A triphenylsiloxy complex of chromium(II) as a switchable catalyst for ethylene polymerization and nonselective oligomerization

Pengyuan Qiu, Ruihua Cheng, Boping Liu*, Boris Tumanskii, Rami J. Batrice, Mark Botoshansky, Moris S. Eisen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

A novel dinuclear oxygen-bridged chromium(II) complex of [(Ph 3SiO)Cr•(THF)]2(μ-OSiPh3)2 (1) was successfully synthesized and structurally characterized. The crystal structure of complex 1 shows that the chromium centers adopt a tetrahedrally distorted square-planar coordination geometry. Complex 1 was tested for ethylene polymerization upon activation with and without aluminum alkyl cocatalysts. No ethylene polymerization activity was observed in the absence of aluminum alkyl cocatalysts; however, in the presence of methylaluminoxane (MAO), complex 1 demonstrates an unexpected transformation from ethylene polymerization to ethylene oligomerization, with the molar ratio of Al to Cr increasing from 50 to 1000. The activation of complex 1 with MAO was investigated by ESR and 29Si NMR spectroscopy. It was found that the Ph3SiO- groups could be transferred from the chromium centers of complex 1 to the aluminum of MAO.

Original languageEnglish
Pages (from-to)2144-2148
Number of pages5
JournalOrganometallics
Volume30
Issue number8
DOIs
StatePublished - 25 Apr 2011
Externally publishedYes

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