Aggregation-induced emission enhancement upon Al³⁺ complexation with a tetrasulfonated calix[4]bisazacrown fluorescent molecular sensor

Abstract

Aggregation-induced emission and aggregation-induced emission enhancement have attracted much attention due to their great potential in real-world applications. Up to now most of the reports are based on the restriction of free rotation of the luminogens in the aggregates. In the present work, we found that the dansyl fluorophore with typical intramolecular charge transfer characteristic also exhibited aggregation-induced emission enhancement, which was based on the change of micro-environmental polarity of the fluorophore. In the light of the phenomenon, a new water-soluble ligand bearing a tetrasulfonated calix[4]arene was constructed for ratiometric detection of Al(3+) based on an aggregation-induced emission enhancement mechanism. It displayed a distinct selectivity to Al(3+) among the tested cations in lutidine buffer solution (pH 6-7) with a detection limit of 1.8 μM. A reversible response was also demonstrated by the addition of EDTA or F(-).

A metal–organic gel‐based fluorescent chemosensor for selective Al3+ detection

“…The relationship manifested that Ni‐MOG possessed high sensitivity to detect low Al 3+ ion concentration. Based on 3 σ / k , where σ is the standard deviation of the blank and k is the slope of the linear fitting, the limit of detection for Al 3+ ion was calculated to be 0.5 μM, which is much lower than meeting the requirement of WHO with a limit of 7.41 μM Al 3+ in drinking water …”

Pentacenequinone derivatives: aggregation-induced emission enhancement, mechanism and fluorescent aggregates for superamplified detection of nitroaromatic explosives

“…However, the decay time of derivative 5 in 50% water fraction (0.30 ns) is longer than that of 5 in 0% water fraction (0.081 ns) which implies formation of ordered aggregates. 39 We also carried out the uorescence anisotropy studies [40][41][42] of derivative 7 which show an increase in the average anisotropy value of derivative 7 in DMSO from 0.05 to 0.32 in H 2 O-DMSO (1 : 1, v/v) (Fig. S14 and S15 in ESI †).…”

Hydrogen bonding effects in anion binding calixarenes

“…40 Recent work has also shown that aggregation-induced emission can result in enhancement of dansyl fluorescence, however this is accompanied by a significant shift in emission wavelength. 41 Analogous titration with bromide, nitrate and acetate resulted in similar enhancement, with a shoulder appearing to lower wavelength in the case of acetate.…”