Thermal and Photochemical Reactions of a Cationic Rhenocene−Acetonitrile Adduct:  The First C−H Bond Activation by Rhenocene Cation

A cationic rhenocene−acetonitrile adduct [Cp<sub>2</sub>Re(NCMe)](BF<sub>4</sub>) (<b>2</b>) reacted with an excess of benzene and thiophene under UV irradiation to give the C−H bond activation products [Cp<sub>2</sub>Re(H)Ph](BF<sub>4</sub>) (<b>6</b>) and [Cp<sub>2</sub>Re(H)(2-C<sub>4</sub>H<sub>3</sub>S)](BF<sub>4</sub>) (<b>7</b>) in high yields. Deprotonation of <b>6</b> proceeded by treatment with DBU to give phenylrhenocene Cp<sub>2</sub>RePh (<b>8</b>), while protonation of <b>8</b> with HBF<sub>4</sub> regenerated <b>6</b>.