No abstract

Sixteen new acylhydrazone derivatives and twelve intermediates were synthesized using substituted aromatic acids as the staring materials. The structures of the target compounds and intermediates were characterized by IR, NMR and elemental analyses. And that the geometrical isomers of target compounds undergo a rapid cis/trans equilibrium, with the trans conformer predominating at room temperature. The auxin activity test showed that the target compounds have different effect on wheat gemma, the antibacterial activity was present in almost all the target compounds, but better activity was observed against Staphylococcus aureus than Escherichia coli. Particularly compound 4h exhibits higher antibacterial activity to Staphylococcus aureus than the others. The minimal inhibitory concentration (MIC) of 4h with Staphylococcus aureus is 3.13 μg/mL which is similar with chloramphenicol.

Three novel carbazole-thiosemicarbazides based Schiff-base were synthesized. The recognition ability of representive 2-((N-heptane-carbazol-3-yl)methylidene)hydrazine carbothioamide (L 2 ) to metal ions was investigated by naked-eye, UV-Vis, fluorescence and mass spectra. The experimental results showed that this compound had a good water solubility and can be investigated in DMSO-H 2 O (V∶V＝6∶4, Tris-HCl buffer, pH＝7.0). The compound L 2 in the DMSO-H 2 O displayed a distinct color change from colorless to yellow upon the addition of Cu 2＋ , other metal ions did not induce significant colour changes, which indicated that Schiff base L 2 can be used as a probe with naked eye detection for Cu 2＋ . The fluorescence spectra showed that the probe L 2 was a high selective and sensitive "turn-off" fluorescence probe for Cu 2＋ in DMSO-H 2 O (V∶ V＝6∶4, Tris-HCl buffer, pH＝7.0). The association constant between the probe L 2 and Cu 2＋ was detected to be 3.42×10 4 L•mol -1 , and the detection limit was calculated to be 8.96×10 -6 mol•L -1 . MS analysis showed a 1∶1 binding stoichiometry between Cu 2＋ and L 2 . The detection limit of L 2 for Cu 2＋ was far lower than the maximum allowable level of World Health Organization (WHO) limit (20 mol•L -1 ) for drinking water.