Cross-Metathesis and Hydrogenation in Polynorbornene–Poly(5-hydroxyoctenamer) Mixture in the Presence of Grubbs’ Catalysts

An exchange reaction of cross-metathesis between polynorbornene and poly(5-hydroxyoctenamer) in a chloroform–methanol mixture (10: 1 vol/vol) in the presence of Ru–carbene Grubbs’ complexes Gr-1 and Gr-2 has been studied. Gr-2 catalyst has a much higher activity and allows one to obtain multiblock c...

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Bibliographic Details
Published in:Polymer science. Series B 2018-11, Vol.60 (6), p.735-745
Main Authors: Denisova, Yu. I., Roenko, A. V., Gringolts, M. L., Krentsel, L. B., Peregudov, A. S., Shandryuk, G. A., Finkelshtein, E. Sh, Kudryavtsev, Y. V.
Format: Article
Language:English
Subjects:
Catalysis
Catalysts
Chemical synthesis
Chemical Transformations
Chemistry
Chemistry and Materials Science
Chloroform
Copolymers
Decomposition reactions
Hydrogenation
Metathesis
NMR spectroscopy
Polymer Sciences
Polynorbornene
Ruthenium
Spectrum analysis
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Summary:An exchange reaction of cross-metathesis between polynorbornene and poly(5-hydroxyoctenamer) in a chloroform–methanol mixture (10: 1 vol/vol) in the presence of Ru–carbene Grubbs’ complexes Gr-1 and Gr-2 has been studied. Gr-2 catalyst has a much higher activity and allows one to obtain multiblock copolymers, which cannot be synthesized directly from norbornene and 5-hydroxy-1-cyclooctene. The average length of the copolymer blocks varies in a wide range depending on the reaction conditions. The individual stages of the process have been studied with the use of in situ monitoring of transformations of Ru–carbene complexes by 1 Н NMR spectroscopy and ex situ analysis of heterodyad evolution in copolymers via 13 C NMR spectroscopy. As has been shown, poly(5-hydroxyoctenamer) forms Ru–carbene complexes with the catalyst more easily than polynorbornene; in this case, the incorporation of a substituent in the monomer unit of octenamer retards the polymer cross-metathesis. It has been found that, in systems containing Gr-2 and hydroxyoctenamer blocks, the formed ruthenium hydride complexes initiated hydrogenation process. The hydrogenation results in the appearance of crystallinity in the initially amorphous polymers, which opens up the possibilities for the targeted control of the multiblock copolymers properties.
ISSN:1560-0904
1555-6123
DOI:10.1134/S1560090418060052