SYNTHESIS AND CHARACTERIZATION OF OLIGOMERIC, ANIONIC THIOMALATO-SILVER(I) COMPLEXES WITH BIOLOGICAL-ACTIVITIES

A water-soluble, thermally and light-stable, anionic Ag-I complex with a trianion of thiomalic acid, TMA(3-) (H(3)TMA = HOOCCH(SH)CH2COOH) a s a ligand was prepared and isolated as a typically yellow-coloured po wder of the sodium salt, which showed excellent antimicrobial activity against some bacteria, yeast and moulds. All attempts at crystallizat ion were unsuccessful. This compound was characterized by complete ele mental analyses, TG/DTA, FT-IR, various NMR (H-1, C-13 and Ag-109) spe ctroscopies, and molecular weight determination in aqueous solution by a combination of molmass measurement based on the cryoscopic method w ith degree of dissociation determination based on the [Na+] measuremen t in the equilibrium state using an Na+ ion-selective electrode. It wa s shown that this complex was not a monomeric species, but an oligomer with a formula of {NaH [Ag(TMA)].0.5H(2)O}(n) (n = 15-19; MW = 4320-5 470). Analogues of this anionic Ag-I complex were also obtained as pot assium, barium, ammonium, lithium and caesium salts, as well as a free -acid form.