New Routes to η<sup>1</sup>- and (η<sup>3</sup>↔η<sup>5</sup>)-Indenylpalladium Complexes: Synthesis, Characterization, and Reactivities

The dimer {(η<sup>3</sup>-Ind)Pd(μ-Cl)}<sub>2</sub> (<b>6</b>) reacts with <i>t</i>-BuNC to give the dimeric species {(η<sup>1</sup>-Ind)(<i>t</i>-BuNC)Pd(μ-Cl)}<sub>2</sub> (<b>10</b>), whereas reaction with PR<sub>3</sub> gives the complexes (η-Ind)Pd(PR<sub>3</sub>)Cl (R = Ph (<b>4</b>), Cy (<b>7</b>), Me (<b>8</b>), OMe (<b>9</b>)). Complexes <b>4</b> and (1-Me-Ind)Pd(PPh<sub>3</sub>)Cl (<b>5</b>) can also be prepared by reacting (PhCN)<sub>2</sub>PdCl<sub>2</sub> with LiInd and PPh<sub>3</sub>. The structural characterization of complexes <b>4</b>−<b>7</b>, <b>9</b>, and <b>10</b> by <sup>1</sup>H and <sup>13</sup>C NMR spectroscopy and single-crystal X-ray diffraction studies has allowed an analysis of the indenyl ligand's mode of coordination, both in the solid-state and in solution. Compounds <b>4</b>, <b>6</b>, and <b>7</b> react with PhSiH<sub>3</sub> in the absence of cocatalysts, whereas reaction with ethylene requires the presence of excess MAO to give polyethylene.