Nickel metallodendrimers as catalyst precursors in the tandem oligomerization of ethylene and Friedel–Crafts alkylation of its olefinic products

Abstract

The synthesis and catalytic activity of nickel metallodendrimers (C1–C6) are reported. The metallodendrimers were synthesized by the coordination of the metal precursors, Ni(OAc)2 and Ni(DME)Br2, to the periphery of salicylaldimine and iminopyridyl modified dendritic ligands, DL1–DL6, based on the generation 1 to generation 3 diaminobutane polypropylene imine (DAB-PPI) dendrimers. The metallodendrimers were tested in the oligomerization of ethylene and were found to be active catalysts. When using this catalyst system, it was found that a tandem process occurred in which ethylene oligomerization was followed by Friedel–Crafts alkylation of the reaction solvent, toluene. The latter process is mediated by the aluminium co-catalyst, EtAlCl2.