Synthesis of Bioactive N‐Acyclic Gold(I) and Gold(III) Diamino Carbenes with Different Ancillary Ligands

Abstract

A series of gold(I) and gold(III) N‐acyclic diamino carbene (ADC) complexes with different ancillary ligands have been synthesized. The chloride carbene derivatives [Au{C(NHR)(NHCH2py)}Cl] (R = Cy, R = naphthyl, R = xylyl) have been obtained by reaction of 2‐picolylamine with the corresponding [AuCl(CNR)]. The gold(I) thiolate derivatives [Au{C(NHR)(NHCH2py)}(Spy)] were prepared by reaction of the chlorido complexes with 2‐mercaptopyridine (2‐HSpy) in presence of potassium carbonate. The phosphane derivative [Au(pyCH2NH2)(PPh3)](OTf) was obtained by reaction of freshly prepared [Au(OTf)(PPh3)] with 2‐picolylamine. The phosphane‐carbene complexes [Au{C(NHR)(NHCH2py}(PPh3)](OTf) were obtained from the reaction of picolylamino species with the isocyanide. The gold(III) derivative cis‐[Au(C6F5)2(pyCH2NH2)](ClO4) was obtained by the reaction of 2‐picolylamine with freshly [Au(C6F5)2(Et2O)2](ClO4). The reaction of the former with CNCy led to complex cis‐[Au(C6F5)2{C(NHCy)(NHCH2py)}]ClO4 by a nucleophilic attack of the isocyanide to the amine ligand, thus producing a bidentate C,N acyclic carbene ligand. Cytotoxic studies against the tumor human cell lines Jurkat (T‐cell leukaemia), MiaPaca2 (pancreatic carcinoma), A549 (lung carcinoma) and MDA‐MB‐231 (breast carcinoma) showed moderate to good cytotoxic activity for some of the complexes.