Synthesis and reactivities of neutral and cationic indenyl-palladium complexes

The complexes [(1-R-Ind)Pd(PPh3)Me] (R = H (3), Me (4)), [(1-R-Ind)Pd(PPh3)(2)]BF4 (R = H (5[BF4]), Me (6)), and [(1-R-Ind)Pd(PPh3)(OSO2CF3)] (R = H (7), Me (8)) have been prepared by reacting their corresponding Pd-Cl derivatives with MeMgCl, AgBF4/PPh3, and AgOTf, respectively. These complexes have been characterized by NMR spectroscopy and, in the case of 3, 5[BF4], 6 and 7, by X-ray crystallography. The triflate moiety in complexes 7 and 8 is displaced readily by various ligands to give [(1-R-Ind)Pd(PPh3)L][OTf] (L = PPh3 (5[OTf]), PMe3 (9), CH3CN (10), PhCN (11), t-BuNC (12)). Reactions of 7 or 8 with various olefins result in isomerization (1-hexene), dimerization and/or trimerization (ethylene, styrene, and p-fluorostyrene), oligomerization (p-amino- and p-methylstyrene), or polymerization (p-methoxystyrene). Compounds 1-8 promote the addition of HSiCl3 to styrene and phenylacetylene.