Synthesis and evaluation of ferrocenylpyrazolyl and ferrocenylpyrazolyl-phosphine palladium and nickel complexes as ethylene oligomerization catalysts

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dc.contributor.advisor Prof. J. Darkwa en_US
dc.contributor.author Van der Westhuizen, Arnoux
dc.date.accessioned 2012-06-07T09:59:17Z
dc.date.available 2012-06-07T09:59:17Z
dc.date.issued 2012-06-07
dc.date.submitted 2011-10-04
dc.identifier.uri http://hdl.handle.net/10210/5035
dc.description M.Sc. en_US
dc.description.abstract Several bis[1-ferrocenyl(ethyl)pyrazolyl palladium dichloro (complexes 1 and 3) and palladium chloromethyl complexes (complexes 2 and 4) have been synthesized by the reactions of 1- ferrocenyl(ethyl)-1N-pyrazole and 1-ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole with [PdCl2(NCMe)2] and [PdClMe(cod)] respectively. Furthermore, a library of phosphorus^nitrogen (P^N) ferrocenyl(ethyl)-amine and -pyrazolyl ligands have been successfully synthesized using the well known Ugi amine (compound 5) as intermediate. 1- [2-{diphenylphosphino}ferrocenyl](ethyl)amine and 1-[{2-diphenylphosphino}ferrocenyl](ethyl)- pyrazolyl Ni(II) and Pd(II) complexes were synthesized by reacting 1-[2- {diphenylphosphino}ferrocenyl](ethyl)dimethylamine, 1-[2-{diphenylphosphino}ferrocenyl](ethyl)- 1N-pyrazole and 1-[2-{diphenylphosphino}ferrocenyl](ethyl)-1N-(3,5-dimethyl)pyrazole with [NiCl2•6H2O] (compounds 12 and 16), [NiBr2(DME)] (compounds 13, 17 and 19), [PdCl2(NCMe)2] (compounds 10, 14, and 18) and [PdClMe(cod)] (compounds 11 and 15), respectively. 1-[2- {Diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole (compound 9) was synthesized by two distinct methodologies. In one method, 1-ferrocenyl(ethyl)dimethylamine was converted to 1-[2- {diphenylphosphino}ferrocenyl](ethyl)dimethylamine before it was subsequently reacted with 3,5- dimethylpyrazole to produce 1-[2-{diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole. In the other method, 1-ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole was converted to 1-[2- {diphenylphosphino}ferrocenyl](ethyl)-1N-(3,5-dimethyl)pyrazole before the reaction with 3,5- dimethylpyrazole, producing 1-[2-{diphenylphosphino}ferrocenyl(ethyl)-1N-(3,5-dimethyl)pyrazole. These compounds synthesized via different methods as well as their palladium dichloro complexes show different structures in solution, but solid state structural analysis agrees on the same structure. The structural difference in solution is contributed to the high degree of flexibility at the stereogenic centre of the complex. The Ni(II) ferrocenyl phosphine complexes 12, 13, 16, 17 and 19 exist in equilibrium between diamagnetic square planar form and paramagnetic tetrahedral form. The tetrahedral geometry is xvi favoured over the square planar geometry, purely on steric grounds, but the square planar geometry occurs with d8 complexes because of the more favourable electronic situation of the complex. Activation of these P^N palladium and nickel ferrocenyl- amine and -pyrazolyl pre-catalysts 10, 12, 13, 14, 16, 17, 18a and 19 with EtAlCl2 results in the oligomerization of ethylene to C4 and C6 alkenes, followed by subsequent Friedel-Crafts alkylation of the toluene solvent. Moderate catalytic activities of up to 659 kg of alkylated toluene products.mol-1 Ni. h-1 were observed for catalyst 13 at 20 bar ethylene pressure. In general, the Ni(II) pre-catalysts were more active than the Pd(II) precatalyst. en_US
dc.language.iso en en_US
dc.subject Palladium compounds en_US
dc.subject Nickel compounds en_US
dc.title Synthesis and evaluation of ferrocenylpyrazolyl and ferrocenylpyrazolyl-phosphine palladium and nickel complexes as ethylene oligomerization catalysts en_US
dc.type Thesis en_US

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