Abstract

Gold(I) complexes of imidazole and thiazole-based diphos type ligands were prepared and their potential as chemotherapeutics investigated. Depending on the ligands employed and the reaction conditions complexes [L(AuCl)2] and [L2Au]X (X = Cl, PF6) are obtained. The ligands used are diphosphanes with azoyl substituents R2P(CH2)2PR2 as well as the novel ligands RPhP(CH2)2PRPh and R2P(CH2)3PR2 . The cytotoxic activity of the complexes was assessed against three human cancer cell lines and a rat hepatoma cell line and correlated to the lipophilicity of the compounds. The tetrahedral gold complexes [(3)2Au]PF6 and [(5)2Au]PF6 with intermediate lipophilicity (logD7.4 = 0.21 and 0.25) showed significant cytotoxic activity in different cell lines. Both compounds induce apoptosis and inhibit the enzymes thioredoxin reductase and glutathione reductase.