Schiff base derived from salicylaldehyde‐based azo dye as chromogenic anionic sensor and specific turn‐on emission sensor for cyanide ion

Abstract

A novel Schiff base has been derived from condensing 4‐aminoantipyrine with diazotized salicylaldehyde. The derived compound acted as a colorimetric sensor for hazardous aqueous anions like CN−, F−, and CH3COO− among a list of anions. The colorimetric changes were further verified through absorption titrations. The detection limits were of the order of 10−10 M, which makes the sensor significant. The interaction of the anions with the sensor was stoichiometrically 1:1 with good binding constants. The sensor turns out to be a specific turn‐on emission sensor for CN− even in competitive environments. The F− ion sensing ability was extended to the determination of F− in a commercial toothpaste with good results.

Effect of conjugation in 4-amino phenazone based Schiff bases on their chemosensing of F- and OH- ions - Experimental and DFT study

“…[26,27] Chemosensing provides a reliable method for detection of hydroxyl ions which is not possible with other techniques like glass electrodes, as it becomes inaccurate and insensitive to OH − ions at higher pOH values. [27] Literature suggests that the Schiff bases contained phenolic, [20,24,[28][29][30][31] hydrazine, [22,[32][33][34][35][36][37][38][39][40] azole, [41][42][43] hydrazone,[26, [44][45][46] salicylidene, [47,48] salicylaldehyde, [49,50] azo dyes, [51,52] naphthaldehyde [53,54] naphthoquinone [60], hydrazone [26] and phenol [20] moieties have anion detection properties such as uoride and hydroxide. Still there is room to explore compounds that can selectively and sensitively sense anion in terms of their binding constants and limit of detection.…”