Cancer chemotherapy is dominated by platinum-based compounds that are currently the world's best-selling anticancer drugs.¹ However, platinum compounds have drawbacks that include side effects and intrinsic or acquired resistance. There is a renewed interest in the study of gold compounds as an alternative to platinum drugs.² While the mechanism of action for platinum relies on covalent binding to DNA purine bases, it seems that gold compounds behave in a different way (most plausibly by interference with mitochondrial functions).³

We present here the synthesis of organogold(III) compounds containing iminophosphorane ligands with a pincer C,N backbone (figure 1) that stabilize the oxidation state III and a phosphine fragment very useful to study reaction mechanisms by ³¹P NMR. Reactions of the precursor [Au{k₂-C,N-C₆H₄(PPh₂=N(C₆H₅)-₂}Cl₂] (1)⁴ with dithiocarbamates (NaS₂CNR₂; R= Me, Ph) and NaPF₆ afford stable cationic compounds [Au{k₂-C,N-C₆H₄(PPh₂=N(C₆H₅)-₂}(S₂CNR₂)]PF₆ (2,3) that are soluble in dimethylsulfoxide. Water-soluble compounds of the type [Au{k₂-C,N-C₆H₄(PPh₂=N(C₆H₅)-₂}Cl(PR₃)]BF₄ (4,5) have been also prepared by reaction of 1 with AgBF₄ and a water soluble phosphines (P(C₆H₄SO₃Na)₃; PR(C₆H₄SO₃Na)₂: R = Cp).

Preliminary studies on the cytotoxicity of these compounds against cis-platin sensitive and resistant cell lines will be presented along with studies on their interaction with DNA.

1.    Kelland, L. Nature Rev. 2007, 7, 573.

2.    Guo, Z.; Sadler, P.J. Angew. Chem. Int. Ed. 1999, 38, 1512.

3.    Barnard, P.J.; Berners-Price, S.J. Coord. Chem. Rev. 2007, 251, 1889.

4.    Aguilar, D.; Contel, M.; Navarro, R.; Urriolabeitia, E.P. Organometallics 2007, 26, 4604.