Poly acetylene soluble

Feast, W. J. et al J. Chem. Soc., Chem. Comm., 1985, 202-203 The second stage of an improved synthesis of poly(acetylene), which involves disproportionation of a soluble polymer by heating a thin film at 75°C to give 1,2-bis(trifluoromethyl)benzene and poly(acetylene), must not be done in bulk because the reaction then becomes explosive. The earlier synthesis by direct polymerisation of acetylene was considerably more dangerous... 

Initially alkynes were polymerised by trial and error with the use of Ziegler type recipes and the mechanism for these reactions may well be an insertion type mechanism. Undefined metathesis catalysts of ETM complexes were known to give poly-acetylene in their reaction with alkynes (acetylene) [45] and metallacycles were proposed as intermediates. Since the introduction of well-defined catalysts far better results have been obtained. The mechanism for this reaction is shown in Figure 16.24 [46], The conductive polymers obtained are soluble materials that can be treated and deposited as solutions on a surface. 

Poly (acetylenes) [16], There are several catalysts available for polymerization of substituted acetylenes. Whereas Ziegler-Natta catalysts are quite effective for polymerization of acetylene itself and simple alkylacetylenes, they are not active towards other substituted acetylenes, e.g. phenylacetylenes. Olefin-metathesis catalysts (Masuda, 1985 Masuda and Higashimura, 1984, 1986) and Rh(i) catalysts (Furlani et al., 1986 Tabata, 1987) are often employed. In our experience, however, many persistent radicals and typical nitrogen-containing functional groups serve as good poisons for these catalysts. Therefore, radical centres have to be introduced after construction of the polymer skeletons. Fortunately, the polymers obtained with these catalysts are often soluble in one or other organic solvent. For example, methyl p-ethynylbenzoate can be polymerized to a brick-coloured amorph- See the Appendix on p. 245 of suffixes to structural formula numbers. 

Partially substituted derivatives of polyacetylene are synthesized via the ring-opening metathesis polymerization (ROMP) of cyclooctatetraene (COT) and its derivatives. Certain poly-COT derivatives afford soluble, highly conjugated poly acetylenes. These materials exhibit large third-order optical nonlinearities and low scattering losses. 

Scheme 5.2. Synthesis of polyacetylene by the Durham route. The precursor polymer is soluble and can be processed prior to conversion to poly acetylene.

Miscellaneous Polymers - Soluble fluorescent extraction products from poly(acetylene) have been compared with those present in PVC. Photo-Fries rearran ments in the photodegradation of a Bis-Phenol-A poly(carbonate) are responsible for their stability. PTFE has been irradiated using high energy UV and found to give volatile fluorocarbons while photooxidation of poly(phenyl-ene) gives crosslinked and quinone methide products. A polyradical has been made based on poly(3,5-di-tert-butyl-4-[(2,4,6-tri-tert-butylphenyl)oxalato]phe-... 

Insolubility and infusibility of poly acetylene make it impossible to determine its molecular weight by the usual methods based on solutions. Several attempts have been made either to convert polyacetylene to soluble derivatives in order to measure their molecular weight... 

Nagai, K., Kanehashi, S., Tabei, S. and Nakagawa, T. 2005. Nitrogen permeability and carbon dioxide solubility in poly(l-trimethylsilyl-l-propyne)-based binary substituted poly acetylene blends. 251(1-2) 101-110. 

Silicon-containing compounds can be used as starting materials for the preparation of soluble poly acetylenes [78] with molecular weight lO in an inert atmosphere at temperatures from -10 up to 150°C in the presence of a catalyst on a base of W(3+) and W(4+) and cocatalysts such as Li- or Mg-organic compounds and others that reduce (W(6-t-) to W(3+) and W(4h-). A similar method allows the production of soluble copolymers of polymethylsilylacetylene with acetylene, acetylacetylene, and benzoylacetylene. 

Reibel, D., Nuffer, R., and Mathis, C., Doped and undoped soluble block copolymers poly(styrene) poly(acetylene), Synth. Met., 55, 791-796 (1993). 

An alternative to the threading, shpping and clipping routes dealt with so far, is to join two half-threads in the presence of a potential ring. This synthetic method was successfully apphed to the preparation of singly- and doubly-ringed poly-acetylenic threads (LlllO from Lilli Eq. 4.70). Diedrich s cyclophane (L1112) conferred water solubility on these rotaxanes [223]. 

The synthesis of polymers from substituted acetylene monomers is directed toward the preparation of substituted, conjugated chains which ameliorate the negative properties of poly(acetylene)s (e.g., sensitivity to air, insolubility, and infusibility) while maintaining the desired electrical properties of acetylene s conjugated backbone alkyl- and aryl substituted polymers result. They are soluble (e.g., in toluene and cyclohexane) and proccessible, but have low conductivities (<0.1 S/cm) compared with the unsubstituted poly(acetylene). 

Aldissi, M. (1984) Soluble conducting poly(acetylene) block copolymers. Journal of the Chemical Society. Chemical... 

A Ta vinylalkylidene complex 6, confirmed by a single crystal X-ray analysis, was revealed to polymerize 2-butyne in a manner of living polymerization.The initiation efficiency is quantitative, and the living end can be end-capped with aromatic aldehydes. As polymers from symmetric acetylenes are generally insoluble, soluble poly(2-butyne) is accessible if the degree of polymerization is suppressed below 200. The NMR analysis of living oligomers of 2-butyne clearly indicates that both cis- and 7ra r-structures exist in the main chain. 

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