Nickel Indenyl Complexes as Catalysts for the Dimerization and Polymerization of Ethylene
| Autor: | Marc-André Dubois, Ruiping Wang, Jun Tian, Rainer Vollmerhaus, Scott Collins, Davit Zargarian, and Zengmin Li |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
chemistry.chemical_classification
Ethylene Molecular mass Chemistry Organic Chemistry Cationic polymerization chemistry.chemical_element Polymer Catalysis Inorganic Chemistry chemistry.chemical_compound Nickel Polymerization Electrophile Polymer chemistry Organic chemistry Physical and Theoretical Chemistry |
| Zdroj: | Organometallics. 20:663-666 |
| ISSN: | 1520-6041 0276-7333 |
| DOI: | 10.1021/om000872+ |
| Popis: | The nickel indenyl compounds Ind(PR3)Ni-X (Ind = indenyl and its substituted derivatives; R = Ph, Cy, Me; X = Cl, Me, CCPh) can dimerize and/or polymerize ethylene in the presence of suitable activators. For example, poly(methylaluminoxanes) (PMAO) combine with these Ni precursors to produce catalytically active species for both the dimerization and polymerization of ethylene. The polymers obtained from these reactions are mostly linear polyethylenes which contain a small number of ethyl branches and exhibit molecular weights in the range of Mw = 105 (Mw/Mn ca. 2). On the other hand, using activators such as AgBF4, AlCl3, and B(C6F5)3 leads to the exclusive formation of butenes. It is proposed that the latter activators convert the Ni precursors to the highly electrophilic cations [IndNi(PR3)]+, which efficiently catalyze the dimerization of ethylene to butenes; in contrast, Ni/PMAO combinations give both the aforementioned cationic species as well as neutral species bearing a Ni(μ-Me)Al core, which is th... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|