Multiple Aromatic C-H Bond Activations by an Unsaturated Dirhenium Carbonyl Complex

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

The reaction of Re₂ (CO)₈ (μ-C₆ H₅ )(μ-H), 1 with corannulene (C₂₀ H₁₀ ) yielded the product Re₂ (CO)₈ (μ-H)(μ-η² -1,2-C₂₀ H₉ ), 2 (65 % yield) containing a Re₂ 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 η² -σ+π coordination to the Re₂ (CO)₈ grouping. Compound 2 reacts with a second equivalent of 1 to yield three isomeric doubly metalated corannulene products: Re₂ (CO)₈ (μ-H)(μ-η² -1,2-μ-η² -10,11-C₂₀ H₈ )Re₂ (CO)₈ (μ-H), 3 (35 % yield), Re₂ (CO)₈ (μ-H)(μ-η² -2,1-μ-η² -10,11-C₂₀ H₈ )Re₂ (CO)₈ (μ-H), 4 (12 % yield), and Re₂ (CO)₈ (μ-H)(μ-η² -1,2-μ-η² -11,10-C₂₀ H₈ )Re₂ (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 Re₂ (CO)₈ (μ-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis.

Multiple activations of CH bonds in arenes and heteroarenes

Re₂(CO)₈(μ-C₆H₅)(μ-H) reacts with anthracene four times to yield the quadruply CH activated complex [Re₂(CO)₈(μ-H)]₄(μ-η²-1,2-μ-η²-3,4-μ-η²-5,6-μ-η²-7,8-C₁₄H₆).