Synthesis characterization and applications of silver gold and palladium complexes derived from coumarin tethered N heterocyclic carbenes

Abstract

Cancer was responsible for 8.8 million deaths in 2015 and the number is only going to increase newlineas the years progress. As of now, it is the second leading cause of death worldwide and nearly newlineone in every six deaths are due to cancer [http://www.who.int/news room/fact newlinesheets/detail/cancer]. Human body can be affected by 200 different cancers among which the newlinemost common ones are lung cancer, while less common ones are throat, kidney or pancreatic newlinemalignancy. Chemotherapy is one of the most effective modes of treatment to date. Many newlineorganic molecules have been discovered and applied in treating cancer. With the discovery of newlinecisplatin and its anticancer property metal based therapeutic agents found their way in tackling newlinecancer [S. Dasari, 2014:364 378.]. However, most chemotherapeutics like cisplatin have an newlineinherent disadvantage of being extremely toxic to healthy cells as a result present newlinechemotherapeutics fall short in providing quality of life for its users, As a result, a need to newlinedevelop compounds with minimum side effects is the focus of current research. In this aspect, newline5 newline newlineNHC metal complexes of silver(I) and gold(I) can be ideal platinum substitutes. Though gold newlinecompounds can be toxic, it has been shown that their toxicity can be reduced with an newlineappropriate appended ligand [G. Jones, 1996:1154 1158, M. Frezza, 2010:1813 1825] and as newlineof silver it is known to be least toxic to human body with only a known cosmetic side effects, known argeria [P.L. Drake, 2005:575 585]In the last decade palladium has emerged as an excellent catalytic system for C H activation, newlineC C and C N coupling reactions such as Suzuki Miyaura, Heck Mizoroki or Buchwald newlineHartwig, reactions which are the most powerful methods to access biologically relevant biaryl newlineand polyaryl scaffolds. Although the active centres catalyzing the reaction are the metal atoms newlineor ions, the role of the supporting ligand environment is significant and again proved to play a newlinevital role in enhancing the catalytic activity. In this aspect, many known catalysts have been newlinemodified with NHCs in order to tune their stability and performance. newline newline