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

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 [Pd-2(mu -Br)(2)(L-)(2)], (6), where L- is [Ph2PCH=C(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.