Nutation NMR Studies of Polyacetylene

Abstract

Using nutation NMR spectroscopy we have been able to determine directly the carbon-carbon bond lengths in polyacetylene. For trans-polyacetylene we find double and single bond lengths of 1.36 and 1.44 Å respectively ; the double bond in cis-polyacetylene is found to be 1.38 Å. Interestingly, at 77°K we do not observe a rapid interchange of the single and double bonds in trans-polyacetylene in the manner predicted for chains containing a soliton defect, suggesting that the majority of the carbons in the trans isomer are on conjugated segments which do not contain such mobile species

X-Ray Investigation on Highly Oriented Polyacetylene

“…FIGURE 5 Observed and calculated intensities of (hkl) and (hk2) reflections for all-trans and all-cis-PA. I' refers to calculated intensities in the presence of lattice defects.…”