Nickel and palladium phosphinimine-imine ligand complexes

The imine (C6H3i-Pr2)NCMe21 was prepared and used to make the phosphine (C6H3i-Pr2)NC(Me)CH2PPh22. Oxidation with the substituted arylazide resulted in the isolation of the phosphinimine-imine species (C6H3i-Pr2)NC(Me)CH2PPh2(NC6H3i-Pr2)3. The ligand 3 forms the neutral Ni-complex NiBr2((C6H3i-Pr2)NC(Me)CH2PPh2(NC6H3i-Pr2))4 while attempts to prepare the analogous Pd species were unsuccessful. Reaction of 3 with n-BuLi produced the Li-salt Li(thf)((C6H3i-Pr2)NC(Me)CHPPh2(NC6H3i-Pr2))5. Subsequent reaction with NiBr2(dme) afforded [Ni((C6H3i-Pr2)NC(Me)CHPPh2(NC6H3i-Pr2))(µ-Br)2Li(thf)2]6. In related syntheses 5 reacted with NiBr2(dme) or (PhCN)2PdCl2 and PPh3 to give the complexes of formulation MX((C6H3i-Pr2)NC(Me)CHPPh2(NC6H3i-Pr2))(PPh3)(X = Br, M = Ni 7; X = Cl, M = Pd 8). The latter complexes 7 and 8 are phosphinimine-N-C bound. Structural studies of 2 and 4-8 are reported. The implications of these studies for the utility of this phosphinimine-imine ligand in olefin polymerization catalysts are considered.