Isatinphenylsemicarbazones as efficient colorimetric sensors for fluoride and acetate anions – Anions induce tautomerism

Isatin N-phenylsemicarbazone: effect of substituents and concentration on anion sensing selectivity and sensitivity

“…10 Anion induced tautomerism and the light and thermally initiated mutual E-and Z-isomer transformations of two efficient and easily synthesized isatin N-phenylsemicarbazone colorimetric sensors were investigated in our recent three studies (ESI, Scheme S1 †). [15][16][17] Therein, the interaction of F À , AcO À , H 2 PO 4 À , Br À and HSO 4 À anions with E-and Z-isomers of isatin-3-4-phenyl(semicarbazone) I and N-methylisatin-3-4phenyl(semicarbazone) II as sensors inuenced the equilibrium ratio of the individual sensor tautomeric forms in the liquid phase.…”

Selective detection of Hg2+ ion in aqueous medium with the use of 3‐(pyrimidin‐2‐ylimino)indolin‐2‐one‐functionalized SBA‐15

“…reported some fluorescent dyes based on rhodamine–isatin hybrid molecular architectures for the detection of metal ions . Cigáň's group studied the anion sensing selectivity and sensitivity of isatinphenylsemicarbazone derivatives . Liu et al .…”

Fluorescence of isatin N‐phenylsemicarbazones: aggregation and hydrazide–hydrazonol tautomerism

“…These differences make them very useful for various applications. For example, their optical properties make them suitable as signaling molecules in anion sensors, as they can rapidly switch between two states with different photophysical properties . One of the more interesting and complicating properties is that tautomeric equilibria in the ground state are often vastly different from those in the excited states .…”

“…There are several types of tautomeric equilibria: keto–enol, imine–enamine, nitroso–oxime, azo‐hydrazone, ammonium–azonium, lactim–lactam and so on . In our few previous works, we investigated the interesting solution behavior of substituted isatin N ‐phenylsemicarbazones subjected to unusual hydrazide–hydrazonol tautomeric equilibrium . Depending on concentration and solvent polarity, isatin N ‐phenylsemicarbazones occur in solution as the associated hydrazide form A, monomeric hydrazide form B and a hydrazonol form C .…”