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

摘要

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)Br_2, 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, EtAlCl_2.