Characterization by electrospray ionization (ESI) mass spectrometry of an oligomeric, anionic thiomalato-silver(I) complex showing biological activity

The tetrameric anionic species {Na3[Ag(Htma)]4-}–(m/z= 1092.8; H3tma = thiomalic acid) is detected by negative-ion electrospray ionization (ESI) mass spectrometry as a stable constituent unit derived from an aqueous solution of the oligomeric thiomalato-silver(I) complex, recently isolated and characterized as {Na[Ag(Htma)]·0.5H2O}n(n= 24–34)1, which displays antimicrobial activity against selected bacteria, yeast and moulds.