Solution and Solid-State Structures of the Binuclear Zerovalent Palladium Complex [(dippe)Pd]2(μ-dippe) (dippe = 1,2-Bis(diisopropylphosphino)ethane)

The reaction of PdCl2(dippe), where dippe = 1,2-bis(diisopropylphosphino)ethane, with 2 equiv of KBEt3H in toluene generates the binuclear palladium(0) derivative [(dippe)Pd]2(μ-dippe) (4) in 35% yield; alternatively, the reaction of [(η3-C4H7)Pd]2(μ-Cl)2 with MeONa in the presence of 3 equiv of dippe generates 4 as well. Mechanistic studies on the attempted formation of mixed binuclear complexes are reported as well as the use of 4 as a catalyst for the reductive dechlorination of chloroarenes. Analysis of the second-order [AB2]2 spin system was accomplished by iteration of the 202.47 MHz 31P{1H} NMR spectrum of 4; the solution structure and the solid-state structures are found to be very nearly identical.