| Abstract: | Residual 740 cm?1 absorption, a signature of the cis isomer, is always observed to the extent of ± 5% in ‘trans’-polyacetylene prepared thermally from the Shirawaka cis isomer, regardless of the temperature or duration of treatment. The view that a significant fraction of the ‘remnant cis bonds’ is in the form of or can be converted to cisoid single bonds is supported by the results of a Diels-Alder trapping experiment with maleic anhydride. The presence of the remnant cis linkages leads to simple rationalisation of free radical (soliton) generation and diffusion, conjugation lengths determined by Raman spectroscopy, x-ray structural evolution and electrical conductivity. |
