Surface organometallic chemistry: a route to well-defined boron heterogeneous co-catalyst for olefin polymerisation

The reaction of tris(pentafluorophenyl)borane, B(C6F5)3 with surface silanol (=Si-OH) of silica occurs only in the presence of a Bronsted base (diethylaniline, Et2NPh), which does not form a complex with B(C6F5)3, and affords selectively a well-defined ionic entity [=SiO-B(C6F5)3]-[HNEt2Ph]+. With a strong nucleophile base such as pyridine (C5H5N), the complex (C6F5)3B.NC5H5 is formed and is only physisorbed onto silica surface. Without a base, B(C6F5)3 does not react with (=Si-OH), and is only physisorbed. On the contrary, with any molecular compound ROH, B(C6F5)3 forms a stable complex (C6F5)3BO(H)R.