Polymerization of norbornene in the presence of ethene over tetrakis(triphenylphosphine)nickel/boron trifluoride etherate system

Myagmarsuren, G.; Jeong, O-Yong; Ihm, Son‐Ki

doi:10.1016/j.apcata.2004.07.040

Cited by 10 publications

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References 15 publications

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“…Analogously in the 13 C NMR spectrum (Figure ) two resonances at about 111.9 and 139.9 ppm, respectively, attributable to an olefinic end group CH 2 CH, likely arising from a β-hydride elimination chain transfer, were observed. Therefore, since the planar conformation, normally required for β-H elimination, of a Copolynorbornyl bond intermediate in the exo position and of the β-H-carbon bond in the endo position is prohibited by Bredt’s rule, , the vinyl end group CH 2 CH−NB can be formed only through an insertion of an E molecule into the NB last inserted unit. , Thus, ethylene acts as an effective transfer agent in the vinyl-type NB polymerization mediated by Co−phosphine catalysts and MAO, yielding low- M n vinyl-end NB oligomers, as observed by Goodall and Ihm with Ni-transition-metal catalysts. , …”

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confidence: 91%

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

et al. 2009

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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.

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