Puhui Xie

A naked-eye, selective and sensitive chemosensor for fluoride ion

Effect of the addition of six different anions on the absorption and fluorescence spectra of acridine yellow G (AYG) was examined. Only the F− anion could induce a visible color change observable with naked eye and a strong fluorescence quenching with KSV of 8.3 × 104 mol−1 L in CH3CN solutions. Calculated results of the interaction between the F− anion and acridine yellow G using the B3LYP/6-31G(d) program showed that the intermolecular charge transfer through the formation of an H-bond between AYG and F− is an essential sensor mechanism.

Synthesis, characterization and antifungal activity of coumarin-functionalized chitosan derivatives

Four novel coumarin-functionalized chitosan derivatives 4a-4d were synthesized via condensation reactions of thiosemicarbazide chitosan with coumarin derivatives. Their structures were confirmed by FT-IR, 13C NMR, XRD and elemental analysis. Their antifungal activities against three kinds of phytopathogens, Alternaria solani sorauer (A. solani), Fusarium oxysporum f.sp. vasinfectum (F. oxysporum) and Fusarium moniliforme (F. moniliforme), were tested using the mycelial growth rate in vitro at 0.1, 0.5, and 1.0mg/mL. The degree of substitution for 4a-4d ranged from 40 to 60%. At 1mg/mL, 4a inhibited F. moniliforme growth by 58.1%, and had an inhibitory index against F. Moniliforme of 77.2%. Derivative 4a was more effective than unmodified chitosan whose antifungal index was 9.7%. The fungicidal tests showed that the synthesized chitosan derivatives have higher activity against the tested fungi compared to unmodified chitosan. Moreover, the introduction of halogen atoms into the chitosan derivatives causes an increase in antifungal activity.

A novel fluorescent turn-on probe for bisulfite based on NBD chromophore

AbstractA novel fluorescent turn-on probe (compound 1) for bisulfite based on 7-nitrobenz-2-oxa-1,3-diazole (NBD) chromophore has been developed. Its sensing behavior toward various anions was investigated by absorption and fluorescence techniques. This probe shows a selective, turn-on fluorescent response and ratiometric colorimetric response toward bisulfite in aqueous acetonitrile solutions. The possible recognition mechanism of probe 1toward bisulfite was illustrated by MS spectra analysis and DFT calculations Probe 1 was used to determine bisulfite in real-life samples with good recoveries. Graphical AbstractA novel fluorescent turn-on probe (compound 1) for bisulfite based on 7-nitrobenz-2-oxa-1,3-diazole (NBD) chromophore has been developed. Probe 1 shows a selective, turn-on fluorescent response and ratiometric colorimetric response toward bisulfite in aqueous acetonitrile solutions.