- Light initiated E-Z and Z-E isomerization of isatinphenylsemicarbazones: Tautomeric equilibrium effect
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The light and thermally initiated mutual E- and Z-isomer transformations of two efficient isatin N-phenylsemicarbazone colorimetric sensors for strongly basic anions differing in sensitivity, selectivity and sensing mechanism were investigated in solvents
- Jakusová, Klaudia,Cigáň, Marek,Donovalová, Jana,Gáplovsky, Martin,Sokolík, Robert,Gáplovsky, Anton
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- Isatin N-phenylsemicarbazone: Effect of substituents and concentration on anion sensing selectivity and sensitivity
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The effect of substituent and concentration on anion sensing selectivity and sensitivity of nine new easily synthesized isatin N-phenylsemicarbazone E-isomer sensors IIIa-XIa was investigated. The substantial difference between the association constants for IIIa-XIa interaction with strongly and weakly basic anions allows detection of F- or CH3COO- anions even at high weakly basic anion excess. Substitution in position 5- of the isatin ring and para-substitution on the phenyl ring in the phenylsemicarbazide chain influence sensor:anion complex stoichiometry and thus also sensor sensitivity. Detection limits of 3-4 × 10-7 mol dm-3 for F- and CH3COO- anions by sensors IVa and Va bearing electron-withdrawing substituents are among the lowest published detection limits for these anions in organic solvents. The high selectivity and sensitivity of sensor VIa allows confident F- detection at tolerated fluoride drinking-water level. The solution dilution leads to a dramatic change in sensor selectivity. Consequently, one E-isomer can be used to sense both strongly and weakly basic anions. On the other side, higher sensor solution concentrations increase the F- and CH3COO- anion detection range, similar to the additional Z-isomer utilization. This journal is
- Cig, Marek,Jakusov, Klaudia,Donovalov, Jana,Sz?cs, Vojtech,Gplovsk, Anton
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p. 54072 - 54079
(2015/01/09)
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- Isatinphenylsemicarbazones as efficient colorimetric sensors for fluoride and acetate anions - Anions induce tautomerism
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The anion induced tautomerism of isatin-3-4-phenyl(semicarbazone) derivatives is studied herein. The interaction of F-, AcO -, H2PO4-, Br- or HSO4- anions with E and Z isomers of isatin-3-4-phenyl(semicarbazone) and N-methylisatin-3-4- phenyl(semicarbazone) as sensors influences the tautomeric equilibrium of these sensors in the liquid phase. This tautomeric equilibrium is affected by (1) the inter- and intra-molecular interactions' modulation of isatinphenylsemicarbazone molecules due to the anion induced change in the solvation shell of receptor molecules and (2) the sensor-anion interaction with the urea hydrogens. The acid-base properties of anions and the difference in sensor structure influence the equilibrium ratio of the individual tautomeric forms. Here, the tautomeric equilibrium changes were indicated by naked-eye experiment, UV-VIS spectral and 1H NMR titration, resulting in confirmation that appropriate selection of experimental conditions leads to a high degree of sensor selectivity for some investigated anions. Sensors' E and Z isomers differ in sensitivity, selectivity and sensing mechanism. Detection of F- or CH3COO- anions at high weakly basic anions' excess is possible.
- Jakusová, Klaudia,Donovalová, Jana,Cigáň, Marek,Gáplovsky, Martin,Garaj, Vladimír,Gáplovsky, Anton
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p. 421 - 429
(2014/02/14)
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- Effect of reactants' concentration on the ratio and yield of E,Z isomers of isatin-3-(4-phenyl)semicarbazone and N-methylisatin-3-(4-phenyl)semicarbazone
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In this work, the effect of inter- and intramolecular interactions of reactants and products, reactants concentration as well as the solvent effect on the ratio of E and Z isomers of isatinphenylsemicarbazones in the reaction mixture is examined. Theoreti
- Jakusova, Klaudia,Donovalova, Jana,Cigan, Marek,Stankovicova, Henrieta,Sokolik, Robert,Gaspar, Jan,Gaplovsky, Anton,Gaplovsky, Martin
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p. 117 - 126,10
(2020/08/24)
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