Synthesis and Crystal Structure of Palladium(0) and Arylpalladium(II) Bromide Complexes of CataCXium A

Abstract

Diphosphine palladium(0) (1) and arylpalladium(II) bromide complexes (2a−d) of di-1-adamantyl-n-butylphosphine (CataCXium A) have been synthesized. The PdL2 complex 1 takes a remarkable eclipsed conformation of the substituents along the P−Pd−P direction. NMR and X-ray studies of 2a showed its dimeric structure with the n-butyl groups of the coordinated phosphine ligands lying nearly parallel to the planes of the aromatic rings, which results in an anomalous 1H NMR upfield shift of the n-butyl protons caused by the aromatic ring current effect.