Synthesis, X-ray absorption spectroscopy and purification of the seleno-bis ( S-glutathionyl) arsinium anion from selenide, arsenite and glutathione

• Published in: Journal of organometallic chemistry 2002-05, Vol.650 (1), p.108-113
• Main Authors: Gailer, Jürgen, George, Graham N., Pickering, Ingrid J., Buttigieg, Gavin A., Denton, M.Bonner, Glass, Richard S.
• Format: Article
• Language: English
• Subjects: Arsinium anion; S-glutathionyl; Size-exclusion chromatography; X-ray absorption spectroscopy
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(02)01192-0

We report a new synthesis of the seleno-bis ( S-glutathionyl) arsinium anion, [(GS) 2AsSe] −. An aqueous solution of bis-glutathionylarsenous acid, (GS) 2AsOH, prepared from stoichiometric glutathione and arsenite, was reacted in situ with a solution of sodium hydrogen selenide, prepared from elemental selenium and sodium borohydride. Analysis of the arsenic and selenium K-edge X-ray absorption spectra indicated virtually quantitative formation of [(GS) 2AsSe] −, with AsSe and AsS distances of 2.31 and 2.25 Å, respectively, and the concentrated sample allowed a definitive X-ray spectroscopic characterization. Size-exclusion chromatography was used to separate [(GS) 2AsSe] − from residual borate in the reaction mixture. An aqueous solution of bis-glutathionylarsenous acid, (GS) 2AsOH, reacts with a solution of sodium hydrogen selenide to form the seleno-bis ( S-glutathionyl) arsinium anion, [(GS) 2AsSe] −, which was purified by size-exclusion chromatography. Analysis of the arsenic and selenium K-edge X-ray absorption spectra indicated AsSe and AsS distances of 2.31 and 2.25 Å, respectively.