The reaction of British Anti-Lewisite (dimercaprol) with As(III),Sb(III),and Bi(III) oxides and salts

The α,β-dithiol 2,3-dimercapto-1-propanol (dimercaprol or British Anti-Lewisite, BAL) reacts with AsCl₃, in a 1:1 molar ratio, giving the expected cyclic adduct 1 but with As₂O₃ and with AsCl₃, in 2:3 As/BAL molar ratios, gave gums composed of many compounds. BAL reacts with Sb₂O₃ in DMSO but the products could not be isolated. With SbCl₃ two products 2 and 3 have been isolated in 1:1 and 2:3 Sb/BAL molar ratios. Bi₂O₃ in 1:1 and 2:3 molar ratios gave compounds 4 and 5. However, BiCl₃ and Bi(NO₃)₃·5H₂O in either 1:1 or 2:3 stoichiometries gave compounds 6 and 7, respectively, indicating that the >Bi-Cl and >Bi(NO₃) bonds were not reactive towards excess BAL. The ¹H and ¹³C NMR spectra of the Sb(III) and Bi(III) complexes in DMSO-d₆ revealed broad signals attributed to the quadrupole relaxation of Sb and Bi nuclei. No relaxation was observed for the arsenic complex 1 in CD₃OD. Other properties of the complexes are presented and discussed.