ABSTRACT
Herein, we designed two fluorescent tetrasubstituted benzene sulfonyl appended Thiacalix[4]arene receptors named L1 and L2, which sensitively and selectively detect Sulfosulfuron among other herbicides and pesticides. The detection limit (LOD) was found to be 0.21 ppm and 0.35 ppm, and the enhancement constant (Ks) was determined to be 7.07 X 104 M-1 and 5.55 X 104 M-1 for L1 and L2, respectively. Using the non-linear regression method, the association constant was obtained as 2.1 X 104 M-1 and 2.23 X 104 M-1 whereas, the binding ratio was found to be 1:1 for both L1 and L2, respectively. Additionally, the interference studies show the selective nature of receptors for Sulfosulfuron among its sulfonylurea family. To further confirm the interaction mechanism, 1H-NMR spectroscopy, and a computational investigation were carried out, which validates the 1:1 binding ratio. The receptors were found to be recyclable in nature with simple acid-base treatment. This new approach of using supramolecules as fluorescent probes for sensitive and selective detection of herbicides is rare in the literature.
ABSTRACT
A new tri-naphthoylated Cyclotriveratrylene molecule has been synthesized for the rapid and sensitive detection of 4-nitrotoluene (4-NT) among various nitro aromatic compounds (NACs) by using a spectrofluorimetric method. The newly derrivatized cyclotriveratrylene compound is successfully confirmed by using the available techniques of 1H-NMR, 13CNMR, and ESI-MS. This synthesised molecule is 1NC-CTV (1-Naptholy Chloride-Cyclotriveratrylene). Strong quenching in the fluorescence intensity of 1NC-CTV was observed upon the addition of 4-NT. Further quantum yield studies were carried out and by using the stern volmer it was concluded that the fluorescence quenching mechanism is dynamic or static. The molecule 1NC-CTV was further studied with the help of computational methods such as molecular docking to study the binding interactions and properties of the molecule.