Synthesis, characterisation and biological evaluation of novel bisimidazolium mononuclear and dinuclear silver(I)-N-heterocyclic carbene complexes with long N-alkyl chains
Document Type
Article
Publication Date
4-1-2024
Abstract
Current drug research has been focusing on silver N -heterocyclic carbene (NHC) complex. Its metal-ligand bonds are stabilised by the strong -electron donor nature of NHC, ultimately increasing its antimicrobial properties. A series of imidazolium salts and their corresponding Ag(I)-NHC complexes with different NHC side chains in terms of alkyl chain length and mono/biscarbene functionalities have been successfully synthesised, characterised, and evaluated for their potential antimicrobial activities. It was shown that the imidazolium salts and Ag(I)-NHC complexes with long aliphatic alkyl N -1/ N -3 side chains and bisimidazolium ligands possess promising bioactivities in general, with minimum inhibitory concentration (MIC) against microbes ranging from 0.12 to 7.81 mu g/mL against selected six Gram-positive bacterial strains ( Staphylococcus aureus and Enterococcus faecalis ), two Gram-negative bacteria ( Escherichia coli and Shigella flexneri ) and two fungal strains ( Candida albicans ) for 2 -7d & Ag-2 -7d . It was found that the compounds with biscarbene structures ( 6d & Ag-6d ) possess less toxic effects against immortalised human keratinocyte (HaCaT) cells. However, it must be noted that the toxic effect against HaCaT is higher among Ag(I)-NHC complexes ( Ag-4d & Ag-6d ) than their corresponding imidazolium salts ( 4d & 6d ) in general. Hence, the variation of side chains, number of imidazolium centres and their respective cytotoxic effect provide insights into the future drug modification towards enhanced antimicrobial activities with minimal side effects.
Keywords
N -heterocylic carbenes, Silver, Imidazolium salts, Ag(I)-NHC complex, Antimicrobial, Cytotoxicity
Divisions
CHEMISTRY
Funders
Ministry of Higher Education (MOHE), Malaysia, under Fundamental Research Grant Scheme (FRGS) (FRGS/1/2018/STG01/MUSM/03/1),Malaysia Toray Science Foundation (MTSF) (CNI-000032),School of Science, Monash University Malaysia
Publication Title
Journal of Organometallic Chemistry
Volume
1009
Publisher
Elsevier
Publisher Location
PO BOX 564, 1001 LAUSANNE, SWITZERLAND