A coumarin-containing Schiff base fluorescent probe with AIE effect for the copper(ii) ion

Abstract

A novel coumarin-derived Schiff base fluorescent “turn-off” chemosensor with AIE effect showed selectivity towards Cu2+. The recognition mechanism is presented.

Synthesis and Aggregation‐Induced Emission of Polyamide‐Amines as Fluorescent Switch Controlled by Hg2+‐Glutathione

“…When the highest content of acetone is 97 %, the system becomes cloudy. This AIE effect is consistent with the reported polymers in the literature [31–33] . From the relationship between fluorescence intensity and acetone content, it can be seen that the aggregation state of PMPBAP has a great impact on the fluorescence intensity.…”

“…This AIE effect is consistent with the reported polymers in the literature. [31][32][33] From the relationship between fluorescence intensity and acetone content, it can be seen that the aggregation state of PMPBAP has a great impact on the fluorescence intensity. The maximum emission fluorescence intensity would be obtained when PMPBAP was in its optimal stacking state.…”

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

“…In 3a and 3b, the electron density of the phenolate oxygen atom was significantly reduced due to the direct conjugation with the strong electron-accepting styrylquinolinizium unit at the neighboring carbon atom C5''. At the same time, imine groups also have a high binding affinity to Cu 2+ [83][84][85] and Fe 3+ [86,87] so that we propose the initial coordination of the metal cation mainly to the imine nitrogen atom of the spirooxazine group in the course of the reaction (Scheme 4, A). Moreover, this explanation is in agreement with the occurrence of the additional set of signals at small copper-to-ligand ratios (Figure 5B,C and Figure S6B,C, Supporting Information File 1, marked with green asterisks) and with the course of the spectrophotometric titration (Figure 2), thus indicating that the initial coordination of the copper ion to the closed form of the spirooxazine was the rate-determining step of the reaction.…”

Fluorescent Schiff base sensors as a versatile tool for metal ion detection: strategies, mechanistic insights, and applications

“…[13][14][15][16][17][18][19] Here, positive metal ion detection may result in visible color change, fluorescence color change, a shift in emission wavelength or intensity (blue-shift or red-shift) or may result in the appearance of new emission maxima. [20][21][22][23][24][25] Fluorescent chemosensors for metal ion detection generally contain Schiff base, [26][27][28] pyridine, 29,30 pyrene, 31,32 anthracene, 33,34 quinoline, 35,36 naphthalene, 37 urea, 38,39 coumarin, 40,41 phenolphthalein, 42,43 and rhodamine 44,45 groups as the binding site. Among various fluorescent chemosensors, Schiff base-based sensors have shown outstanding results owing to their simple synthesis, and provide a suitable electronic and geometrical environment for coordination with single metal ions as well as with multiple metal ions simultaneously.…”