Carbonyl-olefin Exchange Reaction Research Articles

Speculations on a possible mechanism of a tungsten catalyzed 1,2,3,3-tetraphenylprop-2-en-1-one polymerization

A mechanism is suggested for the reaction of 1,2,3,3-tetra-phenylprop-2-en-1-one (1) under the influence of some tungsten compounds containing WO or WC bonds. The processes involved in the polymerization of 1 are described as redistribution of atoms (C, O and W), involving four-membered metallacyclic transition states. The latter can be visualized by the schemes of olefin metathesis, carbonyl-olefin exchange reaction, reductive coupling of carbonyl compounds etc. These conclusions are confirmed by the fact that the processes under investigation can be catalyzed not only by tungsten oxocompounds but also by the stable Casey carbene.

Synthesis and properties of methylene bridged polyenes

Two new polymers with methylene bridged rans-cisoid polyene chains are prepared by the carbonyl-olefin exchange reaction. Since the single bonds of the chain are included in the rings, any free rotation along them is prevented and therefore the conjugation length cannot be changed. Due to the bulky rings a cis-trans isomerization is impeded and any defect state formed has to be localized. Upon doping with iodine, radical cations (polarons) are formed. This is proved by the I 3 − formation as counter ions and by ESR measurements. No changes in the IR spectra of the polymers after doping are observed. A comparison between two samples of the first polymer with different molecular weights doped to the same level shows a similar increase of conductivity (seven orders of magnitude). This indicates that conductivity is independent of conjugation length, especially when the polarons are localized as in this type of chain. The second polymer differs from the first one by its chain which is almost totally screened by substituents. This explains the small increase of conductivity upon doping (two orders of magnitude) and shows the role of the intermolecular interactions. Since the polarons in both doped polymers are localized, the charge transport is predominantly an intersite hopping process, which is supported by measurements of the temperature dependence of resistivity.

Carbonyl‐olefin exchange reaction. A new route to conjugated polymers, 5. Effect of different catalytic systems

The influence of experimental conditions and the nature of the catalytic system on the yield of products insoluble in methanol from the carbonyl-olefin exchange reaction (COER) was investigated. It was established that the COER of some α, β-unsaturated carbonyl compounds can be catalyzed by transition metal halides (WCl6, MoCl5), by oxo compounds (WOCl4), and by binary systems (WCl6 + AlCl3, MoCl5 + AlCl3). Under the influence of these catalysts, some α,β-unsaturated ketones can be transformed into conjugated polymers via different pathways. That is why the yield of the polymer product can be higher than calculated on the basis of the simple COER.

Carbonyl‐olefin exchange reaction. A new route to conjugated polymers, 6. Low‐molecular‐weight products

The processes which take place with the α,β-unsaturated compound 1,2,3,3-tetraphenyl-2-propen-1-one (1) under the influence of WCl6 were investigated. Special attention was paid to the low-molecular-weight products. It was established that beside polydiphenylacetylene and benzophenone also benzil, tetraphenylethylene and molecular oxygen are present in the product mixture. Their formation is explained as a result of a redistribution of the atoms connected with double bonds according to olefin metathesis (OM), carbonyl-olefin exchange reaction (COER) and reductive coupling (RC) of carbonyl compounds, accompanied by molecular oxygen evolution. The yields of products insoluble in methanol are sometimes higher than a simple stoichiometry would allow. This can be attributed to the participation of both the inner double bonds of the polymer and the low-molecular-weight products.

A carbonyl‐olefin exchange reaction. New route to conjugated polymers, 4. Chain growth. Side reactions

AbstractIn order to prove that the carbonyl‐olefin exchange reaction (COER) is a step reaction, a shorttime experiment was carried out, from which only linear oligomers were obtained. The dimer was identified by comparison with an authentic sample. The polymer can also be obtained starting from the dimer. The polymer retains its reactivity. Treated with WCl6 alone or in the presence of the corresponding monomer it yields products of increased molecular weight. The reaction takes place even in the presence of its low‐molecular‐weight by‐product benzophenone. Treatment of the polymer with benzophenone and WCl6 leads to a molecular weight increase. These results prove that the COER proceeds as a non‐equilibrium polycondensation.

A carbonyl‐olefin exchange reaction. New route to conjugated polymers, 2. A new synthesis of polydiphenylacetylene

Die Makromolekulare Chemie, Rapid CommunicationsVolume 6, Issue 10 p. 659-663 Article A carbonyl-olefin exchange reaction. New route to conjugated polymers, 2†. A new synthesis of polydiphenylacetylene‡ Ivan Schopov, Corresponding Author Ivan Schopov Central Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaCentral Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaSearch for more papers by this authorLyudmila Mladenova, Lyudmila Mladenova Central Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaSearch for more papers by this author Ivan Schopov, Corresponding Author Ivan Schopov Central Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaCentral Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaSearch for more papers by this authorLyudmila Mladenova, Lyudmila Mladenova Central Laboratory for Polymers, Bulgarian Academy of Sciences, 1040 Sofia, BulgariaSearch for more papers by this author First published: October 1985 https://doi.org/10.1002/marc.1985.030061005Citations: 14 † Part 1: cf.1 ‡ Dedicated to Prof. Dr. I. M. Panayotov on the occasion of his 60th birthday AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume6, Issue10October 1985Pages 659-663 RelatedInformation

A carbonyl‐olefin exchange reaction — new route to polyconjugated polymers, 1. A new synthesis of polyphenylacetylene

Die Makromolekulare Chemie, Rapid CommunicationsVolume 4, Issue 10 p. 659-662 Article A carbonyl-olefin exchange reaction — new route to polyconjugated polymers, 1. A new synthesis of polyphenylacetylene Ivan Schopov, Corresponding Author Ivan Schopov Central Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaCentral Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaSearch for more papers by this authorChristo Jossifov, Christo Jossifov Central Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaSearch for more papers by this author Ivan Schopov, Corresponding Author Ivan Schopov Central Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaCentral Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaSearch for more papers by this authorChristo Jossifov, Christo Jossifov Central Laboratory for Polymers, Bulgarian Academy of Sciences, Sofia 1040, BulgariaSearch for more papers by this author First published: October 1983 https://doi.org/10.1002/marc.1983.030041005Citations: 48AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume4, Issue10October 1983Pages 659-662 RelatedInformation