Catalyst activators comprising expanded anions

A catalyst composition comprising an activator corresponding to the formula:

• (A*+a)b(Z*J*j)−cd,
• wherein:
• A* is a cation of charge +a, selected from the group consisting of sulfonium-, phosphonium-, oxonium-, carbonium-, silylium-, ferrocenium-, Ag+, Pb+2 and trihydrocarbyl ammonium-cations,
• Z* is an anion group of from 1 to 50 atoms, not counting hydrogen atoms, further containing two or more Lewis base sites and selected from the group consisting of amide and substituted amide, amidinide and substituted amidinide, dicyanamide, imidazolide, substituted imidazolide, imidazolinide, substituted imidazolinide, tricycanomethide, tetracycanoborate, puride, 1,2,3-triazolide, substituted 1,2,3-triazolide, 1,2,4-triazolide, substituted 1,2,4-triazolide, pyrimidinide, substituted pyrimidinide, tetramidazoylborate and substituted tetraimidazoylborate anions, wherein each substituent, if present is a C1-20 hydrocarbyl, halohydrocarbyl or halocarbyl group, or two such substituents together form a saturated or unsaturated ring system;
• J* independently each occurrence is a Lewis acid compound having from 3 to 100 atoms not counting hydrogen coordinated to at least one Lewis base site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality,
• j is a number from 2 to 12 and
• a, b, c, and d are integers from 1 to 3, with the proviso that a×b is equal to c×d.