Patent ID: 7820580

Claim:
A polymerization catalyst system comprising: (a) a nickel N-heterocyclic carbene complex; (b) an organoaluminum compound; (c) a fluorine-containing compound; and (d) optionally, an alcohol, where said fluorine-containing compound is selected from one or more of the following: (i) hydrogen fluoride, (ii) boron trifluoride, (iii) silicon tetrafluoride, (iv) aluminum trifluoride, (v) indium trifluoride, (vi) zinc difluoride, (vii) dimethylaluminum fluoride, (viii) diethyl aluminum fluoride, (ix) methylaluminum difluoride, (x) complexes of hydrogen fluoride with monohydric alcohols, phenols, water, mineral acids containing oxygen, water, aldehydes, esters, ethers, ketones or nitriles, or (xi) complexes of boron trifluoride with monohydric alcohols, phenols, water, mineral acids containing oxygen, water, aldehydes, esters, ethers, ketones or nitriles.