Host-Guest Study of Arylazo Salicylaldehydes-Anions: Colorimetric Chemosensor for Fluoride and Acetate Ions

Colorimetric anion sensing of ۵-aryl azo salicylaldehydes is described via the host-guest (HG) approach. Various anions were tested and the solutions were monitored by UV-Vis spectroscopy. The changes in the color of the azo dye solutions ۱ and ۲ were measured upon exposure to different anions of TBA salts in DMSO as solvent. These changes in color in the case of fluoride and acetate anions were sensible to the naked eye. Spectroscopic data were used to calculate the association constants (Ka ≈ ۱۰۵-۱۰۶) via a non-linear curve fitting approach. Appropriate models for each dye-anion complex (HG) system were assigned based on fitting quality and chemical considerations. The dye: F- system followed the HG model while dye: OAc- seems to follow H۲G model. Observed results persisted for at least one hour and no changes were detectable for the samples even by visual inspection or UV-Vis spectroscopy. The detection limit ranges were calculated to be ۹۵-۱۰۰ µM for F- and ۵۰-۶۰ µM for OAc-.

کلیدواژه ها:

Azo dyes ، Anion ، UV-Vis Spectroscopy