Determination of the tacticities of ring-opened metathesis polymers of symmetrical 5,6-disubstituted derivatives of norbornene and norbornadiene from the 13C NMR spectra of their hydrogenated derivatives

Autor:	Valia Amir-Ebrahimi, John J. Rooney, D.A.K Corry, James G. Hamilton
Rok vydání:	1998
Předmět:	Chemistry Process Chemistry and Technology Norbornadiene Carbon-13 NMR Metathesis Ring-opening polymerization Catalysis chemistry.chemical_compound Phenylacetylene Tacticity Polymer chemistry Organic chemistry Physical and Theoretical Chemistry Diimine Norbornene
Zdroj:	Journal of Molecular Catalysis A: Chemical. 133:115-122
ISSN:	1381-1169
DOI:	10.1016/s1381-1169(98)00101-0
Popis:	Ring-opened metathesis polymers were made from 5,6-di-exo-(carbomethoxy)-norbornene and 5,6-di-(carbomethoxy)-norbornadiene using a variety of catalysts and their 13 C NMR spectra analyzed in detail. These polymers were then fully hydrogenated using diimine and found by 13 C NMR analysis to give with complete selectivity the same saturated derivative. This permitted the tacticities to be assigned in detail and the consistency of the analysis further checked with respect to the m (meso) and r (racemic) line orders identified for all the precursor polymers. While OsCl3/phenylacetylene as catalyst gave high cis syndiotactic polymers OsCl3 by itself formed high trans atactic material; RuCl3 afforded the corresponding trans polymer with a substantial isotactic bias. By way of contrast MoCl5/Me4Sn in dioxan is an excellent catalyst for the synthesis of all cis isotactic poly-5, 6-di-(carbomethoxy)-norbornadiene.
Databáze:	OpenAIRE
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