Thermolytic reaction of 1,4-diisopropenylbenzene with [Ru3(CO)12]: an arene ligand as a template for cluster formation

Abstract

The reaction of [Ru₃(CO)₁₂] with 1,4-diisopropenylbenzene in refluxing octane led to the isolation of a series of clusters with nuclearities from 2 to 7: [Ru₄(CO)₁₀(C₁₂H₁₄)]1, [Ru₃(CO)₈(C₁₂H₁₂)]2, [Ru₆H(CO)₁₅(C₁₂H₁₁)]3, [Ru₆H(CO)₁₅(C₁₂H₁₃)]4, [Ru₂(CO)₆(C₁₂H₁₂)]5, [Ru₇C(CO)₁₆(C₁₂H₁₂)]6, [Ru₃H(CO)₉(C₁₂H₁₁)]7, [Ru₅H(CO)₁₄(C₁₂H₁₁)]8 and [Ru₆C(CO)₁₅(C₁₁H₁₀)]9. The molecular structures of 1 and the three metallacycle compounds 2–4 have been determined by X-ray crystallography. The hexaruthenium species 3 and 4 represent a new category of arene cluster. The six ruthenium atoms describe an edge-bridged tetrahedron with a ruthenium spike bound to the edge-bridging atom. The arene ligand acts as an eleven-electron donor via both σ and π bonds. The pathway of the reaction has been established and provides evidence for ligand-moderated modular cluster build-up in which the ligand acts as a template.