Recent Developments in the Medicinal Applications of Silver-NHC Complexes and Imidazolium Salts

Abstract

Because of their great structural diversity and multitude of chemical properties, N-heterocyclic carbenes (NHCs) have been utilized in a variety of capacities. Most recently, NHCs have been utilized as carrier molecules for many transition metals in medicinal chemistry. Specifically, Ag(I)-NHCs have been investigated as potent antibacterial agents and chemotherapeutics and have shown great efficacy in both in vitro and in vivo studies. Ag(I)-NHC compounds have been shown to be effective against a wide range of both Gram-positive and Gram-negative bacterial strains. Many compounds have also shown great efficacy as antitumor agents demonstrating comparable or better antitumor activity than standard chemotherapeutics such as cisplatin and 5-fluorouracil. While these compounds have shown great promise, clinical use has remained an unattained goal. Current research has been focused upon synthesis of novel Ag(I)-NHC compounds and further investigations of their antibacterial and antitumor activity. This review will focus on recent advances of Ag(I)-NHCs in medicinal applications.

Metal complexes as a promising source for new antibiotics

“…39 NHC-silver carbenes are amongst the more intensely investigated metal complexes for antibacterial activity, and many more silver compounds have been reported, with the results summarized in several review articles. [40][41][42] Furthermore, new advances have revealed detailed information on possible modes of action for silver-based antimicrobial compounds. 43,44 Silver itself is known to be an antimicrobial agent, with varying activity depending on form (salts vs. nanoparticles vs. colloidal forms), so analysis of activity of silver complexes is complicated by this inherent activity.…”

Catalytically Active N‐Heterocyclic Carbene Release from Single‐Chain Nanoparticles Following a Thermolysis‐Driven Unfolding Strategy

“…Moreover, thanks to the high accessibility and versatility of NHCs, several functionalized architectures can be achieved from Ag(I)‐NHC complexes for different applications, such as antibacterial agents or catalysis . In particular, a promising synthetic strategy inspired by nature has emerged to prepare unimolecular versatile nano‐objects referred to as single‐chain nanoparticles (SCNPs) .…”

“…Thus, in comparison to the approaches used to produce Znand Sn-NHC complexes, [19] the free carbenes do not interfere with the synthesis of Ag(I)-NHC, allowing to achieve good yields using standard laboratory techniques. [6,11,13,20,21] Moreover, thanks to the high accessibility and versatility of NHCs, several functionalized architectures can be achieved from Ag(I)-NHC complexes for different applications, such as antibacterial agents [18,22] or catalysis. [23][24][25][26] In particular, a promising synthetic strategy inspired by nature has emerged to prepare unimolecular versatile nano-objects referred to as single-chain nanoparticles (SCNPs).…”

Synthesis, Characterisation and Antimicrobial Studies of some 2,6‐bis(1,2,3‐Triazol‐4‐yl)Pyridine Ruthenium(II) “Click” Complexes

“…Metal complexes have been shown to have promise as antibacterial agents . It has long been known that metal ions possess antibacterial properties, and a variety of metal complexes have recently been used to inhibit the growth of bacteria, including systems based on iron, copper, silver,, rhenium, and gold . Additionally, when compared to organic antimicrobial drugs, metal complexes offer different molecular shapes (e. g. square planar and octahedral) and readily tuned charge/oxidation states.…”