Synthesis, Molecular Structure, and Reactivity of Indenylrhodium Complexes Containing Diphenylcarbene as Ligand<sup>†</sup>

(η<sup>5</sup>-Indenyl)rhodium(I) complexes of the general composition [(η<sup>5</sup>-C<sub>9</sub>H<sub>7</sub>)Rh(CPh<sub>2</sub>)(L)] (L = Sb<i>i</i>Pr<sub>3</sub> (<b>6</b>), P<i>i</i>Pr<sub>3</sub> (<b>7</b>), PPh<sub>3</sub> (<b>8</b>), P<i>i</i>PrPh<sub>2</sub> (<b>9</b>), P<i>i</i>Pr<sub>2</sub>Ph (<b>10</b>)) were prepared from the square-planar precursors <i>trans</i>-[RhCl(CPh<sub>2</sub>)(L)<sub>2</sub>] (<b>1</b>−<b>5</b>) and C<sub>9</sub>H<sub>7</sub>K in THF. Treatment of <b>6</b>−<b>10</b> with carbon monoxide resulted in an unusual migratory insertion of the carbene ligand into one of the C−H bonds of the five-membered ring of the indenyl unit to give the compounds [{η<sup>5</sup>-C<sub>9</sub>H<sub>6</sub>(CHPh<sub>2</sub>)}Rh(CO)(L)] (<b>12</b>−<b>16</b>) in 78−87% yield. The X-ray crystal structure analyses of <b>6</b> and <b>13</b> revealed that in both complexes the slip distortion from a η<sup>5</sup> to a η<sup>3</sup> coordination mode of the indenyl ligand is nearly the same, independent of the bulky CHPh<sub>2</sub> group in the ring-substituted species.