Synthesis, characterisation and biological activity of gold(III) catecholate and related complexes

The reactions of the cyclometallated gold(III) complexes [LAuCl2] [L=2-(dimethylaminomethyl)phenyl, 2-benzylpyridyl or 2-anilinopyridyl] with catechol, tetrachlorocatechol, or the cyclic α,β-diketone SCH(CO2Et)C(O)C(O)CH(CO2Et) give stable complexes containing five-membered Au-O-C-C-O rings. These represent the first examples of well-characterised gold(III) catecholate complexes. Similarly, reactions with 2-acetamidophenol [HOC6H4NHC(O)CH3] give complexes with the related AuNCCO ring. The complexes were characterised by NMR spectroscopy, electrospray ionisation mass spectrometry, elemental microanalysis, and in the case of the complex [(2-benzylpyridyl)Au{OC6H4NC(O)CH3}] by an X-ray crystal structure determination. Several complexes show high activity towards P388 murine leukemia cells.