Anthracene and Pyrene Ruthenacarboranes

Dehalogenation of the anion [3,3-(PPh₃)₂-3-Cl-closo-3,1,2-RuC₂B₉H₁₁]⁻ in the presence of toluene, anthracene and pyrene affords the new ruthenacarborane species [3-(C₆H₅Me)-closo-3,1,2-RuC₂B₉H₁₁] (1), [3-C₁₄H₁₀-closo-3,1,2-RuC₂B₉H₁₁] (2) and [3-C₁₆H₁₀-closo-3,1,2-RuC₂B₉H₁₁] (3), respectively. Compounds 2 and 3 are the first examples of anthracene and pyrene metallacarboranes. In 2 and 3 the orientation of the polycyclic aromatic hydrocarbon (PAH) with respect to the metallacarborane cage is controlled by the relatively weak trans influences of the cage C atoms and the ligating ring junction C atoms of the PAH compared to the relatively strong trans influences of the facial B atoms of the carborane and the ligating non-junction atoms of the PAH. Thus is demonstrated a pronounced structural anthracene effect and structural pyrene effect, to complement established structural indenyl and structural naphthalene effects in metallacarborane chemistry.