Gold complexes with thiosemicarbazones: Reactions of bi- And tridentate thiosemicarbazones with dichloro2-(dimethylaminomethylphenyl-CilgoldCm), [Au(damp-C1A)Cl2]

Abstract

Dichloro[2-(A,A-dimethylaminomethyl)phenyl-C1,A]gold(iii), [Au(damp-C,A)Cl2] (1), reacts with salicylaldchyde thiosemicarbazone (H2saltsc), vanilline thiosemicarbäzone (Hvantsc), N-methylpyrrole aldehyde thiosemicarbazone (Hmepyrtsc), pyridoxal methylthiosemicarbazone (H2pydoxmetsc), 2-diphenylphosphinobenzaldehyde thiosemicarbazone (HPtsc) or variously substituted acetylpyridine thiosemicarbazones (HapRtsc; R = H, Me, Ph) with cleavage of the Au-N bond and protonation of the dimethylamino group. Compounds of general formulae [Au(Hdamp-C1)CI(L)f (L = Hsaltsc-, vantsc-, mepyrtsc1), [Au(Hdamp-C1)Cl(L)]2+ (L = H2pydoxmetsc) or [Au(Hdamp-C1)(L)]2+ (L = Ptsc-, apRtsc-, R = H, Me, Ph) have been isolated and characterized. The presence of the (T-bonded 2-(dimethylaminomethyl)phenyl ligand is mandatory to prevent reduction of the gold(in) centre. The crystal structures of [Au(Hdanip-C1)CI(HsaItsc)](PF6) (3a), [Au(Hdamp-C')Cl(mepyrtsc)]Cl (3c), [Au(Hdamp-C1)-CI(H2pydo.xtnetsc)]Cl2-MeOH (4), [Au(Hdamp-C1)(apPhtsc)]Cl2-2 MeOH (5c) and [Au(Hdamp-C')(Ptsc)]Cl2-1.5MeOH (6) have been elucidated, showing the gold atoms in distorted square-planar co-ordination environments. The potentially O,N,S-tridentate ligands H2saltsc and H2pydoxmetsc co-ordinate in a bidentate fashion and do not incorporate the OH groups in the chelating framework, whereas HapRtsc or HPtsc co-ordinate in a tridentate manner. Generally, one or more hydrogen atoms of the heterocyclic ligands and/or the NMe2H+ group form hydrogen bridges in the solid state structures. The preliminary results of antiproliferation tests on tumor cells demonstrate the considerable cytotoxicity of these new gold complexes. © The Royal Society of Chemistry 2000.