Ni(ii) complexes were successfully synthesized and characterized, and were highly active toward (co)polymerization of norbornene, and the 1-hexene content could be controlled.
Novel nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands, bis‐(salicylaldnaphthylmethyleneimino)Ni(II) (Ni{(3‐R1)(5‐R2)C6H2(O)CH[N (naphthyl‐CH2)]}2 Ni1: R1 = H, R2 = H; Ni2: R1 = H, R2 = CH3; Ni3: R1 = H, R2 = Br; Ni4: R1 = H, R2 = OCH3; Ni5: R1 = CH3, R2 = H; Ni6: R1 = Br, R2 = H), were synthesized. Ni2, Ni3, Ni5, and Ni6 are clearly characterized by single‐crystal X‐ray diffraction. Co‐polymerization of norbornene (NB) with 5‐norbornene‐2‐methylene butyl ether (BN) was carried out in toluene with the aforesaid complexes as catalyst precursors and B(C6F5)3 as the co‐catalyst. Catalyst activity, molecular weight, thermal stability, solubility, regularity, and optical transparency were investigated, and the mechanism of the electron groups changing catalyst performance is explained. All catalysts show high activity toward co‐polymerization (up to 3.53 × 105 gpolymer molNi−1 h−1). Ni3 shows the highest activity and Ni5 shows the highest insertion rate (up to 37.6%). The obtained poly(NB‐co‐BN)s are confirmed to be vinyl‐addition‐type co‐polymers, and they are noncrystalline. The co‐polymers exhibited excellent thermal stability and processability (Td ≥ 400 °C, Tg < 240 °C), optical transparency (up to 90%), and good solubility.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.