New Routes to η1- and (η3↔η5)-Indenylpalladium Complexes: Synthesis, Characterization, and Reactivities

The dimer {(η3-Ind)Pd(μ-Cl)}2 (6) reacts with t-BuNC to give the dimeric species {(η1-Ind)(t-BuNC)Pd(μ-Cl)}2 (10), whereas reaction with PR3 gives the complexes (η-Ind)Pd(PR3)Cl (R = Ph (4), Cy (7), Me (8), OMe (9)). Complexes 4 and (1-Me-Ind)Pd(PPh3)Cl (5) can also be prepared by reacting (PhCN)2PdCl2 with LiInd and PPh3. The structural characterization of complexes 47, 9, and 10 by 1H and 13C 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 4, 6, and 7 react with PhSiH3 in the absence of cocatalysts, whereas reaction with ethylene requires the presence of excess MAO to give polyethylene.