The Lewis-base behavior of Bunsen’s cacodyl disulfide,Me 2 As(S)–S–AsMe 2,toward molecular halides of group 13

Abstract

Molecular halides of group 13 in chloroform solutions interact but do not split Bunsen’s cacodyl disulfide, Me₂As(S)–S–AsMe₂. With BF₃·Et₂O cacodyl disulfide gives an equilibrated mixture of Me₂As(S)–S–AsMe₂ and Me₂As–SS–AsMe₂, whereas AlCl₃ causes complete isomerization to Me₂As–SS–AsMe₂ which is stabilized by complexation to AlCl₃. GaCl₃ and InCl₃ do not isomerize Me₂As(S)–S–AsMe₂ but only bind to it. Thallium(III) acetate, splits Me₂As(S)–S–AsMe₂ giving initially the unstable thallium(III) complex, (Me₂AsS₂)₃Tl, which is spontaneously converted to Me₂AsS₂Tl. The electrons for the reduction Tl(III)→Tl(I) most likely come from two of the –S:⁻ sulfur anions bound to the initially formed (Me₂AsS₂)₃Tl.