Iron(III) complexes with meta-substituted bis(arylimino)pyridine ligands: Catalyst precursors for the selective oligomerization of ethylene

Bis(arylimino)pyridine iron(III) complexes containing meta-halogen substituents at the iminophenyl rings were synthesized and characterized. In contrast to iron(II) complexes, the presence of at least one ortho-substituent at the iminophenyl rings is not obligative for catalytic activities of these iron(III) complexes. After activation with methylaluminoxane (MAO), these catalysts oligomerize ethylene to give also internal and branched olefins besides the expected linear α-olefins. The widths of the resulting molecular weight distributions and the degrees of isomerization of the resulting oligomers strongly depend on the substitution pattern at the ligand frameworks.

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► Synthesis of highly selective bis(arylimino)pyridine iron(III) catalysts for the oligomerization of ethylene to short chain α-olefins.
► Detailed description of the influence of the substitution patterns of the ligand backbones on the catalytic behavior.
► Surprising production of internal and branched olefins: isomerization, copolymerization and unusual reaction pathways.