Poly(ethylene)-co-Poly(norborn-2-ene) Prepared by Group IV Bisamido and Half-Sandwich Amido Complexes with Pendant Aminoborane Groups: Vinyl Insertion vs Ring-Opening Metathesis Polymerization

A series of ZrIV and TiIV complexes containing the 6‐(2‐(diethylboryl)phenyl)pyridyl‐2‐yl motif are used in the methylalumoxane‐triggered copolymerization of ethylene (E) with norborn‐2‐ene (NBE). 13C NMR analyses reveal that vinyl insertion polymerization (VIP)‐derived poly(E)‐co‐poly(NBE) is obtained with pre‐catalysts 1–4 and 6, while pre‐catalyst 5 allows for the synthesis of a copolymer that contains both VIP‐ and ring‐opening metathesis polymerization (ROMP)‐derived structures. All the VIP‐derived poly(E)‐co‐poly(NBE) sequences show predominantly isolated NBE/alternating‐syndiotactic E‐NBE, as well as alternating‐isotactic E‐NBE sequences. The microstructure of the copolymers is correlated with the propensity of the pre‐catalysts to allow tandem ROMP‐VIP. Different group IV bisamido and half‐sandwich amido complexes are used in the copolymerization of ethylene (E) with norborn‐2‐ene (NBE). Depending on the pre‐catalyst, vinyl‐insertion polymerization (VIP), as well as VIP‐ and ring‐opening metathesis polymerization (ROMP)‐derived copolymers with predominantly isolated NBE/alternating‐syndiotactic E‐NBE and alternating‐isotactic E‐NBE sequences, respectively, are obtained.