Hydride generation activity of arsenosugars and thioarsenicals.
The major arsenosugar compounds have been reported to be hydride-generation-active, however to a lesser extent in comparison with the inorganic arsenicals. We report here for the first time the identity and quantity of the volatile arsenicals generated by As-sugar-SO(3), As-sugar-SO(4), dimethylarsinoyl acetic acid and dimethylarsinoyl ethanol. Only one major volatile compound was identified for all four compounds studied: dimethylarsine. This means that the As-C bond to the longer carbon chain was cleaved during the hydride-generation process. Theoretical calculations at the RHF/6-31G(d,p) ab initio level confirm that this As-C bond is much weaker than the As-CH(3) bonds. Furthermore, it was revealed that the sulphur analogue of dimethylarsinic acid (DMAS ) is hydride-generation-active at pH 7 in contrast to dimethylarsinic acid, despite the fact that arsenic is also pentavalent. This has been substantiated by the calculation of the change in susceptibility of the arsenic towards nucleophilic attack when oxygen is replaced by sulphur. Hence, DMAS can easily be mistaken for a trivalent arsenic species.
Regmi
Rajendra
R
Department of Chemistry, College of Physical Sciences, University of Aberdeen, Old Aberdeen, AB24 3UE, UK.
Milne
Bruce F
BF
Feldmann
Jörg
J
D000085:Acetates / Q000032:analysis / Q000737:chemistry; D000465:Algorithms; D001149:Arsenates / Q000032:analysis* / Q000737:chemistry; D001151:Arsenic / Q000737:chemistry; D001152:Arsenicals / Q000032:analysis* / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000031:analogs & derivatives / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D009005:Monosaccharides / Q000032:analysis* / Q000737:chemistry; D009942:Organometallic Compounds / Q000032:analysis* / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry; D013997:Time Factors; D014835:Volatilization
D000085:Acetates; D001149:Arsenates; D001152:Arsenicals; D009005:Monosaccharides; D009942:Organometallic Compounds; D013431:Sulfates; D013438:Sulfhydryl Compounds; D013440:Sulfides; C449161:arsenosugar; C477455:dimethylarsinoylacetic acid; D000431:Ethanol; C062856:dimethylarsine; D002244:Carbon; D001151:Arsenic