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

The reaction of Re-2(CO)(8)(mu-C6H5)(mu-H), 1 with corannulene (C20H10) yielded the product Re-2(CO)(8)(mu-H)(mu-eta(2)-1,2-C20H9), 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 eta(2)-sigma+pi 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)(mu-H)(mu-eta(2)-1,2-mu-eta(2)-10,11-C20H8)Re-2(CO)(8)(mu-H), 3 (35 % yield), Re-2(CO)(8)(mu-H)(mu-eta(2)-2,1-mu-eta(2)-10,11-C20H8)Re-2(CO)(8)(mu-H), 4 (12 % yield), and Re-2(CO)(8)(mu-H)(mu-eta(2)-1,2-mu-eta(2)-11,10-C20H8)Re-2(CO)(8)(mu-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)(mu-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis.