Organogold(III) complexes containing chelating bis(amidate) ligands: Synthesis, characterisation and biological activity

Abstract

Reactions of cycloaurated gold(III) dichloride complexes, with 1,2-C 6H 4(NHCOMe) 2 and silver(I) oxide, or with C 2H 4(NHSO 2Tol) 2 (Tol = p-tolyl) or 1,2-C 6H 4(NHSO 2Tol) 2 and trimethylamine, give a series of new auracyclic complexes containing the Au–NR–CH 2CH 2–NR (R = SO 2Tol) and Au–NR–C 6H 4–NR (R = COMe or SO 2Tol) five-membered ring systems. An X-ray structure determination on (2-bp)Au{N(COMe)C 6H 4N(COMe)} (2-bp = cycloaurated 2-benzylpyridine) shows the presence of puckered metallacyclic rings, with both acetyl substituents positioned below the Au(III) coordination plane. The complex (2-bp)Au{N(COMe)C 6H 4N(COMe)} undergoes ring cleavage in the presence of halide and water, to give the complex (2-bp)Au{N(COMe)C 6H 4NH(COMe)}Cl, which was characterised crystallographically, and shown to contain a monodentate amidate ligand. Biological activity studies of the new auracyclic complexes are also reported, against P388 murine leukaemia cells and a range of bacteria and fungi, with a number of complexes showing high activity.