Camphor-based phosphine-carbonyl ligands for Ni catalyzed ethylene oligomerization†
Ni(II) and Pd(II) complexes of camphor-based phosphine-carbonyl ligands containing a biaryl moiety (L1 and L2) are designed, synthesized and characterized. The catalyst Ni1 exhibits high activities (up to 4.5 × 106 g mol Ni−1 h−1) in ethylene oligomerization, generating waxy higher olefins derived from ethylene (Mn 2500–3500, Tm 99–120 °C) in the absence of a co-catalyst. The catalyst Ni2 also exhibits high activity (up to 4.4 × 106 g mol Ni−1 h−1) in ethylene oligomerization, resulting in oily oligomers of ethylene containing a series of lower olefins characterized by GC and GC-MS analyses. No ethylene oligomer over C6 was obtained when using Pd1.