Olefin Insertion into a Pd-F Bond: Catalyst Reactivation Following β-F Elimination in Ethylene/Vinyl Fluoride Copolymerization

Abstract

The discrete (phosphinoarenesulfonate)Pd fluoride complex (PO^Bp,OMe )PdF(lutidine), where PO^Bp,OMe =(2-MeOC₆ H₄ )(2-{2,6-(MeO)₂ C₆ H₃ }C₆ H₄ )(2-SO₃ -5-MeC₆ H₃ )P, inserts vinyl fluoride (VF) to form (PO^Bp,OMe )PdCH₂ CHF₂ (lutidine) and inserts multiple ethylene (E) units to generate polyethylene that contains -CH₂ F chain ends. These results provide strong evidence that the -CHF₂ and -CH₂ F chain ends in E/VF copolymer generated by (phosphinoarenesulfonate)PdR catalysts form by β-F elimination of Pd(β-F-alkyl) species, VF or E insertion of the resulting (PO)PdF species, and subsequent chain growth. These results also imply that β-F elimination is not an important catalyst deactivation reaction in this system.

Keywords: copolymerization; fluorides; olefin insertion; phosphine-sulfonate complex; β-F elimination.