Derivatives of polyacetylene

Substituted polyacetylenes have not been studied for their conduction properties, but rather for different high-performance features. Substituents appear to reduce conjugation by introducing twists in the main chain. Structural data on polyphenylacetylene have been reported by Simionescu and Percec [155] these can be found in the 1986 Handbook [156]. A polymer stnicturally related to polyacetylene, poly( 1,6-hepta-diyne), is briefly dealt with in Section 7.2 of this chapter. 

A recent study related to the current topic concerns the chlorination of polyacetylene, and addresses a new aspect of chemical doping. Akagi et al. [157] show that iodine doping of stretched polyacetylene films followed by chlorination produces stereoregularly chlorinated 

FeCl4 FeBr4 GaC - lnCl4- TICI4- CIO4- Note 

Combined x-ray and neutron diOraclion data Electron diflraclion data 

Value ntarked with is (200) spacing for stage-2 intercalate Highly oriented Akagi polyacelylenc, l/lg 6 Highly onented Tsukamoto polyacetylcnc. 

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Shirakawa H, Louis EJ, MacDiarmid AG, Chiang CK, Heeger AJ (1977) Synthesis of electrically conducting organic polymers halogen derivatives of polyacetylene, (CH)X. J Chem Soc Chem Commun 578-580... 

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. 

This chapter will focus on some recent developments in the synthesis of polyacetylene itself, (CH) , and of substituted derivatives, (CR) f(CH) [24, 25]. While the great variety of other conductive polymers, including poly(phenylene vinylenes), polythiophenes and polypyrroles, may be thought of as annulated derivatives of polyacetylene [26-28], (Fig. 10-4), their syntheses and properties differ enough to put them outside the scope of this chapter. The reader is referred to a number of reviews covering both these polymers and polyacetylene [15,17, 29]. 

A derivative of polyacetylene that is more stable in air and soluble in organic solvents when doped with iodine, is polytrimethyl-silylacetylene (PTMSA). Though the derivative has a conductivity only one ten-millionth that of doped polyacetylene, it can be used as precursor to a wide range of other conductive derivatives. One such derivative is polyfluoroacetylene (polyacetylene in which all of he hydrogen atoms are replaced by fluorine), which according to calculations, would be electrically conductive without the need of dopants. 

H. Shirakawa, E.J. Louis, A.G. MacDiarmid, C.K. Chiang, and A.J. Heeger, Synthesis of electrically conducting organic polymers Halogen derivatives of polyacetylene, (CH)x, Chem. Commun., 578-580 (1977). 

Gorman, C.B., Ginsburg, E.J., Grubbs, R.H., 1993. Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes synthesis and the relationship between polymer structure and physical properties. I. Am. Chem. Soc. 115, 1397-1409. 

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