Trapping the Short-Chain Odd Carbon Number Olefins Using Nickel(II)-catalyzed Tandem Ethylene Oligomerization and Friedel-Crafts Alkylation of Toluene

Nickel(II) complexes with pyrazole-based ligands are widely employed in catalysis of ethyleneoligomerization and subsequent Friedel-Crafts alkylation of toluene. We have prepared ten newnickel(II) dibromide complexes with various substituted bis(azolyl)methanes. They have beencharacterized using 1H NMR, IR, MALDI-TOF and elemental analysis. The structures of threecomplexes have been unambiguously established using X-ray diffraction. It was found that thesecomplexes in the presence of Et2AlCl or Et3Al2Cl3 are active both in ethylene oligomerization andFriedel-Crafts alkylation processes (activity up to 3720 kgoligomer·mol[Ni]−1·h−1). The use of Et3Al2Cl3results in the higher share of alkylated products (up to 60%). Moreover, catalytic systems activated withEt3Al2Cl3 produced small amounts of odd carbon number olefins (up to 0.8%). The Friedel-Craftsalkylation was used as a trap for previously undetected short-chain odd carbon number olefins (C3 andC5).