Synthesis and molecular structures of neutral nickel complexes. Catalytic activity of (Benzamidinato)(acetylacetonato)nickel for the addition polymerization of norbornene, the oligomerization of ethylene, and the dimerization of propylene

Elza Nelkenbaum, Moshe Kapon, Moris S. Eisen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Scopus citations

Abstract

The new neutral nickel complexes PhC(NSiMe3)2Ni(acac) (3), PhC(NSiMe3)2Ni(acac)-(TMEDA) (4), [PhC(NSiMe 3)2]2Ni2 (5), [PhC(NSiMe 3)2]2Ni·Li2Br 2(TMEDA)2 (6), (TMEDA)2Ni (7), p-MePhC(NSiMe3)2Ni(acac) (8), p-MePhC(NSiMe 3)2Ni(acac)(TMEDA) (9), [p-MePhC-(NSiMe3) 2]2Ni (10), NiMe2Py2 (11) and [p-MePhC(NSiMe3)]2Ni(Py) (14) have been synthesized and characterized. The solid-state molecular structures of all complexes have been confirmed by low-temperature X-ray diffraction analysis. The methyl complex p-MePhC(NSiMe3)2Ni(Me)(Py) (13) is not stable and rapidly decomposes, forming the complex [p-MePhC(NSiMe3)]2-Ni(Py) (14). Complex 3 activated with MAO has been shown to be an efficient catalytic system for the norbornene vinyl-type polymerization. The activity of the catalyst and the molecular weights of the resulting polynorbornenes were found to be dependent on the reaction time, the MAO/precatalyst ratio, and the reaction temperature. In addition, this catalytic system has been found to dimerize propylene to a mixture of hexenes with a high turnover frequency of η = 9040 h-1 and oligomerize ethylene to either a mixture of C4-C6 or/and C4-C14 products, depending on the temperature and the solvent, extremely rapidly (η = 83 500 h-1).

Original languageEnglish
Pages (from-to)2645-2659
Number of pages15
JournalOrganometallics
Volume24
Issue number11
DOIs
StatePublished - 23 May 2005
Externally publishedYes

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