Palladium(ii) complexes with the bidentate iminophosphine ligand [Ph2PCH2C(Ph)N(2,6-Me2C6H3)]

Abstract

A new iminophosphine ligand, [Ph₂PCH₂C(Ph)N(2,6-Me₂C₆H₃)] (HL), and the complexes [PdX₂(HL)], where X = Cl (1) and Br (2), [PdMeX(HL)], X = Cl (3) and Br (4), and [PdMe₂(HL)] (5) have been prepared and characterised. Reaction of 2 with MeLi or KH leads to deprotonation of the neutral ligand to give [Pd₂(μ-Br)₂(L⁻)₂], (6), where L⁻ is [Ph₂PCHC(Ph)N(2,6-Me₂C₆H₃)]⁻. Similarly, reaction of 3 with KH and triphenylphosphine affords the neutral complex [PdMe(PPh₃)(L⁻)] (7). Insertion of CO into the Pd–Me bond has been investigated, as well as the catalytic properties of [PdClMe(HL)] towards CO/ethylene copolymerisation. The crystal structures of HL, 1–3 and 5–7 have been determined.