The structure of polyconjugated macromolecules

Recent experimental results concerning the crystal structure and morphology of nascent cis-poly-acetylene and pristine trans-polyacetylene are discussed. The unit cell data of cis-PA and two different modifications of trans-PA are reported. The chlorination and the hydrogenation of PA both of which give soluble derivatives under certain experimental circumstances are critically discussed. PA prepared by the Shirakawa technique has a lamellar morphology with some evidence for chain folding and not a fibirillar texture as sometimes assumed. The synthesis and spectral properties of polyenylanions and -cations are reported as a new class of polyconjugated macromolecules. The so-called doping of PA to produce highly conducting phases is explained as a chemical reaction giving rise to intermolecular CT-interaction. Finally, some new experiments concerning the solution properties of polydiacetylenes and the question of effective conjugation length in polyunsaturated polymers are discussed.