Boron-based Co-catalyst for Polymerization Using Metallocenes

Triphenylmethylium tetrakis(pentafluorophenyl)borate (1) is a co-catalyst for olefin polymerization using metallocene catalysts. In 1980, Kaminsky et al. used methylaluminoxane (MAO) as a co-catalyst in order to highly activate metallocene complexes, however it was necessary to use an excessive amount of MAO, which is prepared from expensive trimethylaluminum. An alternate co-catalyst to MAO, 1 shows catalyst performance by forming an ion pair with the metallocene complex. It has been reported that 1 is also used as a co-catalyst in polymerization by half-metallocene catalysts and post-metallocene catalysts.