Gold(III) and gold(I) complexes with anti-tumour activity with similar structures to Auranofin and cis-platin.

The 'hardness' and 'softness' of metal ions and ligands correlates with their polarizabiliry: Metal ions which are small and highly charged e.g. Au(III), and ligands which are small and electronegative, are 'hard', Large, polarizable metal ion or ligand donor atoms are 'soft', The trans-influence is the influence that a ligand has on the strength of the metal-ligand bond trans to itself and increases with the softness of the influencing ligand and influences drug activity. The sequence of increasing softness of some common ligands is: Cl- < Br- < RS- < R3P <ylide < Ar- < R-. Our research has thus been aimed at synthesising similar molecules to test for their anti-tumour properties.