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

Application of a quinone-based fluorophore for spectrofluorimetric determination of albendazole in pure form and pharmaceutical formulations

“…Association constant and standard free energy changes 17,18 Association constant. The association constant was determined for the interaction of the ALB-TCNQ complex using a non-linear regression approach and it was found to be 7.28 Â 10 3 mol À1 dm 3…”

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

“…The presence of strongly basic anions leads to the most acidic NH hydrazide group deprotonation and, isatin N ‐phenylsemicarbazone E ‐isomers transform from their self‐associate hydrazide B (keto) form to hydrazonolate (enolate) C form . Acid–base equilibrium shift to hydrazonolate leads to new intensive well‐separated band with maximum in blue UV–Vis region (410 nm).…”

“…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 .…”

“…Acid–base equilibrium shift to hydrazonolate leads to new intensive well‐separated band with maximum in blue UV–Vis region (410 nm). We showed that isatin N ‐phenylsemicarbazones can be useful as selective and very sensitive colorimetric sensors for F − or CH 3 COO − anions (detection limits of 3 − 4 × 10 −7 mol dm −3 ) . Because of their excellent sensitivity in organic media, they can be also used for anion sensing in semi‐aqueous media.…”

A colorimetric and ratiometric fluorescent probe for detection of palladium in the red light region

“…The detection limit of Probe 1 was calculated according to the previous report. [37][38][39][40] The fluorescence emission spectrum of Probe1 was measured by five times to achieve the standard deviation (σ) of blank measurement. 21 In order to obtain the slope (S), the ratio of the fluorescence intensity at 570 nm and 643 nm were plotted as a function of palladium concentration (0−1 μM).…”