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Competitive Chain Transfer by β-Hydrogen and β-Methyl Elimination for a Model Ziegler-Natta Olefin Polymerization System [Me_2Si(η^5-C_5Me_4)_2]Sc{CH_2CH(CH_3)_2}(PMe_3)

Hajela, Sharad and Bercaw, John E. (1994) Competitive Chain Transfer by β-Hydrogen and β-Methyl Elimination for a Model Ziegler-Natta Olefin Polymerization System [Me_2Si(η^5-C_5Me_4)_2]Sc{CH_2CH(CH_3)_2}(PMe_3). Organometallics, 13 (4). pp. 1147-1154. ISSN 0276-7333. https://resolver.caltech.edu/CaltechAUTHORS:20180521-131822953

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Abstract

The reaction of OpSc(H) (PMe_3) (Op = {(η^5-C_5Me_4)_2SiMe_2}) with isobutene produces OpSc(CH_3)(PMe_3) along with isobutene, 2-methylpentane, isobutene, 2-methyl-l-pentene, propane, and n-pentane. These products arise from a series of reactions involving olefin insertion, β-CH_3 and (faster) β-H elimination which proceed until only the 2-methyl-1-alkenes (C_4H_8, C_6H_(12), etc.) and the predominant organoscandium product OpSc(CH_3)(PMe_3) remain. A transient observed in the reaction sequence has been unambiguously characterized as OpSc(CH_2CH_2CH_3) (PMe_3). Slower u bond metathesis involving the methyl C-H bonds of PMe_3 and the Sc-C bonds of the scandium alkyls accounts for the observation of saturated alkanes (2-methylalkanes (C_4H_(10), C_6H_(14), etc.), normal alkanes (C_3H_8, C_5H_(12), etc.), and a minor organoscandium product OpScCH_2-PMe_2 in the product mixture. b-Ethyl migration is not observed for the closely related 2-ethylbutyl derivative, OpSC{CH_2CH(C_2H_5)CH_2CH_3}(PMe_3), obtained from reaction of 2-ethyl-1-butene with OpSc(H)(PMe_3).


Item Type:Article
Related URLs:
URLURL TypeDescription
https://dx.doi.org/10.1021/om00016a018DOIArticle
https://pubs.acs.org/doi/suppl/10.1021/om00016a018PublisherSupporting Information
Alternate Title:Competitive Chain Transfer by .beta.-Hydrogen and .beta.-Methyl Elimination for a Model Ziegler-Natta Olefin Polymerization System [Me2Si(.eta.5-C5Me4)2]Sc{CH2CH(CH3)2}(PMe3)
Additional Information:© 1994 American Chemical Society. Received July 27, 1993. We thank Dr. Les Field (University of Sydney) for his expert assistance in acquiring the NMR data. The work has been supported by USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER113431) and by Exxon Chemical Americas.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG03-85ER113431
Exxon Chemicals AmericaUNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Arnold and Mabel Beckman Laboratories of Chemical Synthesis8832
Issue or Number:4
Record Number:CaltechAUTHORS:20180521-131822953
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180521-131822953
Official Citation:Competitive Chain Transfer by .beta.-Hydrogen and .beta.-Methyl Elimination for a Model Ziegler-Natta Olefin Polymerization System [Me2Si(.eta.5-C5Me4)2]Sc{CH2CH(CH3)2}(PMe3) Sharad Hajela and John E. Bercaw Organometallics 1994 13 (4), 1147-1154 DOI: 10.1021/om00016a018
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86505
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:21 May 2018 20:41
Last Modified:03 Oct 2019 19:44

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