Binuclear Cobalt(II) Complexes Formed by Bridging Arylphosphinic Acids in Tandem Catalytic Process of Ethylene Dimerization and Friedel–Crafts Alkylation of Toluene

A novel catalytic system based on 2,2'-bipyridine binuclear cobalt(II) complexes containing bridging phosphinic acid ligands (Ph2P(O)OH and MesP(H)(O)OH) is presented for tandem oligomerization of ethylene and subsequent Friedel–Crafts alkylation of toluene. It was found that incorporation of sterically less hindered {μ-O2P(H)Mes}– ligand significantly enhances the catalytic activity up to 1007 kg $${\text{mol}}_{{{\text{Co}}}}^{{ - 1}}\,\,{{{\text{h}}}^{{ - 1}}}$$ , doubling the value compared to the analogous complex with {μ-O2PPh2}– ligand. The reaction products were characterized by GC–MS analysis and include butenes, mono- and dibutyltoluenes along with minor amounts of ethyltoluenes, consistent with the mechanism involving ethylene oligomerization followed by toluene alkylation.