Selective and Sensitive Discrimination of Zinc and Cadmium Based on a Novel Fluorescent Porous Organic Polymer

Abstract

Zinc and cadmium are two main transition metal ions and play profound important roles in environmental and human health. But the distinctive detection of these two ions is still challenging since they belong to the same periodic group and have similar chemical properties. A fluorescent bipyridine-based porous organic polymer (Bpy-POP) containing aggregation caused quenching (ACQ) units (anthracene) and metal ions recognition units (bipyridine) was synthesized through the Schiff base condensation reaction. In the DMF/H 2 O mixtures with the water fractions of 90%, the Bpy-POP aggregated and the fluorescent Bpy-POP quenched subsequently due to the ACQ effect of anthracene in the skeleton ("OFF" state). With the addition of Zn 2+ or Cd 2+ , however, the strong coordination of the bipyridine units from the adjacent Bpy-POPs with Zn 2+ or Cd 2+ induced the partial dispersion of large Bpy-POP aggregates. Consequently, the fluorescence intensities enhanced dramatically as well as the fluorescence emission shifted to redder region, showing an "ON" state. Combing the fluorescence increasing efficiency and the maximum emission wavelength shift degree together, Zn 2+ and Cd 2+ can be selectively discriminated and quantitatively detected, which exhibits a great promising of the present Bpy-POP based method in Zn 2+ and Cd 2+ monitoring in real samples.

Determination of the critical micelle concentration of surfactants using fluorescence strategies

“…Fluorescent sensors generally show characteristic fluorescence in the ultraviolet-visible-near infrared (UV-Vis-NIR) region, [22][23][24] and their fluorescence properties (such as excitation and emission wavelengths, intensity, lifetime, etc.) change sensitively with the analytes of interest and their surrounding environments (such as polarity, temperature, viscosity, etc.).…”

Steric Barrier‐Steered Reaction Sites in Micellar Catalysis

“…[ 23 ] At concentrations of 5–12 µ m , the fluorescence intensity of DBT in the C 8 ‐TPE‐C 4 TAB and C 4 ‐TPE‐C 8 TAB micelles decreased with increasing the concentration, implying a significant ACQ effect. [ 24–26 ] In contrast, the fluorescence intensity of DBT in the TPE‐C 12 TAB micelles increased with the increase of concentration, which suggested a nonaggregation behavior. These distinct differences in the fluorescence trends indicated that DBT was solubilized to different sites inside the three micelles.…”

Assembling aggregation‐induced emission with natural DNA to maximize donor/acceptor ratio for efficient light‐harvesting antennae

“…However, such a close packing of donor chromophores would induce intractable aggregation-caused quenching (ACQ) problem. [30][31][32][33][34] To mitigate these barriers, the larger donors with a binding site size of 2 base pairs or base-specific donors were favored to avoid aggregation. [34] However, these strategies could significantly decrease the binding number of donor chromophores, resulting in a lower donor/acceptor ratio.…”