The instability of coordinated As(III) thiolates, As(SPh)3 and R-As(SPh)2 (R = Me, 2-nitrophenyl), to heavy metal cations

The coordination ability of As(III) thiolates, having two kinds of Lewis base atoms [As(III) and S(II)], towards heavy metal salts was virtually not studied. We have found that As(SPh)3 (A), Me-As(SPh)2 (B), and 2-O2N-PhS-As(SPh)2 (C) with the acetates M(OAc)2 (M = Cd, Pb, Hg) gave the metal thiophenolate M(SPh)2 (except in the case of B and Cd(OAc)2 which gave PhS-Cd-OAc·Cd(SPh)2) and with HgCl2 gave (PhS-Hg-Cl)2·HgCl2. The thiophenolates of cadmium and lead(II) were not reactive towards their corresponding acetates and chlorides, while Hg(SPh)2 gave PhS-Hg-OAc and (PhS-Hg-Cl)2·HgCl2. Likely mechanisms for these reactions are suggested.