An arachno-metallacarbaborane containing intermolecular hydrogen bridges. Crystal and molecular structure of bis-[11-triphenylphosphine-11-argenta-5,6-dicarbaundecaborane(11)]

Abstract

The metallacarbaboranes PPh₃AuC₂B₈H₁₁, PPh₃CuC₂B₈H₁₁. and (PPh₃)₂AgC₂B₈H₁₁ have been prepared and (PPh₃)₂AgC₂B₈H₁₁ suffers a partial loss of triphenylphosphine on recrystallisation, to give ‘PPh₃AgC₂B₈H₁₁’; this last compound is shown from i.r. and X-ray data to have a dimeric structure comprising two enantiomeric arachno-AgC₂B₈ cages, linked by a pair of Ag–H–B bridges derived from terminal B–H groups, and analogous, though monomeric, arachno-structures are suggested for PPh₃AuC₂B₈H₁₁ and (PPh₃)₂AgC₂B₈H₁₁.