Ligand-displacement reactions as a powerful route to closo-ruthenacarboranes incorporating bidentate N-donor ligands

A facile ligand-exchange method based on the direct reaction of either three-bridge exo-nido complex [exo-5,6,10-{Cl(Ph₃P)₂Ru}- 5,6,10-(μ-H)₃-10-H-nido-7,8-C₂B₉H₈] or its closo isomer [3,3-(PPh₃)₂-3-Cl-3-H-3,1,2-closo-RuC₂B₉H₁₁] with chelating N,N-donor ligands was employed to synthesize the N,N-diamine-closo-ruthenacarborane complexes [3,3-{κ²-4,4’-R₂-2,2’-(C₅H₃N)₂}-3-PPh₃-closo-3,1,2-RuC₂B₉H₁₁] (R=H, Bu^t) and [3,3-{κ²-phen}-3-PPh₃-closo-3,1,2-RuC₂B₉H₁₁].