Polymerization of Norbornene Using Cationic (p-allyl)Ni(II) Dialkylbiaryl Phosphine Complexes

Abstract

The polymerization of norbornene is of interest to study because there is a wide array of cheap commercially available monomers and the polymer product is value-added and has a number of commercial applications. Norbornene can be polymerized via a number of methods but the vinyl addition polymerization is of interest to this work. Here we report the polymerization of norbornene initiated via cationic (π-allyl)nickel complexes containing a phosphine ligand with different bulky substituents. The reaction conditions, temperature, solvent, and time were screened to improve the polymer yield. The resulting polymer was characterized using IR spectroscopy. Previously in the O’Connor lab, a side reaction was discovered during the preparation of the cationic nickel complexes when diethyl ether and dichloromethane were used as solvents. After evaluating the reaction conditions to prepare nickel complexes 1-7, the salt was only observed in reactions involving the preparation of complexes 1 and 7.