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Microstructural studies of poly(7-oxabicyclo[2.2.1]hept-2-ene) derivatives prepared from selected ruthenium catalysts

Benedicto, Alto D. and Novak, Bruce M. and Grubbs, Robert H. (1992) Microstructural studies of poly(7-oxabicyclo[2.2.1]hept-2-ene) derivatives prepared from selected ruthenium catalysts. Macromolecules, 25 (22). pp. 5893-5900. ISSN 0024-9297. https://resolver.caltech.edu/CaltechAUTHORS:20180720-125619617

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Abstract

The microstructures of polymers prepared from ring-opening metathesis polymerization (ROMP) of 7-oxanorborene (7-oxabicyclo[2.2.11 hept-2-ene) (3), endo-5-(methoxymethyl)-7-oxanorbornene (2), and exo,exo-5,6-bis(methoxymethyl)-7-oxanorbornene (1) with four metathesis catalysts were studied by ^1H and ^(13)C NMR spectroscopy. Tacticities were determined by hydrogenation of the polymers (which removed double-bond isomerism) and also by ROMP of (S)-endo-5-(methoxymethyl)-7-oxanorbornene (2S)(which related head-tail isomerism with tacticity). Polymers prepared from W(CH-t-Bu)(NAr)(OCMe(CF_3)_2)_2 (Ar = 2,6-diisopropylphenyl) (6) have all cis double bonds and are highly syndiotactic, while those from RuCl_3•3H_2O (8) and [RCl(µ-Cl)(η^3:η^3-C_(10)H_(16)]_2 (C_(10)H_(16)) = 2,7-dimethyloctadienediyl) (9) have a high trans double-bond content and are highly isotactic. Polymers prepared from [Ru(H_2O_6](tosylate)_2 (7) exhibit roughly equal amounts of cis and trans double bonds that are randomly distributed in the polymer chain and are atactic. The apparent correlation between double-bond isomerism and tacticity for a classical hexacoordinated metal center is consistent with the model proposed by Ivin and co-workers.


Item Type:Article
Related URLs:
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https://dx.doi.org/10.1021/ma00048a006DOIArticle
ORCID:
AuthorORCID
Grubbs, Robert H.0000-0002-0057-7817
Additional Information:© 1992 American Chemical Society. Received April 22, 1992; Revised Manuscript Received July 8, 1992. Financial support from the National Science Foundation is gratefully acknowledged. A.D.B. thanks Dr. Greg Fu and Zhe Wu for their suggestions in preparing this manuscript.
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Arnold and Mabel Beckman Laboratories of Chemical Synthesis8727
Issue or Number:22
Record Number:CaltechAUTHORS:20180720-125619617
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180720-125619617
Official Citation:Microstructural studies of poly(7-oxabicyclo[2.2.1]hept-2-ene) derivatives prepared from selected ruthenium catalysts Alto D. Benedicto, Bruce M. Novak, and Robert H. Grubbs Macromolecules 1992 25 (22), 5893-5900 DOI: 10.1021/ma00048a006
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88066
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:23 Jul 2018 21:00
Last Modified:03 Oct 2019 20:02

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