Structure of cynacetylene polymers

Yuzhakova, O. A.; Isakov, I. V.; Герасимов, Г. Н.; Abkin, A.D.

doi:10.1016/0032-3950(84)90115-1

Cited by 6 publications

(9 citation statements)

References 2 publications

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“…Thus, it is hypothesized that these color differences are due to differences in polymer molecular weight. In earlier studies of cyanoacetylene polymerizations, a deep blue to purple polymer could be obtained using γ-ray initiation . Furthermore, in that study, the λ max of the electronic absorption also shifted depending upon the solvent used to extract/dissolve the poly(cyanoacetylene).…”

Section: Resultsmentioning

confidence: 80%

“…Reports of the appearance of the polymer have varied as well. γ-ray initiated radical polymerization also produced low yields of poly(cyanoacetylene). , Polymer produced this way was reported to be blue-purple in color, as compared to the black or brown polymers produced by the previously mentioned systems. Although the polymers produced by γ-rays did not exhibit any significant structural differences as determined by infrared or NMR spectroscopy, compared to poly(cyanoacetylene) synthesized via anionic, Ziegler−Natta, or metathesis catalysts, these differences in optical absorption indicate that poly(cyanoacetylene) prepared by most routes has a low effective conjugation length. , This low effective conjugation length could be due to low molecular weight or due to twisting of the polymer chain.…”

Section: Introductionmentioning

confidence: 92%

“…Cyanoacetylene has been polymerized using a variety of catalysts including bases/anions, γ-ray initiated radicals, and Ziegler−Natta catalysts. − The yield and molecular weights of polymer produced with these catalysts have been generally unreported or low. Reports of the appearance of the polymer have varied as well.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Poly(cyanoacetylene) Using Late-Transition-Metal Catalysts

et al. 1999

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Poly(cyanoacetylene) has been prepared by polymerization of cyanoacetylene using a variety of late-transition-metal (Pd- and Ni-based) catalysts. The effect of reaction conditions on molecular weight and polymer yield was explored. Significant catalyst residues remain in the polymer samples. However, spectra are consistent with the proposed poly(cyanoacetylene) structure. Notable differences in molecular weight, effective conjugation length, and ability to undergo thermal cyclization to a supposed aromatic ladder polymer were observed between these polymers and those prepared using conventional anionic or radical initiators.

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Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Preparation of Poly(cyanoacetylene) Using Late-Transition-Metal Catalysts

et al. 1999

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“…[20] Since repetition of these experiments in our hands in a 2-methylbutan/2-methylpentane glass at Ϫ196°C also did not provide monomeric isomerization products (formation of oligomers of unknown structure), we decided to subject the sterically more shielded [6]radialene derivative 2c to photolysis. Although initial experiments were also disappointing (formation of viscous oils of undetermined structure), we were pleased to find that irradiation with a 15 W low-pressure mercury lamp at a wavelength of 254 nm in hexane solution for short reaction times (minutes, see below and Exp.…”

Section: The Photochemical Isomerization Of Dodecamethyl[6]radialene mentioning

confidence: 99%

[6]Radialenes Revisited

et al. 2003

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[6]Radialene (2d) and its hexa-(2a) and dodecamethyl (2c) derivatives were subjected to several novel chemical reactions. Pyrolysis of 2a under flash vacuum conditions provided a mixture of 1,5-hydrogen shift products 9 and 10, and the benzocyclobutenes 5 and 6, produced by electrocyclization of an intermediate o-xylylene derivative 7. At the higher end of the investigated temperature range (200−400°C) the formation of cyclization products 11 was also observed. The hydrocarbon 2c isomerized to the benzocyclobutene 12 under these conditions. Photolysis at 254 nm converted 2c into a novel isomer that, according to X-ray structural analysis, has the unusual twist configuration 14. Compound 2c was photoisomerized through photoinduced hydrogen shift reactions to 15, and the stable p-xylylenes 16 and 17. Dichloroand dibromocarbene add to 2d with formation of the rotaradialene anti adducts 19a and 19b, respectively, the structures of which were also established by X-ray structural analysis. With dichlorocarbene, 2a provided the three dichlorocarbene adducts 20, 22, and 23, whereas methylenation with diiodomethane/trimethylaluminium afforded a complex product

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“…Experimental studies of final photoproducts are not as definitive. While all irradiations of HC3N report a brown or black polymer as the major product regardless of incident wavelength [Ferris and Guillemin, 1990;Yuzhakova et al, 1984;Carlini, 1984], other nonvolatile products, whose formation is wavelength dependent, have also been isolated and identified. For example, 1,3,5-tricyanobenzene (1,3,5-tcb) is formed using 185-or 206-nm irradiation, and 1,2,4-tricyanobenzene (1,2,4tcb) and tetracyanocyclooctatetraenes (TCCOTs) are formed using 254-nm light (Figure 1 and Table 1).…”

Section: Introductionmentioning

confidence: 99%

Mechanism of cyanoacetylene photochemistry at 185 and 254 nm

Clarke¹,

Ferris²

1996

J. Geophys. Res.

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The role of cyanoacetylene (HC3N) in the atmospheric photochemistry of Titan and its relevance to polymer formation are discussed. Investigation of the relative light absorption of HC3N, acetylene (C2H2), and diacetylene (C4H2) revealed that HC3N is an important absorber of UV light in the 205- to 225-nanometer wavelength region in Titan's polar regions. Laboratory studies established that photolysis of C2H2 initiates the polymerization of HC3N even though the HC3N is not absorbing the UV light. Quantum yield measurements establish that HC3N is 2-5 times as reactive as C2H2 for polymer formation. Photolysis of HC3N with 185-nanometer light in the presence of N2, H2, Ar, or CF4 results in a decrease in the yield of 1,3,5-tricyanobenzene (1,3,5-tcb), while photolysis in the presence of CH4, C2H6, or n-C4H10 results in an increase in 1,3,5-tcb. The rate of loss of HC3N is increased by all gases except H2, where it is unchanged. It was not possible to detect 1,3,5-tcb as a photoproduct when the partial pressure of HC3N was decreased to 1 torr. Photolysis of HC3N with 254-nanometer light in the presence of H2 or N2 results in the formation of 1,2,4-tcb, while photolysis in the presence of CH4, C2H6, or n-C4H10 results in the formation of increasing amounts of 1,3,5-tcb. Mechanisms for the formation of polymers are presented.

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Structure of cynacetylene polymers

Cited by 6 publications

References 2 publications

Preparation of Poly(cyanoacetylene) Using Late-Transition-Metal Catalysts

Preparation of Poly(cyanoacetylene) Using Late-Transition-Metal Catalysts

[6]Radialenes Revisited

Mechanism of cyanoacetylene photochemistry at 185 and 254 nm

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