MERCURY COORDINATION TO EXO-DITHIO-7,8-DICARBA-NIDO-UNDECABORATE DERIVATIVES

Ligands incorporating two sulphur atoms directly connected to the carb on atoms of the unit 7,8-dicarba-nido-undecarborate (1-) have been sho wn to coordinate via the sulfur groups, and for Ru(II) or Rh(III) addi tional participation of the unit B(3)-H in the coordination is observe d. Mercury (II) is an exception, and Hg-C2B3 (metal-to-open-face bondi ng) has been demonstrated regardless of the presence of the two sulfur atoms. This coordination has been proved unambiguously by the crystal structure of [Hg(L(s2c5))(PPh3)] where L(s2c5)(2-) = {7,8-mu-(SCH2S)- 7,8-C2B9H9}2-.