Vinyl-Type Addition Polymerization of Norbornene and Synthesis of Norbornene Macromonomers in the Presence of Ethylene Catalyzed by Cobalt(II)−Phosphine Complexes

Abstract

The polymerization of norbornene (NB) with catalysts obtained by combining cobalt-(II)-phosphine complexes (i.e., CoCl 2 (PR 3 ) 2 , CoCl 2 (PRPh 2 ) 2 , R = alkyl or cycloalkyl group, Ph = phenyl) with methylaluminoxane (MAO) is reported. These systems exhibited excellent activity when used in an halohydrocarbon solvent, yielding amorphous, soluble vinyl-type poly(norbornene)s (PNB)s. The NB copolymerization with ethylene (E) was also examined. Norbornene macromonomers (M n in the range 740-8740 g mol -1 ) with a terminal vinyl group, likely originating from insertion of one ethylene molecule followed by a β-hydrogen elimination reaction, were obtained in almost 100% yield. By varying the NB starting concentration as well as the time and the polymerization temperature, it was possible to tune the molecular weight of the macromonomers which exhibited different T g values upon the NB polymerization degree. The PNBs and the macromonomers were fully characterized by NMR analysis, and a reaction mechanism for the formation of the vinyl-end NB macromonomers in the copolymerization of NB with E is proposed.

Ni(II) and Pd(II) complexes bearing novel bis(β‐ketoamino) ligand and their catalytic activity toward copolymerization of norbornene and 5‐norbornene‐2‐yl acetate combined with B(C6F5)3

“…However, it shows poor processability and poor solubility. To modify the disadvantages and get functionalized PNB, a series of copolymers of NB with ethylene,22–28 propylene,29–31 higher 1‐alkene,32 polar monomer,33–35 and NB derivatives36–40 have been also studied.…”

“…The vinyl‐type PNB can be obtained through Ziegler‐Natta,22–25, 30–32 metallocene,12, 29 rare earth metal,26, 33, 41 and late transition metal catalysts 13–21, 27, 28, 34–40, 42–47. The late transition metal catalysts are simple to synthesize and show more stable to polar NB detectives.…”

Nickel(II) complexes bearing the bis(β‐ketoamino) ligand for the copolymerization of norbornene with a higher 1‐alkene

“…After the first NB insertion, the propagation proceeded, and the polymer chains grew. Therefore, because the planar conformation, normally required for b-H elimination, of a Ni-PNB bond intermediate in the exo position and of the b-H-carbon bond in the endo position is prohibited by Bredt's rule, 25 the b-H elimination could not happen in the homopolymerization procedure of NB. In the process of 1-alkene homopolymerization after the coordination and insertion, the 1-alkene connected with the Ni(II) active center that formed, and then, the steric hindrance of 1-alkene side chains may have inhibited the continuous chain propagation.…”

Phosphine (oxide)‐(thio) phenolate palladium complexes: Synthesis, characterization and (co)polymerization of norbornene

“…For homogeneous non‐metallocene catalysis systems, the development of new ligands has played an important role because of their remarkable influence on catalytic properties and the microstructure of obtained polymers. Various different ligands, such as bidentate ligands and tridentate ligands, including [N,N], [N,O], [6, 2c] [P,P], [N,P], [N,S], [O,O] and [N,N,X] (X = P, S), [C,N,X] (X = P, S), have been designed and extensively explored. However, most of pre‐catalysts bearing the aforementioned bidentate or tridentate ligands require a large amount of aluminum compounds (MAO, MMAO), the residue of which turns out to be harmful to the resultant polymer materials.…”