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Homogeneous olefin polymerization catalysts are activated in situ with a co-catalyst ([PhN(Me) 2 -H] + [B(C 6 F 5 ) 4 ] - or [Ph 3 C] + [B(C 6 F 5 ) 4 ] - ) in bulk polymerization media. These co-catalysts are insoluble in hydrocarbon solvents, requiring excess co-catalyst (&gt;3 eq.). Feeding the activated species as a solution in an aliphatic hydrocarbon solvent may be advantageous over the in situ activation method. In this study, highly pure and soluble ammonium tetrakis(pentafluorophenyl)borates ([Me(C 18 H 37 ) 2 N-H] + [B(C 6 F 5 ) 4 ] - and [(C 18 H 37 ) 2 NH 2 ] + [B(C 6 F 5 ) 4 ] - ) containing neither water nor Cl - salt impurities were prepared easily via the acid-base reaction of [PhN(Me) 2 -H] + [B(C 6 F 5 ) 4 ] - and the corresponding amine. Using the prepared ammonium salts, the activation reactions of commercial-process-relevant metallocene ( rac -[ethylenebis(tetrahydroindenyl)]Zr(Me) 2 ( 1 -ZrMe 2 ), [Ph 2 C(Cp)(3,6-  t  Bu 2 Flu)]Hf(Me) 2 ( 3 -HfMe 2 ), [Ph 2 C(Cp)(2,7-  t  Bu 2 Flu)]Hf(Me) 2 ( 4 -HfMe 2 )) and half-metallocene complexes ([(η 5 -Me 4 C 5 )Si(Me) 2 (κ-N  t  Bu)]Ti(Me) 2 ( 5 -TiMe 2 ), [(η 5 -Me 4 C 5 )(C 9 H 9 (κ-N))]Ti(Me) 2 ( 6 -TiMe 2 ), and [(η 5 -Me 3 C 7 H 1 S)(C 10 H 11 (κ-N))]Ti(Me) 2 ( 7 -TiMe 2 )) were monitored in C 6 D 12 with 1 H NMR spectroscopy. Stable [ L -M(Me)(NMe(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - species were cleanly generated from 1 -ZrMe 2 , 3 -HfMe 2 , and 4 -HfMe 2 , while the species types generated from 5 -TiMe 2 , 6 -TiMe 2 , and 7 -TiMe 2 were unstable for subsequent transformation to other species (presumably, [ L -Ti(CH 2 N(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - -type species). [ L -TiCl(N(H)(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - -type species were also prepared from 5 -TiCl(Me) and 6 -TiCl(Me), which were newly prepared in this study. The prepared [ L -M(Me)(NMe(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - -, [ L -Ti(CH 2 N(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - -, and [ L -TiCl(N(H)(C 18 H 37 ) 2 )] + [B(C 6 F 5 ) 4 ] - -type species, which are soluble and stable in aliphatic hydrocarbon solvents, were highly active in ethylene/1-octene copolymerization performed in aliphatic hydrocarbon solvents.

Preparation of High-Purity Ammonium Tetrakis(pentafluorophenyl)borate for the Activation of Olefin Polymerization Catalysts