Multiple C−H Bond Activations in Corannulene by a Dirhenium Complex

The reaction of Re ₂ (CO) ₈ (μ-C ₆ H ₅ )(μ-H), 1 with corannulene (C ₂₀ H ₁₀ ) yielded the product Re ₂ (CO) ₈ (μ-H)(μ-η ² -1,2-C ₂₀ H ₉ ), 2 (65 % yield) containing a Re ₂ metalated corannulene ligand formed by loss of benzene from 1 and the activation of one of the CH bonds of the nonplanar corannulene molecule by an oxidative-addition to 1. The corannulenyl ligand has adopted a bridging η ² -σ+π coordination to the Re ₂ (CO) ₈ grouping. Compound 2 reacts with a second equivalent of 1 to yield three isomeric doubly metalated corannulene products: Re ₂ (CO) ₈ (μ-H)(μ-η ² -1,2-μ-η ² -10,11-C ₂₀ H ₈ )Re ₂ (CO) ₈ (μ-H), 3 (35 % yield), Re ₂ (CO) ₈ (μ-H)(μ-η ² -2,1-μ-η ² -10,11-C ₂₀ H ₈ )Re ₂ (CO) ₈ (μ-H), 4 (12 % yield), and Re ₂ (CO) ₈ (μ-H)(μ-η ² -1,2-μ-η ² -11,10-C ₂₀ H ₈ )Re ₂ (CO) ₈ (μ-H), 5 (12 % yield), by a second CH activation on a second rim double bond on the corannulene molecule. The isomers differ by the relative orientations of the coordinated Re ₂ (CO) ₈ (μ-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis.