Palladium(II) N-heterocyclic carbene complexes: synthesis, structures and cytotoxicity potential studies against breast cancer cell line

Mononuclear trans-Pd(II)-NHC complexes (where NHC = N-heterocyclic carbene) bearing asymmetrically substituted NHC-ligand have been synthesized via transmetalation reaction between Ag(I)-NHC complexes and [Pd(NCCH3)(2)Cl-2]. The NHC precursors are accessible in two steps by N-n-alkyl reactions of benzimidazole. The resultant benzimidazolium salts were deprotonated with Ag2O by in situ deprotonation to facilitate the formation of mononuclear Ag(I)-NHC complexes. Single-crystal structural study for Pd(II)-NHC shows that the palladium(II) ion exhibits a square-planar geometry of two NHC ligands and two chloride ions. The cytotoxicity study was investigated against breast cancer cell line (MCF-7). The Ag(I)-NHC complexes exhibit better activities than their corresponding Pd(II)-NHC complexes, whereas all benzimidazolium salts are inactive toward MCF-7 cancer cell line. [GRAPHICS] .