Shengling Li,Duanlin Cao,Zhiyong Hu,Zhichun Li,Xianjiao Meng,Xinghua Han,Wenbing Ma
In this study, a highly selective chemosensor ML based on a BODIPY fluorescent chromophore was synthesized for sequential recognition of Cu2+ and HSO3− in a CH3OH/H2O (99 : 1 v/v) system, which contained three recognition sites and its structure characterized by 1H NMR, 13C NMR and ESI-HR-MS. The sensor ML showed an obvious “on–off” fluorescence quenching response toward Cu2+ and the ML-Cu2+ complex showed an “off–on” fluorescence enhancement response toward HSO3−. The detection limit of the sensor ML was 0.36 μM to Cu2+ and 1.4 μM to HSO3−. In addition, the sensor ML showed a 1 : 3 binding stoichiometry to Cu2+ and the recovery rate of ML-Cu2+ complex identifying HSO3− could be over 70%. Sensor ML showed remarkable detection ability in a pH range of 4–8.
Improving the water solubility of natural product cellulose and using it to treat heavy metal ions is very important. In this work, cellulose-based fluorescent probes containing BODIPY fluorophore were synthesized by simple chemical method, which realized the selective recognition and removal of Hg 2+ /Hg 2 2+ ions in an aqueous system. Firstly, fluorescent small molecule (BOK-NH 2 ) bearing -NH 2 group was synthesized through Knoevenagel condensation reaction between BO-NH 2 and cinnamaldehyde. Secondly, via the etherification of -OH on the cellulose, substituents bearing -C ≡ CH groups with different lengths at the end are grafted on the cellulose. Finally, cellulose-based probes (P1, P2, and P3) were prepared by amino-yne click reaction. The solubility of cellulose is improved greatly, especially the cellulose derivative with branched long chains has excellent solubility in water (P3). Benefiting from the improved solubility, P3 could be processed into solutions, films, hydrogels, and powders. Upon the addition of Hg 2+ /Hg 2 2+ ions, the fluorescence intensity enhanced, which are “turn-on” probes. At the same time, the probes could be utilized as efficient adsorbents for Hg 2+ /Hg 2 2+ ions. The removal efficiency of P3 for Hg 2+ /Hg 2 2+ is 79.7 %/82.1 %, and the adsorption capacity is 159.4 mg·g −1 /164.2 mg·g −1 . These cellulose-based probes are expected to be employed in the treatment of polluted environments.
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