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

摘要

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) as a ligand was prepared and isolated as a typically yellow-coloured powder of the sodium salt, which showed excellent antimicrobial activity against some bacteria, yeast and moulds. All attempts at crystallization were unsuccessful. This compound was characterized by complete elemental analyses, TG/DTA, FT-IR, various NMR (H-1, C-13 and Ag-109) spectroscopies, and molecular weight determination in aqueous solution by a combination of molmass measurement based on the cryoscopic method with degree of dissociation determination based on the [Na+] measurement in the equilibrium state using an Na+ ion-selective electrode. It was 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 = 4320-5470). Analogues of this anionic Ag-I complex were also obtained as potassium, barium, ammonium, lithium and caesium salts, as well as a free-acid form. [References: 16]