E-ISSN: 2458-973X
Synthesis of pincer type carbene and their Ag(I)-NHC complexes, and their antimicrobial activities
1Department of Chemistry, Trakya University Faculty of Sciences, Edirne, Türkiye
2Department of Chemistry, Tekirdağ Namık Kemal University Faculty of Arts and Sciences, Tekirdağ, Türkiye
Journal of Sustainable Construction Materials and Technologies 2022; 2(7): 53-61 DOI: 10.47481/jscmt.1117139
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In this study, theophylline (1) compounds were synthesized with addition of 2-bromoethanol, 2-bromoacetamide and methyl-2-bromoacetate to attain symmetric connections to NHCs (2a–c). New complexes containing the symmetric N heterocyclic carbene (NHC) ligands were synthesized using azolium salts in dimethyl formamide (DMF). After the NHC predecessor compounds reacted with Ag2O, Ag(I)-NHC complexes were synthesized in the following: 7,9-di-(2-hydroxyethyl)-8,9-dihydro-1,3-dimethyl-1H-purine 2,6(3H,7H)-dionedium silver( I)bromide (3a), 7,9-di(acetamide)-8,9-dihydro-1,3-dimethyl-1H-purine-2,6(3H,7H)-diondium silver(I)bromide (3b) and 7,9-di(methylacetate)-8,9-dihydro-1,3-dimethyl-1H-purine-
2,6(3H,7H)-diondiumsilver(I)bromide (3c). Both synthesized NHC predecessors (2a-c) and Ag(I)-NHC complexes (3a-c) were described by FTIR, 1H-NMR, 13C-NMR, liquid and
solid-state conductivity values, TGA analysis, melting point analysis and XRD spectroscopy. In-vitro antibacterial activities of NHC-predecessors and Ag(I)-NHC complexes were tested
against gram-positive bacteria (Staphylococcus Aureus and Bacillus Cereus), gram-negative bacteria (Escherichia Coli and Listeria Monocytogenes), and fungus (Candida Albicans) in
Tryptic Soy Broth method. Ag(I)-NHC complexes showed higher antibacterial activity than pure NHC predecessors. The lowest microbial inhibition concentration (MIC) value of compound 3a was obtained as 11.56 μg/ml for Escherichia Coli and 11.52 μg/ml for Staphylococcus Aureus. All tested complexes displayed antimicrobial activity with different results.