Synthesis, Structural Analyses And Antibacterial Activities Of New Non-Functionalized And Nitrile-Functionalized Silver(I) N-Heterocyclic Carbene Complexes
| dc.contributor.author | Mohamad Haziz, Umie Fatihah | |
| dc.date.accessioned | 2017-01-12T01:12:07Z | |
| dc.date.available | 2017-01-12T01:12:07Z | |
| dc.date.issued | 2016-09 | |
| dc.description.abstract | Two series of new benzyl substituted benzimidazolium salts, both non-functionalized, (1-3·PF6 and 7-9·2PF6) and nitrile-functionalized, (4-6·PF6 and 10-12·2PF6) were successfully synthesized as N-heterocyclic carbene (NHC) precursors. The reaction of an appropriate ratio of respective benzimidazolium salts with silver(I) oxide facilitated the in situ deprotonation of the benzimidazolium salts that afforded the formation of two series of silver(I)-NHC complexes, [Agn(L)2]·nPF6 (Ag1-Ag12), (where L = 1-6: 1-(2’/3’/4’-methylbenzyl/methylbenzonitrile)-3-(2’’-propyl)benzimidazolium, n = 1 or L = 7-12: 3,3-(butane-1,4-diyl)-1,1-(2’/3’/4’-methylbenzyl/methylbenzonitrile)bisbenzimidazolium, n = 2). The uses of one of the silver(I)-NHC complex, Ag1 as a transfer agent was successfully observed in the formation of a palladium(II)-NHC complex, Pd1 formulated as [PdCl(L)2(MeCN)]PF6 (where L = 1: 1-(2’-methylbenzyl)-3-(2’’-propyl)benzimidazolium). Both the benzimidazolium salts and metal-NHC complexes were characterized by melting point analysis, elemental analyses, FT-IR spectroscopy and 1H and 13C NMR spectroscopy. The 1H spectra of complexes are rather similar to those of the respective salts with the signal for the benzimidazolium H2’ proton completely absent suggesting successful complexation. In the case of 13C NMR spectra of the complex, C2’ carbon resonance appeared as doublets in the downfield region (ca. 185 ppm) confirming the complex formation. The molecular structures of some of the compounds and complexes were established by single crystal X-ray diffraction analyses. Structural analysis indicated that in the absence of any potential hydrogen bond donors or acceptors, various supramolecular interactions played an important role in stabilizing the entire structure. Hence, via all the data obtained, the benzimidazolium salts and metal-NHC complexes were successfully synthesized. Antibacterial studies against a Gram-negative bacteria Escherichia coli (ATCC 25922) and a Gram-positive bacteria Staphylococcus aureus (ATCC 12600), were carried out for all the synthesized benzimidazolium salts and metal-NHC complexes using established methods. All the benzimidazolium salts were inactive while the antibacterial activity of the metal-NHC complexes varied depending on the nature of the ligands. All the mononuclear silver(I)-NHC complexes exhibited medium antibacterial activities while dinuclear silver(I)-NHC complexes were low in the activities compared to the standard antibiotic, ampicillin. The palladium(II)-NHC complex, Pd1 showed only low activities againts S. aureus compared to Ag1 and ampicillin. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3409 | |
| dc.subject | Synthesis, Structural Analyses And Antibacterial Activities Of New | en_US |
| dc.subject | Non-Functionalized And Nitrile-Functionalized Silver. | en_US |
| dc.title | Synthesis, Structural Analyses And Antibacterial Activities Of New Non-Functionalized And Nitrile-Functionalized Silver(I) N-Heterocyclic Carbene Complexes | en_US |
| dc.type | Thesis | en_US |
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