Olefin polymerization activators

A process for polymerizing olefins, the process comprising contacting ethylene and a (C3-C40)alpha-olefin comonomer in the presence of a catalyst system in a solution polymerization reactor in an alkane solvent, the catalyst system comprising a procatalyst and a metallic activator ionic complex, the metallic activator comprising an anion and a countercation, the anion having a structure according to formula (I):

• where:
• n is 0 or 1;
• each R is independently selected from the group consisting of radicals having formula (II) and radicals having formula (III):
• each Y is independently carbon or silicon;
• each R11, R12, R13, R21, R22, R23, R24, and R25 is independently chosen from (C1-C40)alkyl, halogen-substituted (C1-C40)alkyl, (C6-C40)aryl, halogen-substituted (C6-C40)aryl, —ORC,—SRC, —H, —F or Cl, wherein at least one of R11-13 and one of R21-25 is a halogen-substituted (C1-C40)alkyl, a halogen-substituted (C6-C40)aryl, or —F;
• and
• each X is a monodentate ligand independently chosen from halogen-substituted (C1-C20)alkyl or halogen-substituted (C6-C40)aryl;
• optionally, two X groups in formula (I) are covalently connected;
• each RC is independently halogen-substituted (C1-C30)hydrocarbyl;
• provided that
• when the countercation is Me2PhN(H)+, and the anion is Al(C6F5)4, the procatalyst is not Ph2C(Cp)(Flu)ZrCl2 or Et(1-Ind)2ZrCl2;
• and
• when the countercation is (Ph)3C+, and the anion is Al(C6F5)4, the procatalyst is not Et(1-Ind)2ZrCl2.