Synthesis, purification, and structural characterization of the dimethyldiselenoarsinate anion.
A novel arsenic-selenium solution species was synthesized by reacting equimolar sodium selenite and sodium dimethylarsinate with 10 mol equiv of glutathione (pH 7.5) in aqueous solution. The solution species showed a single (77)Se NMR resonance at 112.8 ppm. Size-exclusion chromatography (SEC) using an inductively coupled plasma atomic emission spectrometer (ICP-AES) as the simultaneous arsenic-, selenium-, sulfur-, and carbon-specific detector revealed an arsenic-selenium moiety with an As:Se molar ratio of 1:2. Electrospray ionization mass spectrometry (ESI-MS) of the chromatographically purified compound showed a molecular mass peak at m/z 263 in the negative ion mode. Fragmentation of the parent ion (ESI-MS-MS) produced (CH(3))(2)As(-) and Se(2)(-) fragments. Arsenic and selenium extended X-ray absorption fine structure spectroscopy (EXAFS) of the purified species revealed two As-C interactions at 1.943 A and two As-Se interactions at 2.279 A. On the basis of these results this novel solution species is identified as the dimethyldiselenoarsinate anion.
Gailer
Jürgen
J
Institute for Ecological Chemistry, GSF-National Research Center for Environment and Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany. gailer@gsf.de
George
Graham N
GN
Harris
Hugh H
HH
Pickering
Ingrid J
IJ
Prince
Roger C
RC
Somogyi
Arpad
A
Buttigieg
Gavin A
GA
Glass
Richard S
RS
Denton
M Bonner
MB
D002850:Chromatography, Gel; D004785:Environmental Pollutants / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D012644:Selenium Radioisotopes / Q000737:chemistry; D012996:Solutions
D004785:Environmental Pollutants; D007202:Indicators and Reagents; D012644:Selenium Radioisotopes; D012996:Solutions