(Ferrocenylpyrazolyl)nickel(II)-catalysed ethylene oligomerisation

Collins Obuah, Johan H.L. Jordaan, James Darkwa

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15 Citations (Scopus)


Compounds L1-L6 (3-ferrocenylpyrazole (L1), 3-ferrocenyl-5-methylpyrazole (L2), 3-ferrocenylpyrazolyl-methylenepyridine (L3), 3-ferrocenyl-5-pyrazolyl-methylenepyridine (L4), 3-ferrocenylpyrazolyl-ethylamine (L5) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L6)) reacted with [NiBr2(DME)] or [NiCl2·6H2O] to give the mononuclear nickel complexes [NiBr21-L1)2] (1), [NiBr21-L2)2] (2), [NiBr22-L3)] (3), [NiBr22-L4)] (4), [NiBr22-L5)] (5), [NiBr22-L6)] (6), [NiCl22-L3)] (7) and [NiCl22-L4)] (8). Because these nickel complexes are paramagnetic, they were characterised by a combination of IR spectroscopy, mass spectrometry, elemental analysis and, in selected cases, single crystal X-ray crystallography. Activation of complexes 1-8 with EtAlCl2 in chlorobenzene produced active species that catalysed ethylene oligomerization to butenes and C16-C64 olefins, showing a non-Schulz-Flory distribution of products. Complexes 2 and 3 were the most active (1989 kg of ethylene oligomer per mol of Ni per h and 1776 kg of ethylene oligomer per mol of Ni per h, respectively) and, in toluene, produced isomers of butene and small amounts of butyltoluenes via Friedel-Crafts alkylation of toluene by the butenes.

Original languageEnglish
Pages (from-to)4814-4823
Number of pages10
JournalCatalysis Science and Technology
Issue number13
Publication statusPublished - 2016

ASJC Scopus subject areas

  • Catalysis


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