LAUSR

Cationic monoaryl–PdIV complexes supported by the Klaui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]– (LOEt–) were synthesized, and their reductive elimination was studied. Treatment of trans-[Pd(PPh3)2(Ar)(I)] and [{Pd(η2-ppytBu)Cl}2] [ppytBuH = 2-(4-tert-butylphenyl)pyridine] with [AgLOEt] afforded [Pd(Ar)(PPh3)(η2-LOEt)] [Ar = Ph (1), p-tolyl (2)] and [Pd(η2-ppytBu)(η2-LOEt)] (3), respectively. Chlorination of 1, 2, and 3 with PhICl2 in the presence of NH4PF6 afforded the cationic aryl–PdIV chloride complexes [Pd(Ph)(PPh3)(Cl)(LOEt)](PF6) (4), [Pd(p-tolyl)(PPh3)(Cl)(LOEt)](PF6) (5), and [Pd(η2-ppytBu)(Cl)(LOEt)](PF6) (6), respectively. Complexes 4 and 5 underwent C(sp2)–Cl elimination at 40 °C in acetonitrile to give a PdII–LOEt species and the corresponding chloroarene. On the other hand, the C(sp2)–Cl elimination of 6 occurred at room temperature and afforded a PdII species, presumably [Pd(ClppytBuH)(LOEt)](PF6), which further reacted with PhICl2 to yield [Pd(η2-ClppytBu)Cl(LOEt)](PF6) (7) [ClppytBuH = 2-(4-tert-butyl-2-chlorophenyl)pyridine]. The structures of complexes 1, 4, 6, and 7 were established by X-ray crystallography.