Pyrazole and pyrazolylethylamine nickel(II) and palladium(II) complexes as catalysts for olefin oligomerization and Friedel-Crafts reactions

• Main Author: Moeti, Lerato Petunia
• Published: 2015
• Subjects: Palladium catalysts; Pyrazoles; Palladium compounds - Synthesis; Nickel catalysts; Alkenes; Nickel compounds - Synthesis
• Online Access: http://hdl.handle.net/10210/13834

M.Sc. (Chemistry) === This study deals with the synthesis of nitrogen-donor pyrazole- and pyrazolylethylamine compounds, their reactions with palladium(II) and nickel(II) precursors to form complexes and the applications of theses palladium(II) and nickel(II) complexes as catalysts for ethylene oligomerization reactions and reactions of higher α-olefins in Friedel-Crafts alkylation of aromatic solvents. A series of ligands, 3,5-di-tert-butyl-1H-pyrazole (L3), 3,5-diphenyl-1H-pyrazole (L4), 5-phenyl-3-(trifluoromethyl)-1H-pyrazole (L5) were synthesized using appropriate amounts of diketones and hydrazine hydrate; while ligands, 2-(1H-pyrazol-1-yl)ethylamine (L6), 2-(3,5-dimethyl-1H-pyrazol-1-yl)-ethylamine (L7), 2-(3,5-di-tert-butyl-1H-pyrazol-1-yl)-ethylamine (L8), 2-(3,5-diphenyl-1H-pyrazol-1-yl)-ethylamine (L9) and 2-(5-phenyl-3-(trifluoromethyl)-1H-pyrazol-1-yl)ethylamine (L10) were prepared via the N sp3 alkylation of the corresponding pyrazoles with bromoethylamine Reactions of L1-L5 with [PdCl2(CNMe)2] formed five complexes of general formula [PdCl2 (L)2] {L = L1 (2.1), L2 (2.2), L3 (2.3), L4 (2.4) and L5 (2.5)}. Similarly [NiBr2(DME)] formed five complexes of general formula [NiBr2(L)2] {L = L1(2.6), L2 (2.7), L3 (2.8), L4 (2.9) and L5 (2.10)}. Complexes 2.1-2.10 were synthesized in a 2:1 mole ratio of ligand and metal precursor. Reactions of L6-L10 with [PdCl2(MeCN)2] yielded complexes 3.1-3.5 respectively. Ligands L6-L10 were also complexed with NiCl2.6H2O to give complex 3.6 while [NiCl2(DME)] and [NiBr2(DME)] gave complexes 3.7-3.8 and 3.9-3.13 respectively...