medium was studied, which showed a remarkable change in its absorption and emission spectra. It also exhibited aggregation induced emission (AIE) behavior in THF:water medium through the formation of nanoaggregates, which have been observed from FE-SEM and AFM techniques. In addition, among all the anions such as F−, Cl−, Br−, I−, SCN−, ClO4−, NO3–, H2PO4− ions, the compound JSJ functioned a selective and sensitive colorimetric sensing ability for F− ion in THF by changing the color from yellow to orange. Based on the experimental results, the detection limit range was found to be 0.23 µM. The detection mechanism may be explained by complex formation at low [F−] via hydrogen bonding interaction while deprotonation of compound JSJ took place at high [F−]. Furthermore, the binding property of compound JSJ with various biomolecules such as Lysozyme (LYZ), L-Valine, Tyrosine and Tryptophan was analyzed through UV–vis absorption and emission spectral methods. Molecular docking study, the most commonly used computational tool for calculating binding affinities and predicting binding sites, was also employed to further characterize the binding site of JSJ toward LYZ.