MCl(ligand)]+ Complexes (M = Ni, Pd, Pt) with a P,N,N Terdentate Ligand – Solid State and Solution Structures and Catalytic Activity of the PdII Derivative in the Heck Reaction

Abstract

AbstractNiII, PdII and PtII cationic complexes of the general formula [MCl(PNN)]PF6, where PNN is the terdentate ligand N‐[2‐(diphenylphosphanyl)benzylidene][2‐(2‐pyridyl)ethyl]amine, have been synthesised and fully characterised in solution by NMR spectroscopy. The diamagnetic NiII complex 1 shows fluxionality, which can be attributed to a conformational rearrangement of the two six‐membered chelate rings. On the contrary, the PdII 2 and PtII 3 derivatives are stereochemically rigid on the NMR timescale. The crystal structures of 1 and 2 are reported, which show a planar geometry for both complexes. Complex 2 has been investigated as a precatalyst in the Heck coupling between styrene and bromobenzene. Interestingly, the nature of the solvent has a critical role in determining the yield of the reaction product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)