A stability comparison and antimicrobial evaluation of gold N-heterocyclic carbenes and their silver precursors

The synthesis of the first metal N-heterocyclic carbene (NHC) complexes by Ofele and Wanzlick started an exciting new class of coordination chemistry. The isolation of the first free carbene by Arduengo provided a novel route from which numerous NHC metal complexes have been made. Among their many applications, the potential for therapeutic use has been an area of growing interest and a topic of this review. The first gold NHC complex synthesized from its silver NHC precursor by Lin revolutionized the frontier for simple gold NHC generation to which this review is rooted.;Chapter 1 provides a review on past and current routes by which gold(I) and gold(III) NHC complexes have been synthesized. The discussion focuses on their structural comparisons and a detailed history of the medicinal use of gold is presented before exploring their current role in the field. In Chapter 2, the stability of gold-(bis)NHC complexes in aqueous and physiological solution is discussed in comparison to their silver-(bis)NHC precursors. Silver has been used as an antimicrobial agent for thousands of years and the antimicrobial properties of both are explored. Chapter 3 focuses further on water stability and antimicrobial properties as it is applied to silver acetate NHC complexes in comparison to silver- and gold-(bis)NHC analogues.;Imidazolium salts, NHC precursors, have been shown to possess antimicrobial properties. Chapter 4 investigates these properties on synthesized imidazolium salts with a variety of functional groups on varying positions of the imidazole ring. There are several different types of silver dressings commercially available. Chapter 5 evaluates the antimicrobial effectiveness of eight such dressings and comparisons are made.