Synthesis, Characterization And Biological Studies Nitrile-Functionalized And Non-Functionalized Silver(I)-N-Heterocyclic Carbene Complexes
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Date
2015-05
Authors
SZE YII, CHOO
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Abstract
This thesis describes the synthesis of six new benzimidazolium salts (1∙PF6-6∙PF6) and their corresponding silver(I)-NHC complexes (7-12). All the synthesized compounds were tested for their potential as possible antibacterial and anticancer agents. Succesive N-alkylation method was adopted to produce benzimidazolium salts in good yields (79.7-91.8%). These benzimidazolium salts were then treated with silver oxide to afford silver(I)-NHC complexes in moderately good yields (65.4-73.9%). The reported compounds were characterized using different spectro-analytical techniques viz., 1H, 13C NMR, FT-IR spectroscopies and elemental analysis. The structure of one benzimidazolium salt (2∙PF6) and four silver(I)-NHC complexes (7, 8, 9, and 11) were established through single crystal X-ray diffraction (XRD) analysis. All the prepared compounds were non-hygroscopic and stable towards air, moisture, and heat. All the benzimidazolium salts and their silver(I)-NHC complexes were tested for antibacterial activity against Escherichia coli (Gram-negative) dan Bacillus subtilis (Gram-positive) with ampicillin used as standard drug (18±1 mm diameter zone of inhibition). The benzimidazolium salts showed no inhibition activity against both bacterial strains. Silver(I)-NHC complexes 8 and 10 showed the strongest inhibition activity at 12 μL against E. coli (26±1 mm diameter zone of inhibition) and B. subtilis (20±1 mm diameter zone of inhibition), respectively. The in vitro anticancer activity of all benzimidazolium salts and their silver(I)-NHC complexes were tested against the human colorectal cancer cell line (HCT 116) with 5-fluorouracil as the standard drug (IC50= 5.2 ± 0.3 μM). Among the benzimidazolium salts, 2∙PF6 displayed the strongest anticancer activity
with IC50 values of 15.2 ± 1.5 μM while among the silver(I)-NHC complexes, 7 exhibited the strongest anticancer activity with IC50 values of 10.5 ± 1.0 μM.
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Keywords
Biology Science , Non-Functionalized Silver(I)-N-Heterocyclic Carbene Complexes