Novel symmetrical and non-symmetrical 11th group-NHC complexes: synthesis, cytotoxicity and solution behavior

As potential anticancer drugs, N-Heterocyclic Carbene (NHC) complexes constitute a recent and fruitful field of research [1]. Our research group, during the last 7 years, has developed different classes of coinage metal-NHC complexes. Recently we have focused the research work on the development of new silver(I)-, gold(I)- and copper(I)-NHCs complexes obtained from the water soluble ligands HIm1R,3RCl (R = COOCH3, COOCH2CH3 or CON(CH2CH3)2) [2] or the zwitteronic symmetrical NHC ligands NaHIm1R,3R,4R’’ (R = (CH2)3SO3-, R’’ = H, CH3) [3, 4] (Figure 1), NaHBzim1R,3R (R = (CH2)3SO3-) and non-symmetrical NHC ligands NaHIm1R,3R’ (R = (CH2)3SO3-, R’ = CH2C6H5), {[HBzim1R,3R’]Br} (R = (CH2)3SO3Na, R’ = CH2C6H5) and the related copper(I)- and silver(I)-NHC complexes [4]. We have also investigated the coordination ability of the new ligand {[HTz(pNO2Bz)2]Br} towards Ag(I), Au(I) and Cu(I) acceptors [5]. The cytotoxic activity of the NHC complexes has been investigated.