Chemical and biological reactions of diacetato[2-(dimethylaminomethyl)-phenyl]gold(III), [Au(O2CMe)2(dmamp)]

Abstract

The gold(III) complex [Au(O₂CMe)₂(dmamp)][dmamp = 2-(dimethylaminomethyl)phenyl] is hydrolysed in wholly or partially aqueous solution. One acetate ligand, presumed to be that trans to the Au–C bond, exchanged with a water molecule rapidly on the NMR time-scale. At high concentrations of water a further hydrolysis step was also discernible, which involved the second acetate group while, in aged solutions, small amounts of a third species, possibly the second isomer of [Au(O₂CMe)(dmamp)(H₂O)]⁺, was formed. The reaction of aqueous or dimethyl sulfoxide solutions of the gold(III) complex with various biological ligands was followed by NMR spectroscopy and a range of reactivities was found: caffeine and adenosine showed no reaction, L-cysteine, glutathione and adenine reacted quantitatively and guanosine and inosine showed partial reaction. In in vitro biological tests for antibacterial activity, [Au(O₂CMe)₂(dmamp)] exhibited a potentially useful selectivity.