1 research outputs found
Pyrene Scaffold as Real-Time Fluorescent Turn-on Chemosensor for Selective Detection of Trace-Level Al(III) and Its Aggregation-Induced Emission Enhancement
A pyrene
based fluorescent probe, 3-methoxy-2-((pyren-2yl-imino)Âmethyl)Âphenol
(HL), was synthesized via simple one-pot reaction from inexpensive
reagents. It exhibited high sensitivity and selectivity toward Al<sup>3+</sup> over other relevant metal ions and also displayed novel
aggregation-induced emission enhancement (AIEE) characteristics in
its aggregate/solid state. When bound with Al<sup>3+</sup> in 1:1
mode, a significant fluorescence enhancement with a turn-on ratio
of over âŒ200-fold was triggered via chelation-enhanced fluorescence
through sensor complex (Al-L) formation, and amusingly excess addition
of Al<sup>3+</sup>, dramatic enhancement of fluorescence intensity
over manifold through aggregate formation was observed. The 1:1 stoichiometry
of the sensor complex (Al-L) was calculated from Jobâs plot
based on UVâvis absorption titration. In addition, the binding
site of sensor complex (Al-L) was well-established from the <sup>1</sup>H NMR titrations and also supported by the fluorescence reversibility
by adding Al<sup>3+</sup> and EDTA sequentially. Intriguingly, the
AIEE properties of HL may improve its impact and studied in CH<sub>3</sub>CNâH<sub>2</sub>O mixtures at high water content. To
gain insight into the AIEE mechanism of the HL, the size and growth
process of particles in different volume percentage of water and acetonitrile
mixture were studied using time-resolved photoluminescence, dynamic
light scattering, optical microscope, and scanning electron microscope.
The molecules of HL are aggregated into ordered one-dimensional rod-shaped
microcrystals that show obvious optical waveguide effect