H-bond stabilization of a tautomeric coumarin-pyrazole-pyridine triad generates a PET driven, reversible and reusable fluorescent chemosensor for anion detection

Polarized Helical Coumarins: [1,5] Sigmatropic Rearrangement and Excited-State Intramolecular Proton Transfer

“…Consequently, we attempted the synthesis of dyes with an additional pyrazolone ring, expecting the appropriate products to possess more rigid geometry. There are many examples described in the literature of pyrazolone ring formation by heating a hydrazine derivative with an appropriate 1,3-dicarbonyl substrate in acetic acid 21 or ethanol. 22 In order to test the suitability of our dyes for this purpose, we performed the reaction of coumarin 3 with phenylhydrazine ( 12 ) by heating the substrates in acetic acid.…”

Recent progress in chemosensors based on pyrazole derivatives

“…The authors also demonstrated the importance of the structural composition in the F À selectivity. 133 A similar approach was conducted by Agarwal et al, who described a low-molecular-weight selective probe for F À detection, compound 25 (Fig. 13c).…”

“…However, further analytical information is needed in order to evaluate the potential applications of this compound. 133 The use of a hydrazone group as a proton source is a recurrent approach in the uoride ion-sensing eld. The combination of stabilizing and/or chromogenic groups has been the design principle of a variety of probes with stupendous results.…”

A multi-colorimetric probe to discriminate between heavy metal cations and anions in DMSO–H2O with high selectivity for Cu2+ and CN−: study of logic functions and its application in real samples

“…Thus, chemosensing has been identied as one of the potential analytical methods used in sensing the presence of cations (mostly heavy metals) and anions in physiological and environmental systems, instead of traditional methods. [10][11][12][13][14][15][16] Chemosensing has become a method of choice in analytical chemistry as it is sensitive and selective to specic target analytes which are ionic or neutral, depending on the design of the sensor. [17][18][19][20][21][22][23][24][25][26][27] This is complemented by the fact that they are easily synthesized, easy to apply, can be applied in real time and are based on naked eye observable colour changes.…”