Synthesis and optical properties of aggregation-induced emission (AIE) molecules based on the ESIPT mechanism as pH- and Zn²⁺-responsive fluorescent sensors

Abstract

A series of schiff base derivatives with salicylaldehyde moieties were designed and synthesized. This materials exhibit typical AIE properties and high fluorescence quantum yields in an aggregated state based on excited-state intramolecular proton transfer (ESIPT) mechanism. Then, the effect of substituted group types and positions on the fluorescence of these novel compounds was investigated through fluorescence spectra analysis and theoretical calculations. And it was found that the salicyaldehyde derives can be used as potential pH and Zn 2+ sensing.A series salicyaldehyde derives with AIE properties were designed and synthesized, which can be used as potential pH and Zn 2+ sensing.

Aggregation‐Induced Emission‐Based Sensing Platform for Selective Detection of Zn2+: Experimental and Theoretical Investigations

“…Various analyte-specific probes for detection of Zn 2 + , Cu 2 + , Hg 2 + and Al 3 + based on such systems have been reported by us. [15] In Table S1, selected aspects of recently published α-hydroxy aromatic Schiff base Zn 2 + sensors [14d,15g,h, [21][22][23][24][25][26][27][28] are compiled, clearly showing that even a slight modification in the chemical structure of a probe may lead to its different photophysical and chemical properties affecting its functionality and applications, such as the limit of detection, selectivity, and also AIEE features. Moreover, depending on molecular structure, a different signaling mechanism may take place.…”

Spectroscopic Studies of Dual Fluorescence in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole: Effect of Molecular Aggregation in a Micellar System

“…Available literature describes the phenomenon of dual fluorescence [ 22 ] as related to the emergence of two clearly separated emission bands [ 23 ]. In which are induced by changes in e.g., the solvent’s polarity, medium’s pH [ 24 ], temperature [ 25 ], of the compound’s concentration. The most popular theories explaining the mentioned fluorescence effects include: the emergence of intramolecular CT states [ 26 ] often involving molecular twist i.e., the so-called Twisted Intramolecular Charge Transfer (TICT) states [ 27 , 28 , 29 , 30 , 31 ], molecular tautomerism emerging in excited states, related to the so-called excited-state proton transfer, i.e., Excited-state Intramolecular Proton Transfer (ESIPT) processes [ 32 , 33 , 34 ].…”

A highly selective aggregation‐induced emission fluorogen for sensitive detection of Al3+ in living cells

“…There was no significant change in fluorescence intensity of probe 1 over the range pH 3–11 (black line) but, when adding Al 3+ , intensity changed at different pH (red line). When pH values were <5, the fluorescence intensity at 455 nm declined rapidly, this decline can be attributed to decomposition of probe 1 in acidic conditions . Fluorescence intensity of probe 1 with Al 3+ increased to a maximum value and kept relatively stable at pH 5–8, but fluorescence decreased rapidly at pH >9.…”