A chromone Schiff-base as Al(III) selective fluorescent and colorimetric chemosensor

Hydrazone-Based Small-Molecule Chemosensors

“…The wide range of chemical reactivity of hydrazones allows their application in the detection of anions, cations, and other species [10]. Some hydrazone-based chemosensors have weak fluorescence because of quenching effects such as E/Z double bond isomerization in the excited state; photoinduced electron transfer (PET) process (excited electron is transferred from donor to acceptor; generating a charge separation, i.e., redox reaction takes place in excited state); [11] excited state intramolecular proton transfer (ESIPT) process (photoexcited molecule relax their energy through tautomerization by transfer a proton); and others [12,13]. The main objective for this class of chemosensors is inhibiting the quenching effects after interaction with some analytes promoting a fluorescence state.…”

Reversible Colorimetric and Fluorescence Solid Sensors Based on Aryl Hydrazone Derivatives of 1,8-Naphthalimides for Caustic Media and Biogenic Amine Vapors

“…The hydrazone backbone includes an imine carbon with an electrophile character, two nucleophilic nitrogen in both amine and imine groups, and the possible isomerization of the C=N double bond from the conjugation of imine and acid N-H. In certain cases, the long response time or low sensitivity in the presence of analytes is responsible for the weak fluorescence because of quenching effects, such as double-bond isomerization in the excited state, the photoinduced electron transfer (PET) process or the excited-state intramolecular proton-transfer (ESIPT) process [12,13]. Usually, hydrazones are anchored to other fluorophores or aromatic structures such as naphthalimides or coumarins [14][15][16][17][18].…”

A novel off-on fluorescent chemosensor for Al3+derived from a 4,5-diazafluorene Schiff base derivative

“…1 The normal concentration range for aluminum ions in biological systems is narrow, with both deciency and excess causing many pathological states, such as Alzheimer's disease, Parkinson's disease, chronic renal failure, bone soening and smoking related diseases. [2][3][4][5][6] Since there is a close association between Al 3+ and human health, developing uorescent chemosensors with high selectivity and sensitivity for detecting trace amounts of Al 3+ has attracted increasing attention.…”