Syntesis of silver and gold N-heterocyclic carbene complexes and their properties

Recently, N-heterocyclic carbenes and their transition metal complexes have a wide application area in the organometallic chemistry. These complexes showed better catalytic activity than the corresponding phosphine ligands due to their strong ? -donating and weak ? -accepting abilities. In addition, the complexes formed between NHC ligands and metals are more stable than the corresponding analogues phosphine complexes. Since M-NHC bond could stand high temperatures, these complexes could be highly active catalyst. These types of catalytic complexes could act as used in C-C coupling reactions, hydroformylation, olefin metathesis, C-H activation and polymerization. Besides, M-NHC complexes are used widely in medical field. In addition to the antimicrobial effects of these compounds, they were found to be effective against arthritis and cancer. İn this studyimidazolidine and benzimidazole carbene precursors and transition metal complexes have been prepared and their antimicrobial activities were investigated.The results of this study could be summarized in three main sections:1)In the first chapter, 1,3-dialkylbenzimidazolium salts (1a-1d) were prepared and their structure were elucidated by spectroscopic techniques.2)In the second part, Ag (I)-benzimidazolidine (2a-h) and Ag (I)-imidazolidine (3a-b) complexes were synthesized from reaction of Ag2O with the NHC precursors, and all complexes were structurally elucidated by means of spectroscopy.Also synthesized Ag(I)-carbene complexes have been interacted with [AuCl(PPh3)] and Au-NHC complexes (4a-c) have been prepared and the structural characterizations were made by using conventional techniques.3)In the last chapter, the antimicrobial activities of prepared Ag and Au-NHC complexes were investigated.KEYWORDS: N-Heterocyclic carbene, Ag, Au, imidazolidine, benzimidazole, antimicrobial activity.