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

Abstract

We report a new synthesis of the seleno-bis (S-glutathionyl) arsinium anion, [(GS)(2)AsSe]. An aqueous solution of bis-glutathionylarsenous acid. (GS)(2)As-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)(2)AsSe](-), with As-Se and As-S distances of 2.31 and 2.25 Angstrom, respectively, and the concentrated sample allowed a definitive X-ray spectroscopic characterization. Size-exclusion chromatography was used to separate [(GS)(2)AsSe] from residual borate in the reaction mixture