Proton Lability in Highly Hindered Dinuclear Palladium(I) μ-Phosphido−Secondary Phosphine Complexes. Crystal Structures of [Pd2(μ-PBut2)(PCy2H)3(CO)]BF4 and [Pd2(μ-PBut2)(PCy2H)2(μ,η2,η2-isoprene)]BF4

Abstract

The reactions of the dinuclear cationic complexes [Pd2(μ-PBut2)(PR3)4]+ (PR3 = PCy2H, PMe3) with CO or isoprene proceed with substitution of one or two phosphine ligands giving the corresponding [Pd2(μ-PBut2)(PR3)3(CO)]+ and [Pd2(μ-PBut2) (μ,η2,η2-isoprene)(PR3)2]+ cations. [Pd2(μ-PBut2)(PCy2H)3(CO)]+ equilibrates in solution to a mixture of monocarbonyl derivatives arising from bridging phosphido/terminal phosphine interchange. The complexes were characterized by multinuclear 1-D and 2-D NMR spectroscopy. The crystal and molecular structures of [Pd2(μ-PBut2)(PCy2H)3(CO)]BF4 and [Pd2(μ-PBut2)(PCy2H)2(μ,η2,η2-isoprene)]CF3SO3 were solved by single-crystal X-ray diffraction studies.