•A naphthalene benzimidazole-based colorimetric sensor was developed for fluoride ion detection.•Its absorption maximum exhibited 225 nm red shift accompanied with dramatically color change from yellow to blue.•The detection limit for F- was as low as 3.2 × 10-9 mol/L.A novel naphthalene benzimidazole (NBI)-based chemosensor (D2) was developed for fluoride ion (F−) detection. The absorption spectrum of D2 changed dramatically from yellow to blue in the visible region accompanied with a 225 nm red shift of its absorption maximum upon the addition of F− in DMSO. D2 also exhibited a fluorescence turn-off response towards the fluoride ion. The emission intensity of D2 decreased drastically along the increasing F− concentration and the detection limit for F− was as low as 3.2 × 10− 9 mol/L. 1H NMR and HRMS-ESI results indicated that the formation of NBI-O− through the desilylation reaction of F− with NBI-OSi was responsible for the spectral changes. Overall, this kind of NBI-type molecules represent a new type chemosensor for the spectral detection of fluoride ion in solution.Download high-res image (199KB)Download full-size image

A series of novel bridged-neonicotinoid analogues were designed and synthesized, which were constructed by starting material 8 with cyclopentenone or cyclohexenone in the presence of catalyst aluminium chloride. All of the compounds were characterized and confirmed by 1H NMR, 13C NMR, HRMS and IR. The bioassay tests showed that compounds 5 and 6a showed higher bioactivities than imidacloprid against Aphis craccivora.Download high-res image (122KB)Download full-size imageA series of novel bridged-neonicotinoid analogues were synthesized from 6-Cl-PMNI with cyclopentenone or cyclohexenone, and bioassay tests showed that the bioactivities of compounds 5 and 6a were higher than imidacloprid against Aphis craccivora.

A series of novel nithiazine analogues bearing the 1,4-dihydropyridine structure have been designed and synthesized by reaction of nithiazine, malononitrile or ethyl cyanoacetate, and benzaldehyde. The synthesized compounds were identified by 1H NMR and IR spectroscopy, and elemental analysis. Preliminary bioassays indicated that most of the compounds had moderate insecticidal activity against Aphis craccivora. The relationship between molecular structure and biological activity is discussed.

The compound ethyl 6-amino-8-(4-methoxy phenyl)-9-nitro-2,3,4,8-tetrahydropyrido[2,1b][1,3]thiazine-7-carboxylate (C14H22N4O4S2) has been synthesized by multicomponent reactions, and characterized by 1H NMR, IR, and X-ray diffraction. The crystal structure analysis shows that the thiazinane ring displays a half-chair conformation. The benzene ring is almost vertical to the tetrahydro-pyridine ring. Intramolecular H-bonding of N–H···O type exists and completes an S (6) ring. In the crystal, the molecules are connected into a 3D network by a N–H···O and C–H···O intermolecular hydrogen bond. The bioassay indicates that the compound shows moderate insecticidal activity against Aphis craccivora.

The mesoporous material MCM-41 was synthesized by a hydrothermal method, and perylene bisimide dye was incorporated into its channels by impregnation. The absorption, FTIR, fluorescence emission, and decay spectra of perylene bisimide dye in CHCl3 and in MCM-41 were studied to investigate the effect of the one-dimensional channel of MCM-41 on the photophysical and photochemical properties of the dye. The results indicated that the nanochannels of MCM-41 shifted the absorption and emission maxima to red and broadened the spectra, with loss of vibrational structure. The fluorescence decay curves fitted a double-exponential function and the lifetime of perylene bisimide dye in MCM-41 was prolonged. The huge surface area of the mesoporous molecular sieve MCM-41 prevented aggregation of dye molecules, which can thus be used at high concentration.

1,3-Dithiolane-containing nitromethylene derivatives, as candidates for screening as neonicotinoid insecticides, were synthesized by reaction of compound (4) with 1,2-ethanedithiol. Compounds 7a–g were obtained via Mannich reaction of (E)-1-((1,3-dithiolan-2-yl)methyl)-2-(nitromethylene)imidazolidine (6), primary amines and formaldehyde. The synthesized compounds were identified by 1H NMR, IR spectroscopy and elemental analysis. Preliminary bioassays indicated that most of the compounds had moderate insecticidal activity against Aphis craccivora. The relationship between molecular structure and biological activity is discussed.