A Novel Benzimidazole-Based Chemosensor for Fluorometric Determination of Zinc Ions.

A simple and novel Schiff base chemosensor (BMHM) based on benzimidazole was synthesized. In ethanol-water (1:1, v/v) medium on varying concentrations of Zn2+ chemosensor exhibited a strong and quick turn on fluorescence response. The Zn2+ recognition was based on the Chelation-enhanced fluorescence effect. The binding constant and limit of detection for BMHM-Zn2+ complexation were estimated to be 7.99 × 104 M-1 and 0.148 µM, respectively. The extreme fluorescent enhancement caused by Zn2+ binding in chemosensor BMHM occurred at a pH range of 6-7. The practical use of chemosensor BMHM was tested by determination of Zn2+ in real water samples and comparing the results with the data obtained using high resolution inductively coupled plasma mass spectrometry.

2,5-Di-bromo-3,6-dimeth-oxycyclo-hexa-2,5-diene-1,4-dione.

In the structure of the title compound, C8H6Br2O4, the complete mol-ecule is generated by the application of a centre of inversion. The mol-ecule is planar (r.m.s. deviation for all non-H atoms but methyl C = 0.0358 Å), with only the methyl groups being deviated from the plane [by ±0.321 (4) Å]. In the crystal packing, Br⋯O(methoxy) halogen bonds [3.2407 (19) Å] connect molecules into supramolecular layers parallel to (101).

Synthesis, antibacterial and antifungal activities of electron-rich olefins derived benzimidazole compounds.

New benzimidazole derivatives were synthesised by electron-rich olefines (7, 8 and 9) with appropriate reagents. The compounds synthesised were identified by 1H NMR, 13C NMR, FT-IR spectroscopic techniques and elemental analysis. All compounds studied in this work were screened for their in vitro antimicrobial activities against the standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and the yeasts Candida albicans and Candida tropicalis. Eleven of the compounds inhibited the growth of gram-positive bacteria (E. faecalis and S. aureus) at MIC values between 50 and 400 microg/ml. None of the compounds exhibit antimicrobial activity against Gram-negative bacteria (E. coli and P. Aeruginosa) at the concentrations studied (6.25-800 microg/ml). Nine of the tested compounds showed an antifungal activity with a range of the MICs between 50 and 400 microg/ml.